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FAQ

Ask an Expert

If you have a question about wild birds, send it to us using the form below. Each week, we'll select one to answer as our Question of the Week. We apologize that because of the high volume of questions we receive, we are unable to reply personally to them all. Please understand that we are not a veterinary organization, and we are unable to answer questions about pet birds.

You can also share lively discussions about wild birds on our Facebook page.

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Frequently Asked Questions

Tip: To search for text on this page, type Control-F (Command-F on a Mac) and type your text into the search box that appears (at the bottom left of the window in most Internet browsers).

1. Baby Birds

Q. How long do birds incubate their eggs, and how long do the chicks stay in the nest?

Q. I found a baby bird. What should I do?

Q. If I don't pick up a baby bird, will my cat or dog kill it?

Q. Can I raise a baby bird I found?

Q. If I handle a baby bird, will the parents abandon it?

Q. I found some abandoned eggs. Can I take them to a rehab center to raise them?

Q. Why do birds leave the nest before they can fly?

Q. Do young birds recognize their parents after they've grown up?

2. Sick and Injured Birds

Q. What do I do if I find a sick, injured, or dead bird?

Q. How can I tell if a sick bird has West Nile Virus?

Q. I've seen a sick House Finch with red, swollen, or weepy eyes. What's wrong with it?

Q. I have a bald bird at my feeder. Is it sick?

Q. What can cause an adult bird to die inside a birdhouse or nest box?

Q. I've seen a bird with an overgrown or otherwise deformed bill. What is wrong with it?

3. Bird Feeding

Q. Should I take my feeder down when the weather starts to warm up?

Q. My feeders are being overrun with starlings and blackbirds that eat all the food and keep smaller birds away. What can I do?

Q. What's the best recipe for hummingbird nectar?

Q. Should I use red food coloring in hummingbird food?

Q. Why do I see fewer hummingbirds in midsummer?

Q. Should I stop feeding birds in fall so they can start their migration?

Q. A hawk has started hunting the feeder birds in my yard. What can I do?

Q. What should I do if I find algae in my birdbath?

Q. I’m seeing fewer birds in my yard. Is something affecting their populations?

Q. I live in a high-rise apartment in the city. How can I attract birds?

Q. Do birds store food for the winter?

Q. What are owl pellets?

Q. How do I keep ants out of my hummingbird feeder?

Q. How do I keep the squirrels in my yard away from my feeders and bird seed?

4. Bird Identification

Q. What's the best book or field guide for bird identification?

Q. I saw a black-and-white bird at my feeder with a red triangle on the breast. What is it?

Q. Yesterday evening around dusk I watched hundreds and hundreds of birds flying over my house. What were they?

Q. There's a bird in my yard I've never seen before. How can I find out what it is?

Q. The goldfinches at my feeder are starting to look dull and patchy. What's happening to them?

Q. I saw a House Finch that was orange or yellow instead of red. What happened to it?

Q. What can cause birds to show weird color variations, such as being all or partly white, or unusually dark?

Q. Why are some species found out of their normal range more than others?

Q. What should I do to report a rare bird?

Q. What are some ways to enjoy birding on a budget?

Q. How can I adjust my binoculars so I see a good image without blacked-out areas?

Q. I've just upgraded my optics. What should I do with my old binoculars?

Q. I often see birds on telephone wires while I’m driving—how do I figure out what they are from such a short glimpse?

5. Migration

Q. Do hummingbirds migrate in flocks?

Q. How do hurricanes affect migrating birds?

Q. Is it unusual to see American Robins in the middle of winter?

Q. Do backyard birds return to the same spot year after year?

Q. How do birds prepare for long migrations?

Q. Can you really use weather radar to see migrating birds?

Q. Is it possible I've heard a whole flock of swans migrating overhead late at night?

Q. There's a hummingbird at my feeder in the dead of winter. Will he be okay?

Q. Where can I go to watch hawk migration?

Q. I thought geese migrated south in the winter and north in the summer. Why did I just see a flock of Canada Geese flying in the "wrong" direction?

Q. Why do migratory birds crash into buildings at night and how can people prevent it from happening?

Q. I’m getting a little tired of winter—What are some of the first spring birds to arrive, and when will they get here?

Q. How long do wintering Snowy Owls stay with us before they return to their breeding grounds?

6. Birds and People

Q. In your opinion, what bird species is the most beneficial to mankind throughout planet Earth?

Q. I’m getting married next month. Is it true that rice causes birds’ stomachs to explode?

Q. It sounds like there are birds stuck in my chimney. What should I do?

Q. Should I worry that my small, five-pound dog might get attacked by a hawk or owl?

Q. How do I keep herons from eating the fish in my pond?

Q. There's a huge starling roost near my house and they're driving us nuts! What can we do?

Q. Why do woodpeckers like to hammer on houses? How can I get woodpeckers to keep visiting my feeders but leave my house alone?

Q. A woodpecker is putting rows of holes in my tree. Will it hurt the tree?

Q. What can I do about a bird that sings all night long outside my window?

Q. I found a pigeon or dove that seems tame and has colored bands on its legs. What should I do?

Q. How can I share my bird photos with the Lab?

Q. How can I keep birds from hitting my windows?

7. Bird Sounds

Q. Why do some birds mimic the sounds of other species?

Q. Which birds are the best mimics?

Q. Do parent and baby birds recognize each other's songs or calls?

Q. Do bird songs have frequencies higher than humans can hear?

Q. What is the most beautiful bird song in North America?

Q. Why are Blue Jays far more noisy in fall than earlier in the summer?

Q. How does a tiny bird like a Winter Wren manage to sing so many sounds so quickly, and so loudly?

Q. I've been hearing beautiful bird songs every morning since spring, but suddenly I'm not hearing birds at all! What happened to them?

8. Science and Conservation

Q. Do all birds have gizzards?

Q. Why can't penguins fly?

Q. Do vultures find dead animals by smell or by tracking predators or scavengers on the ground?

Q. On a visit to Ithaca, New York, I saw a crow with large, red tags on each shoulder. Is this one of your projects?

Q. I believe that the same blue heron has been perching on my dock for 28 years. What is their life span?

Q. How much do birds eat each day?

Q. How can Bald Eagles survive in northern areas after all the lakes have frozen?

Q. Why don't birds get cold feet?

Q. Do birds have teeth?

Q. Why are loons chasing each other across my lake?

Q. Do hawks flock together?

Q. How are coffee and birds related?

Q. How can coffee help or harm birds?

Q. Is drinking shade-grown coffee good for birds?

Q. What's the difference between shade-grown, organic, fair-trade, and Bird-Friendly coffee?

Q. Why do female Belted Kingfishers have an extra rust-colored “belt” that the males don’t have?

Q. Why don’t birds collide when they are flying close together in tight flocks?

Q. How can an owl catch a mouse underneath a foot of snow in total darkness?

Q. Are Whip-poor-will populations declining? What can we do about it?

Q. What is the Migratory Bird Treaty Act?

9. Bird Breeding and Nests

Q. There's a bird nesting near my house. What should I do?

Q. I found a songbird nest with two different types of eggs in it. What is going on?

Q. How can I protect the baby birds in a nest from predatory birds and other predators like snakes and cats?

Q. I found a nest near my house and want to observe it but I am worried about disturbing it. Can you give me any advice?

Q. I found a nest with eggs in it and no adult birds seem to be attending to it. I think it's abandoned, or I scared the parents away. What should I do?

Q. What's good nesting material to offer birds?

Q. After birds leave a nest, can I clean out the nest for future use?

Q. I have wasps in my birdhouse. What should I do?

10. Bird Behavior

Q. What do small birds do in a storm?

Q. How do birds survive in very cold temperatures?

Q. Will birds use nest boxes to roost in for warmth during the winter?

Q. I saw a little bird feeding a much larger bird. Is it rare to see two different species feeding each other?

Q. Why do some birds stand on one foot?

Q. A bird keeps flying into my window or car mirror, on purpose. What should I do?

Q. Why do hummingbirds fight so much?

Q. Do birds sleep, and how?

Q. Do birds play?

Q. If Brown-headed Cowbirds are reared by other species, how do they know they are cowbirds when they grow up?

Q. Sometimes I see little birds going after a big bird. Why do they do this?

Q. Why do birds have such elaborate and varied courtship rituals?

11. Bird Trivia

Q. How do you pronounce a scientific name? What's the proper pronunciation for this bird species, Tympanuchus phasianellus?

Q. Where can I find a list of all the birds in the world? And how do I find out a bird's "official" name? For instance, is it "Canada Goose" or "Canadian Goose"?

Q. What is the difference between a beak and a bill?

Q. Are cardinals brighter in winter?

Q. Where did the domestic turkey come from?

Q. What can you tell us about the habitat associations of partridges and in particular whether pear trees are ever involved?

Q. Who is the "Lincoln" that the Lincoln's Sparrow is named for?

 

1. Baby Birds

Q. How long do birds incubate their eggs, and how long do the chicks stay in the nest?

A. The time for incubation varies widely from species to species. You can get this information for any species you're interested in by going to its page in our All About Birds species guide. Once you've found the species you're interested in, click on "Life History" and then scroll down to "Nesting." 

Q. I found a baby bird. What do I do?

Baby birds

Nestlings (left) are mostly featherless and helpless birds that should be returned to their nests, if possible. Fledglings (right) are mobile and well-feathered. Their parents are likely nearby and they rarely need help. (Images via BirdshareAnne Elliot, left; Central Jersey Wildlife, right.)

At some point, nearly everyone who spends time outdoors finds a baby bird—one that is unable to fly well and seems lost or abandoned. Your first impulse may be to help the young bird, but in the great majority of cases the young bird doesn't need help. In fact, intervening often makes the situation worse. Here’s how to determine whether to take action:

The first thing to do is to figure out if the baby bird is a nestling or a fledgling.

Most of the baby birds people find are fledglings. These are young birds that have just left the nest, are still under the care of their parents, and do not need our help. Fledglings are feathered and capable of hopping or flitting, with toes that can tightly grip your finger or a twig. These youngsters are generally adorable and fluffy, with a tiny stub of a tail.

When fledglings leave their nest they rarely return, so even if you see the nest it's not a good idea to put the bird back in—it will hop right back out. Usually there is no reason to intervene at all beyond putting the bird on a nearby perch out of harm's way and keeping pets indoors. The parents may be attending to four or five young scattered in different directions, but they will return to care for the one you have found. You can watch from a distance to make sure the parents are returning to care for the fledgling.

If the baby bird is sparsely feathered and not capable of hopping, walking, flitting, or gripping tightly to your finger, it's a nestling. If so, the nest is almost certainly nearby. If you can find the nest (it may be well hidden), put the bird back as quickly as possible. Don't worry—parent birds do not recognize their young by smell. They will not abandon a baby if it has been touched by humans.

If you have found both parents dead, the young bird is injured, you can't find the nest, or are absolutely certain that the bird was orphaned, then your best course of action is to bring it to a wildlife rehabilitator. A sick, injured or orphaned baby bird may need emergency care until you can get it to a wildlife rehabilitator.

Bottom line: remember that the vast majority of "abandoned" baby birds are perfectly healthy fledglings whose parents are nearby and watching out for them.

Q. If I don't pick up a baby bird, will my cat or dog kill it?

A. It might if it gets the chance. The best thing to do is to keep your pet inside, or leashed well away from the fledgling until the bird is gone. This helpless stage lasts at most a few days, and if you leave the young bird under the care of its parents, it will have a far greater chance of thriving over a lifetime.

Q. Can I raise a baby bird I found?

A. We strongly advise you not to, for two reasons. First, it violates federal and state laws, such as the Migratory Bird Act, to possess any wild native American bird for any length of time without proper permits. Second, even with expert care and feeding, people simply cannot provide baby birds with most of the skills they need to negotiate the natural world.

For excellent, well-reasoned information about the pros and cons of raising baby birds in captivity, visit Dr. Kevin McGowan's webpage, "I Found a Baby Crow." Much of the information about baby American Crows applies to other songbirds as well. 

If you want to give your children wonderful experiences with wild birds, encourage them to spend time helping a local rehabber, bird bander, or researcher.

Q. If I handle a baby bird, will the parents abandon it?

A. It's a myth that parent birds will abandon young that have been touched by humans—most birds have a poor sense of smell, and birds in general identify their young using the same cues we humans do—appearance and sound. It's perfectly safe to pick up a fallen nestling and put it back in the nest, or to carry a fledgling out of danger and place it in a tree or shrub.

Q. I found some abandoned eggs. Can I take them to a rehab center to raise them?

A. Rehabbers almost never incubate eggs. If the eggs have fallen from the nest or been handled by people, the chances are just too great that the growing embryo has been shaken. If the egg eventually hatches, the hatchling is likely to suffer from grave deformities.

Q. Why do birds leave the nest before they can fly?

A. It's to some young birds' advantage to leave the nest as soon as they can. People tend to think of nests as safe, cozy little homes. But predators have a pretty easy time finding a nest full of loud baby birds, and nests can be hotbeds of parasites. Parent birds work from sunrise to sunset every day to get their young grown and out of the nest as quickly as possible. After fledging, the young birds are more spread out, and the parents can lead them to different spots every night, enhancing each one's chances of survival. During this vulnerable time, you can help young birds by making sure your pets are indoors, or closely monitored when outside.

Other young birds may stay in their nests until they are capable of flight. Species such as swallows, woodpeckers, and other cavity nesters nest where there are no nearby branches for young to awkwardly grab onto when they first leave the nest. Unless startled by a predator, young of these species tend to remain in the nest until they are strong fliers.

If you think that a baby bird may have left the nest prematurely, check out our FAQ I found a baby bird. What do I do? for more information.

Q. Do young birds recognize their parents after they've grown up?

A. Most birds do not recognize their family members after their first year. There are exceptions to this, especially among social birds such as cranes, crows, and jays. Canada Geese also remember their parents, and may even rejoin their parents and siblings during winter and on migration.

On the other hand, Black-capped Chickadee fledglings scatter in autumn, and each one joins a different winter flock from its siblings and parents. Mallards and grouse do imprint on their parents, but there is no evidence that they recognize their parents or family members after their first year.

 

2. Sick and Injured Birds

Q. What do I do if I find a sick, injured, or dead bird?

A. If you find a sick or injured bird, contact a wildlife rehabilitator or local veterinarian to see if they are able to care for it. Make sure you call first as some clinics don't have the facilities to isolate sick birds, and can't take the risk of spreading a communicable disease among their other birds. To protect yourself, your family, and your pets, don't handle any potentially sick bird without disposable gloves, and make sure you have a box prepared for it, and a place to bring it, before you put it through the trauma of capture.

If you notice sick birds around your feeders, make sure you clean your bird feeding area. In fact, it is a good idea to regularly clean your feeders even when there are no signs of sick birds: prevention is the key to avoiding the spread of disease. A 10% bleach solution is often recommended and some feeders can even be placed in your dishwasher. If a sick bird does come to your feeder, minimize the risk of infecting other birds by cleaning your feeder area thoroughly. If you see several diseased birds, take down all your feeders for at least a week to give the birds a chance to disperse. And make sure to keep your birdbaths clean. Water allowed to sit for more than a few days can provide perfect breeding habitat for the very mosquitoes most likely to spread West Nile Virus.

If your area is possibly having an outbreak of West Nile Virus or other disease, you may need to report it to your county health department or department of natural resources. To find out, call your nearest game warden or conservation office. Take a look at our West Nile Virus FAQ for more information about what to do if you think you find a bird infected with the virus.

The Cornell Lab of Ornithology's Project FeederWatch web site has additional information on sick birds, including a review of several of the more common diseases that might show up in backyard birds.

If you find a dead bird and are aware of a disease outbreak or you are concerned about health issues, contact your local or county health department or the National Wildlife Health Center. With their permission, you may proceed in collecting or disposing of the dead bird as they direct you to.

Do not pick up the bird without permission, because this is illegal. The Migratory Bird Treaty Act of 1918 protects birds and bird parts (feathers, eggs, and nests) of almost all bird species.

In many cases health departments will not be able to analyze a bird that has already started to decay, so you may be asked to double-bag it and put it in your freezer, or to take it to them immediately. If you do pick up the bird be sure to wear disposable gloves, and wash your hands thoroughly afterward.

If you’re instructed to bring the bird in, remember to record your name and contact information, the date and location, the bird’s species (if known) and a description of the circumstances, including your best guess about the cause of the bird’s death. If you’re instructed to freeze the bird until you can bring it to the facility, double-bag it in plastic, and put the paper with this information between the two layers.

Q. How can I tell if a sick bird has West Nile Virus?

A. It's hard to know without conducting laboratory tests. West Nile virus does affect birds, but several other diseases can be common in birds, too. West Nile virus arrived in North America in 1999. It was first found in New York City and in a few years had spread across the continent. It was extremely damaging to some bird populations, especially members of the crow family (crows, ravens, jays, and magpies).

The disease is spread by mosquitoes, and can affect not only birds but humans as well, usually causing flu-like symptoms. Birds with visible symptoms of West Nile virus often die within a few days. Affected birds will often be fluffed out and stay low to the ground, or seem off balance and unable to stand.

Because West Nile virus affects birds, public health officials look for cases of sick and dead birds as an early warning that an outbreak may begin. Monitoring the disease in bird populations is an important way of tracking the disease. According to the CDC, West Nile virus cases in humans peaked in 2003, declined through the rest of the decade, and then peaked again in 2012.

The Centers for Disease Control has an entire website devoted to West Nile, including a short FAQ about West Nile and birds and a map of West Nile Virus activity.

If you have found one or more dead birds (especially if they are in the crow family), or observed birds that have symptoms consistent with WNV, it may be a good idea to contact your state health department. APHIS has a link to help you find the contact information to report a dead bird in your state. You can also report them to your regional office of the National Wildlife Health Center. For more information please see our FAQ What to do if I find a sick or dead bird?, and please remember that only veterinarians and licensed wildlife rehabilitators are legally allowed to treat wild birds.

In many cases, health departments can't analyze a bird that has already started to decay, so you may be asked to double-bag a dead bird and put it in your freezer, or to take it to them immediately. If you do pick up the bird be sure to wear disposable gloves, and wash your hands thoroughly afterward.

Q. I've seen a sick House Finch with red, swollen, or weepy eyes. What's wrong with it?

A. House Finches with weird-looking eyes are probably afflicted with mycoplasmal conjunctivitis, also known as House Finch Eye Disease. In early fall, the prevalence of this infection increases dramatically, and sick birds may appear at feeders. From 1994–2008 we conducted a citizen-science study of House Finch Eye Disease, and you can still read our FAQ about the disease, its symptoms, and its causes.

There is little evidence that feeders play a direct role in disease transmission, because House Finches are highly gregarious and stay close together near or away from feeders. But to be safe, if you notice sick birds, we recommend that you take down your feeders and clean them with a 10 percent bleach solution (1 part bleach and 9 parts water). Let them dry completely and then re-hang them. Also, rake the ground beneath your feeders to remove old seed and bird droppings. If more than one bird gets sick from this or any other illness, it's not a bad idea to close down your feeding station for a couple of weeks to at least encourage the flock to disperse, to minimize the risk of other birds catching it.

Q. I have a bald bird at my feeder. Is it sick?

A. In fall, we receive many inquiries about bald birds, especially Blue Jays and Northern Cardinals. In late summer and fall, when a bird molts, it usually grows and replaces its feathers gradually, but occasionally a bird loses all the feathers on its head at once. This is particularly true of Blue Jays, many of which molt the feathers of the head, or "capital tract," in synchrony. The result is a very strange looking bald bird! This bald appearance lasts for about a week before new feathers replace the molted ones.

It is possible that in rare cases baldness might be caused by environmental or nutritional factors, feather mites, or lice. To read more and see photos of bald birds, visit the Bald Birds page on the Project FeederWatch web site.

Q. What can cause an adult bird to die inside a birdhouse or nest box?

A. There are a few reasons why adult birds may die in a nest box.

  • If it had obvious injuries, especially on its head, it may have been killed by a House Sparrow or European Starling trying to take over the box. In most cases, though, these competitors toss out birds after they kill them.
  • Was the inside front of the box, below the hole, rough or grooved? Sometimes birds get stuck inside boxes because the inside walls are so smooth that they can't climb out. Tacking sandpaper or small strips of wood, making sort of a ladder, will prevent this in the future.
  • Sometimes an infestation of blowflies or other parasites can become so intense that it kills not only nestlings but also adults. If there was no sign of dead young with the adult, that's probably not the answer in this case.
  • Some wood preservatives may release harmful gases, especially in hot weather. Make sure any paints or varnishes that you use on your nest boxes are rated safe for indoor or playground use.
  • It is also possible that migrants may arrive before adequate food is availble for them to survive. For example, Tree Swallows migrate a long way—some of the birds that nest in northern Canada and Alaska winter down in Central America. If they arrive when the temperature is too cold for flying insects, their primary food, they may die of starvation or hypothermia. This is probably what happened to your swallow, especially if swallows or bluebirds have used your nest box successfully in past years.

Nestwatch, a citizen-science project of the Cornell Lab of Ornithology, has a wealth of information for people who have nest boxes. For features of a good nest box, check out the page, "Resources for Nest-Box Monitoring." You might also like to join Nestwatch and let us know what is happening in your nest boxes.

Q. I've seen a bird with an overgrown or otherwise deformed bill. What is wrong with it?

A. Sometimes birders observe birds with odd-looking beaks. For example, numerous Black-capped Chickadees with greatly elongated and down-curved upper beaks have been reported since 1998 in southern Alaska. The phenomenon has now spread to some 30 species, but seems largely confined at present to southern Alaska. Scientists studying this phenomenon have yet to determine a specific cause. Bird beaks are much like human fingernails—soft structures that grow at a constant rate all the time. Many factors have been implicated in causing beaks to grow abnormally, including disease, parasites, nutritional deficiencies, genetic defects, exposure to extreme heat, exposure to environmental contaminants, and structural damage caused by a collision or other trauma.

A slight malformation may not affect a bird's survival, but an extreme deformity may make normal feeding difficult if not impossible. Sometimes it happens gradually enough that the bird learns to compensate, but if the excessive growth doesn't stop, eventually the bird is likely to starve.

Read about progress in understanding the deformed-beak outbreak in this 2010 Living Bird article.

No matter where you live, if you see a bird with an overgrown bill, it is important to report your sighting so that scientists can track the spread of the phenomenon.

3. Bird Feeding

Q. Should I take my feeder down when the weather starts to warm up?

A. Some people prefer not to feed birds in the spring and summer when there is abundant food. However, leaving your feeders up year-round is not a problem as long as you keep a few things in mind:

  • If bears live near you, you should not keep feeders up during the warmer months. (For example, the New York State Department of Conservation recommends taking feeders down on April 1 in New York to avoid nuisance bears at your feeders).
  • Suet left out in hot weather can soften and foul birds' plumage; or it can become rancid. It's a good idea to take down suet feeders in warm weather. Raw or homemade suet should not be offered in the summer. Some suet manufacturers state that their blocks will withstand temps over 100 degrees without melting; however, these might nevertheless go rancid in short order if extreme high temperatures persist.
  • Bird seed spoils more easily in the heat, especially if it gets wet. If the level of seed in your feeder is not changing, it may be a sign that it has spoiled and birds are avoiding it. You can fix this by changing out your food regularly, or by not filling the feeders as full so that birds empty the feeder more quickly.
  • In extreme heat, you may find that birds will not visit your feeder. Try to find a shady spot for it, and consider putting out a water source (birdbath, slowly dripping spigot) as well.

With respect to the health of birds in your yard, it’s good to remember that the most likely outcome of offering spoiled food is that birds will go elsewhere. In general, birds are hardy, resourceful animals that would no more swallow rancid suet than you or I would make a sandwich with green turkey.

Here at the Cornell Lab, we keep our feeders filled year-round in the Treman Bird Feeding Garden for the benefit of the birds and the pleasure of our visitors. Whether or not you do is up to you.

For more information on bird feeding during the warmer months, check out our blog post, Here’s What to Feed Your Summer Bird Feeder Visitors.

Q. My feeders are being overrun with starlings and blackbirds that eat all the food and keep smaller birds away. What can I do?

A. Deterring some species of birds while attracting others is a perennial challenge for backyard bird lovers. We encourage people to enjoy all the birds that come to their feeders, but sometimes one or more types of birds will wear out their welcome through their insatiable appetites, aggression toward smaller birds, messiness, etc. With the right information and a bit of patience, you can keep frustration and extra expense to a minimum.

  • Pigeons: try to use bird feeders designed to exclude larger birds. Some have "cages" around them that only small birds can pass through; others close off the food source when a heavy bird alights on the perch.
  • Blue Jays, as beautiful as they are, are often unwelcome due to their appetite and occasionally aggressive behavior. They can also be thwarted with feeders designed for smaller birds.
  • Grackles and blackbirds are usually less of a long-term problem, as they tend to visit for a short window of time and then move on. First consider the type of seed you are using. If you're using a seed mix, these are often more attractive to "problem" birds than they are to chickadees, cardinals, goldfinches, and other feeder favorites. Sunflower seed, particularly striped sunflower seed, and safflower seeds, both of which have thick, hard shells, are more difficult for blackbirds to open, so switching to one of those might help.
  • Invasive species such as European Starlings and House Sparrows are often considered “unwelcome” feeder visitors. Because these species are similar in size to many of the more desirable birds, it's a little harder to discourage them. Some people simply remove their feeders for a couple of weeks. Other techniques include keeping food off the ground; and temporarily switching to nyjer seed—sometimes called thistle—in a tube feeder. While starlings and House Sparrows do eat nyjer, both species prefer sunflower seed, and starlings in particular find it difficult to use tube feeders. Starlings have softer bills than most seed eaters, so peanuts (in the shell) and white-striped sunflower seed pose problems for them to open, so you might switch to those items while the starlings are still present.

For more information, visit Project FeederWatch. They offer excellent information on common feeder birds, types of feeders and types of food to help you make sense of the available options.

If you have invasive species nesting in or around your home or out-buildings and they are becoming a nuisance, you may want to evict them from these areas. Try hanging mylar balloons filled with helium so they're floating about wherever the starlings get access. The unpredictable movements of helium balloons and the shininess of mylar often drive birds away. You can close off all access with hardware cloth or other mesh, but mylar balloons are much quicker and easier and work surprisingly often.

Q. What's the best recipe for hummingbird nectar?

A. The sugar content of natural flower nectar varies, and is roughly comparable to sugar water mixtures ranging from a quarter to a third cup of sugar per cup of water. During hot, dry weather, when hummingbirds risk dehydration, it's best to make your mixture no stronger than a quarter cup of sugar per cup of water. But during cold, rainy spells, making the mixture a bit stronger, up to about a third cup of sugar per cup of water, will not hurt your birds and may help them.

Q. Should I use red food coloring in hummingbird food?

A. There is absolutely no reason to add any red dyes to hummingbird sugar water. After all, natural flower nectar is clear, and hummingbird feeders have colorful parts that attract hummingbird regardless of the color of the sugar water.

Sheri Williamson of the Southeastern Arizona Bird Observatory (SABO), and author of A Field Guide to Hummingbirds and Attracting and Feeding Hummingbirds, writes, "The bottom line is that ‘instant nectar’ products containing artificial coloring are at best a waste of your hard-earned money and at worst a source of disease, suffering, and premature death in hummingbirds."

Q. Why do I see fewer hummingbirds in midsummer?

A. Adult male hummingbirds aggressively defend their territory, and if your yard is within the territory of one, he may drive all other male hummingbirds away during the nesting season.

If you have a nesting female nearby, she will visit your feeder only periodically, spending most of her time incubating her eggs. After the eggs hatch, she usually concentrates her feeding at flowers that supply tiny insects as well as nectar—insects contain the protein that her nestlings need in order to grow. Once the young have fledged, she continues feeding them for several days until the fledglings have mastered getting their own food. At this time, she may bring them to your feeders to teach them how to take advantage of this easy food supply, too. This is also when males begin migrating, with adult females soon following. So many of the hummingbirds that suddenly appear are actually migrants from farther north, just passing through.

Q. Should I stop feeding birds in fall so they can start their migration?

A. Keeping your feeders up has no influence on whether a bird will start its journey south. A number of factors trigger the urge for birds to migrate, and the most significant one is day length. As days grow shorter in late summer, birds get restless and start to head south, taking advantage of abundant natural food, and feeders where available, to fuel their flight.

Hummingbirds are no different from others and will migrate regardless of whether feeders are kept up. However, we encourage people to keep feeders up for several weeks after the last hummingbird leaves the area, just in case a straggler shows up in need of additional energy before completing the long journey south.

Q. A hawk has started hunting the feeder birds in my yard. What can I do?

A. Hawks that feed on birds apparently take the term bird feeder at face value. If you want to discourage the hawk, you'll have to take your feeders down for a few days, until the smaller birds disperse. In the wild, birds face constantly fluctuating food supplies, so songbirds, doves, and hawks alike will know to search for food elsewhere. Put your feeders up again in a week or two. If you're lucky, the songbirds and doves will quickly return but the hawk will have found hunting grounds somewhere else. You can learn more about feeder problems and solutions at our Project FeederWatch web site. 

Q. What should I do if I find algae in my birdbath?

A. Scrub your birdbath immediately if algae start to grow. Use very hot water and a good scouring brush.

Water in birdbaths should be changed at least every three days, and in warm weather even more often. Algal growth is one issue, but even more urgent and potentially dangerous is the possibility of mosquitoes breeding. The mosquitoes that breed in small stagnant pools, such as rain gutters and birdbaths, are the ones most likely to harbor West Nile Virus, which is dangerous for both humans and birds. The importance of keeping water in birdbaths clean cannot be overemphasized.

Also, providing an aerator or a slow drip from an overhanging bottle will attract a wider variety of birds to your birdbath.

Q. I’m seeing fewer birds in my yard. Is something affecting their populations?

Bird populations fluctuate seasonally and from one year to the next for a range of reasons. Often when someone reports that birds have gone missing from their yard, they are just seeing normal variation. Causes for these regular changes include:

  • Fluctuating food supplies/requirements. Cones, berries, seeds, and insects change from year to year, causing birds to move about to take advantage of food surpluses and to escape from areas with food shortages. Also, birds have different dietary needs during different times of the year, so they may move to or away from your feeders seasonally.
  • Weather patterns. Birds may temporarily move out of areas to avoid droughts, floods, storms, exceptional heat and cold waves, and other unusual weather conditions.
  • Predator populations. Foxes, birds of prey, cats, and other predators have fluctuating populations too. When their populations are high, bird populations may fall. This can also happen on a very local scale, such when a hawk takes up residence in your yard. When the predators move on, your birds will come back. Here’s what to do about a hawk in your backyard.
  • Disease. On rare occasions, outbreaks of diseases can sharply reduce numbers of certain birds. Examples include the effect of West Nile virus on crows in the early 2000s; House Finch eye disease; and salmonellosis on feeder birds. Learn more about diseases and how to keep your feeders clean.
  • Habitat change. Tree removal, housing developments, land clearing, fires, and other changes can change the number or types of birds you see.

On the other hand, we know that many populations of bird species are in fact declining consistently from year to year. The North American Breeding Bird Survey estimates how much species’ populations have changed since the mid-1960s. In 2010, Partners In Flight compiled a list of Common Birds in Steep Decline—42 species that have lost 50% or more of their population since the 1960s. You can also refer to their full database on conservation status of North American landbirds.

Since it is difficult for scientists to monitor birds on a continent-wide scale, science has turned to bird watchers for help via the emerging field of citizen science, which brings together thousands upon thousands of individual observations into centralized databases.

Projects such as NestWatch and FeederWatch focus on gathering information on birds during breeding and winter feeding times respectively. A new project, YardMap, seeks to add another layer of data to bird observations by allowing people to map the habitat in their yards.

And one of the biggest citizen science efforts ever undertaken, eBird, allows people anywhere in the world to enter bird observations anywhere, anytime, into a worldwide database. eBird also allows you to record and organize your bird sightings, use maps to view real-time sightings of particular species , create charts detailing which birds are seen in your area, and when, and make graphs to compare species occurrence for an area over a period of up to 5 years.

Through these efforts, we are learning more than ever before about many basic questions: Where does a given species live? How abundant is it? How are these patterns changing with time? With a clearer understanding of these baselines, we are in a better position to analyze the underlying factors that are acting on bird populations, and chart courses of action for their benefit.

Q. I live in a high-rise apartment in the city. How can I attract birds?

A. Your first step will be to set up feeders. To begin with, use small feeders so your seed doesn't spoil before you get any "takers." Try one hanging feeder for nyjer seed and one for sunflower seeds. We recommend suction cup feeders that can be set right on the glass—you dramatically reduce the likelihood of local birds colliding with glass when the feeders are on the glass or set up within just 3 feet of the window.

Once the feeders are in place, try playing recordings of cardinal and House Finch calls and songs (at a normal volume, so that nearby birds may think there's a well-fed bird up there and go join it). You may keep playing recordings through spring and summer, until birds figure out that your terrace is a good place to feed.

In May, you can try hummingbird feeders—the color red may draw some birds in to your feeders. Again, use fairly small feeders at first, and change sugar water at least every couple of days in hot weather or if feeders are in direct sunlight, and every 2-4 days when it's cooler and feeders are shaded.

Depending on what the habitat below you is like, it may take some time for birds to discover your balcony. Bird feeders in high-rises along lakes and rivers are fairly likely to be discovered during migration. Feeders in any neighborhood are more likely to attract birds if there are trees and other vegetation at ground level, and the more plants on your balcony, the more likely curious birds will check it out. Providing food and nectar-producing plants may lure birds in, and will make your balcony more pleasant for you whether or not they ever arrive. Putting up a hanging plant or two will improve your chances of a pair of House Finches nesting. Make sure baskets are set close to the window rather than on the outer edge to reduce the chances that a nestling's first venture out of the nest won't be its last.

Explore more of our tips about attracting birds to your yard, what to feed them when they get there, and check out our Celebrate Urban Birds project for information on attracting birds to city yards and urban balconies.

Q. Do birds store food for the winter?

A. Chickadees, nuthatches, some woodpeckers, jays, and crows store, or "cache," food. Many other feeder birds—doves, sparrows, blackbirds, finches, etc.—do not store food at all.

Do you report your birds to Project FeederWatch? It can be really fun, sharpen your observation and identification skills, and give you a chance to provide valuable data for scientists. Project FeederWatch runs from November through early April. Check it out and sign up!

Q. What are owl pellets?

A. Owls swallow their prey whole or in large pieces, but they cannot digest fur, teeth, bones, or feathers. Like other birds, owls have two chambers in their stomachs. In the first chamber, the glandular stomach or proventriculus, all the digestible parts of an owl's meal are liquefied. Then the meal passes into the second chamber, the muscular stomach or gizzard, which grinds down hard structures and squeezes the digestible food into the intestines. The remaining, indigestible fur, bones, and teeth are compacted into a pellet which the owl spits out. Owls typically cast one pellet per day, often from the same roosting spot, so you may find large numbers of owl pellets on the ground in a single place.

Browse through owls—and listen to their hoots—in our bird guide.

Q. How do I keep ants out of my hummingbird feeder?

A. Many hummingbird feeders—especially the saucer variety—have a center "moat" separate from where the sugar water is placed. These feeders are easy to keep ants out of by filling that moat with water. The ants that do get down into it drown, but usually just don't even try. If you have another kind of feeder, make sure it's hanging by a simple rod rather than string, and coat a center spot all around, about an inch wide, with petroleum jelly. The ants won't cross that.

We've got more tips about how to get the most out of bird feeders in our Attract Birds section.

Q. How do I keep the squirrels in my yard away from my feeders and bird seed?

A. We'd like to tell you that there's a foolproof way to defeat squirrels, but the truth is that it's very hard to make a feeder completely safe from these voracious little critters. Plenty of strategies have been tried—and many of them do offer some relief in some situations. A while ago we asked our Facebook visitors to tell us what works for them and we boiled down the result into our Top Nine Squirrel Intervention Suggestions: obstruction, elevation, isolation, lubrication, combination, altercation, innovation, separation, and capitulation.

In general, the three best approaches include

  • putting your feeder in a place squirrels can't get to (not always possible in all yards)
  • using a feeder designed to keep squirrels away from the seed
  • providing food specifically for the squirrels, such as cracked corn, to keep them away from your feeders

Other approaches include making it hard for squirrels to climb up to your feeder, putting additives such as capsaicin (hot pepper) that birds can't taste into your bird seed mix, and—what may turn out to the best suggestion—trying to enjoy the sight of squirrels in your yard!

For more details and caveats on each of these suggestions, check out the Attract Birds section of All About Birds. And for a glimpse at just how resourceful squirrels can be—even as they interfere with one of our research projects—read this former student's account of her battle with squirrels.

4. Bird Identification

Q. What's the best book or field guide for bird identification?

A. The "best" bird identification book is often a matter of choice, so different people will give you different answers. You may want to start by browsing field guides at a library or bookstore to get a sense of which one works the best for you. Chose a few that are appealing and look up four or five familiar birds. Which guide portrays these birds closest to the way you see them? Is the book comfortable to use? Are the birds easy to find in its pages?

Most experienced birders prefer a field guide with drawings by an expert rather than with photographs. Good bird artists portray birds in similar poses, using their experience and knowledge to make it easier for you to key in on the important field marks. With photographs, lighting conditions and differences in bird postures can obscure important features or highlight unimportant ones, although the photos in some well-done guides are digitally manipulated to make color comparisons among different species more accurate.

You may also want to consider size when buying a field guide: if your book is too large, you won’t want to carry it in the field, but if it’s too small, it may not include all the birds you’re likely to see in your area. If you hope to eventually become proficient at birding, it’s wise to start with a guide that shows all the birds of North America or at least all the birds of the East or the West.

Hawaii’s Birds, a small guide published by Hawaii Audubon, is the only field guide with complete coverage for a single state. Other than that, small-geographic area or state-focused guides do not include all the birds found in a given area. These are more minimalist types of guides that should be used in conjunction with a more thorough guide to avoid misidentifications and frustration.

The guides most often recommend by the Cornell Lab's staff include:

  • The Kaufman Field Guide to Birds of North America. This field guide was specifically designed for beginning birders. It uses photographs of birds, but with a layout more typical of field guides using paintings, allowing easy comparison of related species.
  • The Peterson Guide to the Birds of Eastern and Central North America, or The Peterson Field Guide to Birds of Western North America. Covering just half the continent, these classic guides help you narrow down your choices to the birds where you live. Unfortunately, the range maps are all in the back of the book. You may think you've pinned down the identification of a bird you see in Seattle only to discover, weeks later when perusing the maps, that that species is found only in Arizona.
  • The Sibley Guide to Birds focuses on plumage, is very detailed, and includes excellent drawings of birds in different plumages. Because it provides so much detail, fewer species are shown per page, making comparisons a bit more difficult. The original is quite large and heavy, but there are two much smaller versions, The Sibley Field Guide to Birds of Western North America and The Sibley Field Guide to Birds of Eastern North America, that are equally complete (for each half of the continent) and far more portable.
  • The Golden Guide's Birds of North America, is extremely portable and accessible for beginners.
  • National Geographic Field Guide to the Birds of North America is very popular and accessible, but a bit large. The illustrations were done by a variety of artists, so there isn't the single style found in the Peterson, Sibley, or Golden guides.

Once you become more familiar with the birds you're seeing, you'll find the All About Birds Online Bird Guide a wonderful reference for more information about each species as well as for photos and sounds of the birds.

Q. I saw a black-and-white bird at my feeder with a red triangle on the breast. What is it?

A. We always know spring is here when we get this question. It means the Rose-breasted Grosbeak is migrating north. We follow its migration as emails arrive, first from Florida and then a few days later from South Carolina or Tennessee. Take a look at the All About Birds Online Bird Guide and you'll learn more about this beautiful migrant.

Q. Yesterday evening around dusk I watched hundreds and hundreds of birds flying over my house. What were they?

A. That depends on what they looked like! They could have been blackbirds, grackles, cowbirds, crows, nighthawks, robins, or any other number of species that flock. At the end of summer, when birds finish breeding, many species become more social and join flocks. In the evening, hundreds of them may travel toward roosts and spend the night together.

Q.: There's a bird in my yard I've never seen before. How can I find out what it is?

A. There are four key features for visual identification. While looking at an unfamiliar bird, observe:

  • Size and shape
  • Color pattern
  • Behavior
  • Habitat

Birders try to take notes about these four features, and some sketch or photograph the bird as well to help make an ID.

How does this tell us what the bird is? By looking at the bird's shape, we can get an idea of what family it belongs to. Might it be a duck? A woodpecker? How is the bill shaped? Long or short, stout or thin, straight or curved?

If another bird is nearby, we look at relative sizes. Is our bird sparrow-sized? Smaller than a robin? Larger than a crow? And we look at the shape and size of various features, compared to other features on the bird itself. Are the wings long? Do they extend to the tip of the tail? Is the beak long compared to the bird's head size?

Then we look at overall colors and special patterns. Does it have wingbars? An eye-line? Streaking on the breast or back?

We're also paying attention to the bird's behavior. Does it walk or hop on the ground? Flit out from a tree, grab a bug and flit back? Is it visiting a feeder? Is it alone or feeding with other birds? If it vocalized, what did it sound like?

Habitat is also important. Is the bird in deep forest, expansive prairie, open woods, a marsh or swamp? Your location will also be an important clue to help rule out bird species not found in your region during that time of year.

Now look in a field guide and try to find your bird. This can seem exceptionally frustrating when you're just starting out, and often your bird will disappear before you've even come to the right page. That's where taking notes can help.

If you have some guesses about your bird's identity but still aren't sure, take a look at the All About Birds Online Bird Guide for additional clues about appearance, behavior, and sound.

Even if you don't find this bird, don't get discouraged. Little by little, you'll learn various species, and every time you search through your book you'll grow a little more familiar with where the different species are grouped, making you quicker to find the next one.

Q. The goldfinches at my feeder are starting to look dull and patchy. What's happening to them?

A. Your goldfinches aren't sick—they're molting. Every summer, goldfinches replace their bright body feathers with duller ones for the winter. The new feathers come in one by one, giving the birds that strange patchwork appearance.

Unlike most songbirds, goldfinches molt twice a year. At winter's end, they'll grow in a complete set of new golden yellow feathers. Again each one will have a strange, patchy appearance for a few days, but soon they'll be vividly beautiful again.

Q. I saw a House Finch that was orange or yellow instead of red. What happened to it?

A. Male House Finches are generally red, but under certain certain circumstances they may be orange or yellow instead. Different subspecies may show color variations, but differences in color are also attributed to diet. When a bird is molting, its diet will determine the colors of its new feathers. If a diet lacks certain pigments, then a House FInch may end up orange or yellow instead of its usual red. Project FeederWatch participants often keep track of interesting birds, including those with unusual color patterns. Read more about House Finch color variations on the FeederWatch website.

Q. What can cause birds to show weird color variations, such as being all or partly white, or unusually dark?

Some individual birds may look quite different than they appear in field guides. Often, there's a very simple reason behind this: the bird is molting. For example, when American Goldfinch molt between their showy spring and summer plumage and their more drab winter plumage, they can look very unusual during the transition period. But birds, like other animals, can also exhibit naturally occurring color and pigment variations that can make ID difficult. For example:

  • Albinism can cause both true albinos and partial albinos. Albinism usually results from a genetic mutation that interferes with production of the pigment melanin. True albinos are rare in nature because without protective pigments in the eyes, these birds quickly become blind. Also, feathers wear out more quickly without pigments to provide structural support. Partial albinos are much more common, and most birders eventually see at least a few of these individuals. Partial albinos have a pied appearance with usually irregular patches of pure white feathers. This form of albinism usually occurs during development, but may also happen after an injury when new feathers lack pigments. Some birds also develop stray white feathers as they age.
  • Leucism is another plumage aberration caused by changes in pigments; leucistic birds are exceptionally pale all over. They produce smaller amounts of pigments in all their tissues, making the entire plumage look washed out while not being pure white. Plumage patterns typical of the species, such as a mask or wingbars, often remain detectable.
Examples of partially albino and leucistic birds

Examples of white and partly white versions of common birds: Red-tailed Hawk by madglads, Canada Goose by Laura Erickson, and Black-capped Chickadee by Philip McCormack.

  • Melanism causes birds to have an excess of dark pigmentation and is generally caused by a genetic mutation, but can also be a result of certain diets. Some species have a naturally occurring melanic form (or "morph"), such as the Red-tailed Hawk.
  • Xanthochroism is a condition where individual birds of a given species may have yellowish or orange plumage instead of red. This may be caused by a genetic variation or by diet. House Finch are often reported as exhibiting xanthrochroism.
  • Erythrism is condition where some individuals appear more reddish or rufous than others of their kind. For example, Eastern Screech-Owl and Ruffed Grouse often display erythrism and have commonly occurring rufous individuals. This condition is also caused by a genetic mutation or by diet.

If you think that you see an individual of a certain species, but the color isn't quite "right," keep these variations in mind and remember that size, shape, and behavior often help to identify a bird even when its plumage looks odd. Comparing the shape of a strange bird with other birds nearby can be very helpful as individuals often flock with others of their species.

Visit FeederWatch's Unusual Birds page to learn more about color variations in birds.

Q. Why are some species found out of their normal range more than others?

A. Some species wander more regularly than others. Many winter finches, such as crossbills and Pine Grosbeaks, may arrive en masse in response to scarce food in their northern homes. Snowy Owls may wander south when the population of their favored food, lemmings, plunges. Irregular migrations such as these are termed irruptions.

Migrating birds may be blown off course by the strong winds of hurricanes and other violent storms, or grounded by fog, heavy rain, or other adverse weather conditions.

Some birds, often juveniles, disperse northward after the breeding season in what is referred to as post-breeding or vagrant wandering. This is especially common with some herons and ibises.

Occasionally birds appear in new areas by migrating in a direction opposite to that expected, referred to as reverse migration. One theory to explain this is that their internal navigational system is malfunctioning. This may explain sporadic appearances of Fork-tailed Flycatchers in North America.

Individuals of some species, particularly western hummingbirds, wander east/southeast during autumn. No one has teased out exactly why this seems to be happening more often in recent decades than in the past.

Remember that range is a dynamic concept, and species' ranges change over time, albeit usually quite slowly. Tufted Titmice and Northern Cardinals, for instance, live much further north than they did 100 years ago.

Q. What should I do to report a rare bird?

A. If you are fortunate enough to see a rare bird, you should take careful notes about what you see, describing plumage color patterns, beak shape, eye color, behavior, habitat, vocalizations, and any other features that will aid in identification. Draw a sketch of the bird noting any distinctive characteristics or, better yet, try to take a photograph or video of the bird in action. If you're inexperienced at documenting rare birds, you might want to call a trusted, more experienced birder to see if she or he can confirm your sighting. Your careful documentation of this bird will help you build your skills and also ensure that your report becomes part of the scientific record.

Once you're absolutely certain of its identification and have written down your documenting description, Report it to your local bird club, Rare Bird Alert, or Audubon chapter, and make sure to report it on eBird. Don't feel defensive if you're questioned about all the details. It is essential for official records to be accurate, and the overall feeling is that it's best to leave out some legitimate sightings that aren't well-enough documented than to include some inaccurate ones. Virtually every birder has had at least one sighting rejected by a state organization. This is not a commentary on your birding skills or a judgment of what you've really seen, but simply a conclusion, usually by a committee, that there is at least a remote chance that your bird may have been something else. Usually their findings will be very helpful in teaching receptive birders (and not just the one whose report was rejected!) what features to look more closely at, and what other possibilities to take into account when documenting a rare bird.

Q. What are some ways to enjoy birding on a budget?

You can have years of enjoyment with excellent binoculars costing less than $300 that will allow you to identify as many birds as those top-of-the-line ones. Check out the models included in our 2013 Best Binocular Review. Investing $30 in a field guide can provide a lifelong reference for learning about hundreds of birds in your own area and anywhere else you may go in North America. And birding locally can provide endless enjoyment and excitement as you hone your skills and continually learn more about the diversity and behavior of birds.

Read more about birding on a budget in BirdScope.

Q. How can I adjust my binoculars so I see a good image without blacked-out areas?

A. Considering how expensive binoculars can be, it’s odd that most companies don’t include operating instructions in the package. Using binoculars is like riding a bike —wonderfully easy, once you have the hang of it.

Before you try to see birds through your binoculars, you need to make a few adjustments. Virtually all binoculars have several helpful features that allow them to be tailored to different users. The eyecups hold the ocular lenses (the lenses you look through) exactly the right distance from your eyes (this distance is called eye relief), to optimize magnification and cut out peripheral light, making the image clearer and brighter. Extend the eyecups if you don’t wear eyeglasses. Since eyeglasses hold binoculars away from the eyes and let in peripheral light anyway, retract the eyecups if you do wear glasses.

Next, set the barrels of the binoculars to match the distance between your eyes. Looking through them, adjust the barrels until you have a solid image through both eyes. If the width isn’t set properly, your image will black out.

Virtually all binoculars on the market have center focusing, in which a single knob or lever controls the focus for both eyepieces simultaneously. Our eyes are seldom precisely matched, so to accommodate the difference between our two eyes, binoculars also have a diopter adjustment near the optical lens on one side or the other, or as part of the center focus knob. Diopter adjustments are normally numbered from +2 to –2. Here’s how to adjust the diopter so you can use your binoculars without eyestrain:

  1. First find the diopter adjustment and set it at zero.
  2. Find something a good distance away that has clean lines. A sign or something else with letters or numbers is often a good choice.
  3. Cover the objective lens (the large outside lens of the binoculars) with the lens cap or your hand on the side controlled by the diopter adjustment, and then focus on the sign using the center focus knob. Try to keep both eyes open as you do this.
  4. Switch hands, uncovering the lens with the diopter adjustment and covering the other lens. Focus again, this time using the diopter adjustment, not the center focus.
  5. Repeat a couple of times to make sure. After you’re done, your sign should be crisply focused through both eyes.
  6. Notice the number setting on the diopter adjustment. Sometimes during normal use, the adjustment knob may get shifted, so every now and then when you start using them, check to make sure it’s set where it should be for your eyes.

Finally, make the neck strap as short as it can be while still allowing you to use the binoculars comfortably and put them over your head easily. The longer the strap is, the more the binoculars will bounce, and the greater the chance you may bonk them against rocks, tables, and other objects whenever you bend down.

If you're new to birding, watch our free how-to video series, Inside Birding, to get started on identifying birds with confidence.

Q. I've just upgraded my optics. What should I do with my old binoculars?

A. Many birders keep their old optics on a closet shelf just in case anything happens to their new ones. As insurance, this isn’t a bad idea, but if your old optics are in usable condition, you may want to put them to work so that others can enjoy birds and protect their future. How? Donate your old optics to a local nature center or birding club, or to an organization such as the American Birding Association’s Birder’s Exchange, or to Optics for the Tropics. Both organizations send used (and sometimes new!) binoculars to researchers and educators in Latin America and the Caribbean.

Q. I often see birds on telephone wires while I’m driving—how do I figure out what they are from such a short glimpse?

A. Quickly identifying a mystery bird requires a familiarity with size & shape, color pattern, behavior and habitat. These are the basic four keys of bird identification, and they can make it possible to identify a bird with just the briefest of sightings. We’ve got several ways to help you practice:

  • Visit our Building Skills pages for a step by step introduction to each of the four keys of identification.
  • Watch our free Inside Birding videos and let expert birders Chris Wood and Jessie Barry demonstrate the finer points of the four keys for you.
  • It also helps to keep a running list in your head of which birds are most likely in your location and time of year. Our eBird project is great for that—use the Bar Charts function or explore recent sightings using the maps.
  • If you want to delve deeper, check out our low-cost Be a Better Birder tutorials, filled with info, tips, and interactive quizzes and games.

Now: how do you put your knowledge into practice? Let’s imagine it’s early October, and you are on the road somewhere outside Chicago. From the passenger’s seat you see a bird perched on a telephone wire. You note: Robin-sized, buffy color, long tail, round body, small head. Your curiosity is piqued, but the moment has passed.

First, let’s assemble that running list of birds likely to be on a telephone wire in the Midwest: American Kestrel, European Starling, Mourning Dove, Rock Pigeon, Eastern Bluebird, American Robin, Red-winged Blackbird, House Finch, various swallows…. these are the usual suspects.

Based on the size we can eliminate the larger pigeon, and the smaller House Finch and swallows. The long tail rules out starling, bluebird and robin. The color is wrong for a blackbird. That leaves American Kestrel and Mourning Dove. You noted the body was round and the head small (like a dove) rather than slender and blocky headed (like a falcon). Though you may not be able to be 100 percent certain, Mourning Dove is looking more and more likely.

The reality is, when identifying a bird from a moving vehicle you may never be 100% certain what you are looking at. And please remember to do your road birding from the passenger’s seat, letting the driver concentrate on the road. By applying these basic identification skills you can make a very well-educated guess. Good luck!

5. Migration

Q. Do hummingbirds migrate in flocks?

A. Hummingbirds migrate individually. When a late October straggler in the East is a Ruby-throated Hummingbird, it's usually an immature bird from further north whose mother got a late start with that nest. Ruby-throated Hummingbirds are strongly migratory, but their bodies need a high level of fat to fly long distances. As people bring in their feeders in fall and frosts kill nectar-bearing flowers, those hummingbirds remaining have to go long distances between feeders, so yours may remain for a week or two before its body is replenished enough to continue. Hummingbirds are surprisingly hardy as long as they can get enough food each day, and they need extra calories during cold spells.

Oddly, many of the hummingbirds that turn up at Eastern feeders late in the season aren't Ruby-throated Hummingbirds at all! For some reason, more and more Rufous Hummingbirds from the West are heading southeast instead of directly south to Mexico. Believe it or not, one of these turned up in my northern Minnesota backyard on November 17, 2004, and remained for over two weeks! And sometimes tropical hummingbirds such as Green Violetear turn up at feeders in the U.S., often in fall. So look carefully at yours just in case, and keep the food fresh. When it's cold, it's not a bad idea to up the concentration of sugar to 1/3 cup per cup of water to give it more calories, which they burn while shivering.

Tragically, some of these stragglers do end up dying, but your feeder really isn't keeping your hummingbird from migrating. Rather, your feeder is giving it its best chance to restore its body to continue on.

Q. How do hurricanes affect migrating birds?

A. Each year, migratory birds cross the Gulf of Mexico during hurricane season. Most birds wait for favorable winds and weather before starting a migratory flight, so seldom strike out over water during a hurricane, but some birds may be well offshore when a storm begins. Although migrants have enough fat (fuel reserves) to make the 600-mile Gulf crossing in favorable winds, they may not have enough energy to survive if they have to fight against headwinds.

Before and after flights, when migrants have higher than normal food requirements, they may have problems finding safe supplies of food in areas devastated by storms. Resident birds in hurricane areas also suffer when their food supplies, such as fruits and berries, are stripped from trees and shrubs. Like migrants, they may wander to other areas in search of food. Preserving critical coastal habitats is essential for these birds. It's also crucial for them that we enforce strict regulations to prevent hazardous materials from leaking or spilling during storms and floods.

Large storm systems may drive some birds far off-course. Strong-flying birds often move ahead of the storm, carried by the winds at the forefront of the weather system. Brown Pelicans, Magnificent Frigatebirds, and other oceanic birds have been recorded far inland, sometimes more than a thousand miles from the coast, after hurricanes. Some of these birds may find their way back; others, unable to deal with the unfamiliar terrain or to find appropriate food in freshwater, may die.

Birds and hurricanes have coexisted for millennia, and given the chance, healthy bird populations rebound from the effects of such natural disasters. Unfortunately, humans make this difficult for some birds because we have destroyed so much natural coastal habitat, and so nowadays hurricanes pose greater threats to vulnerable bird populations than they once did. Working to preserve and restore as much coastal habitat as possible, to minimize toxic spills and leaks during storms by enacting and enforcing strict regulations, and to keep bird populations healthy year round are our best strategies for minimizing the long-term effects of hurricanes on birds.

For a more detailed discussion about hurricanes and birding in and around them, check out eBird's Hurricane Birding—an eBird Primer in the second part of eBird's article on Hurricane Irene (2011). You may also be interested in Storm Birding: Hurricane Arthur, and Hurricane Sandy—a dangerous (and intriguing) storm!.

Q. Is it unusual to see American Robins in the middle of winter?

A. We do get a lot of questions from people surprised by seeing American Robins in winter. But although some American Robins do migrate, many remain in the same place year-round. Over the past 10 years, robins have been reported in January in every U.S. state, except Hawaii, (see map) and in all of the southern provinces of Canada.

As with many birds, the wintering range of American Robins is affected by weather and natural food supply, but as long as food is available, these birds are able to do well for themselves by staying up north.

One reason why they seem to disappear every winter is that their behavior changes. In winter robins form nomadic flocks, which can consist of hundreds to thousands of birds. Usually these flocks appear where there are plentiful fruits on trees and shrubs, such as crabapples, hawthorns, holly, juniper, and others.

When spring rolls around, these flocks split up. Suddenly we start seeing American Robins yanking worms out of our yards again, and it’s easy to assume they’ve “returned” from migration. But what we’re seeing is the switch from being nonterritorial in the winter time to aggressively defending a territory in advance of courting and raising chicks. This behavioral switch is quite common in birds.

You can report your robin sightings (and any other birds you see) at eBird. Read more about American Robins in our All About Birds Species guide.

Q. Do backyard birds return to the same spot year after year?

A. Many migratory songbirds return to the same local area, and often to the exact same territory, each spring, even after traveling thousands of miles to and from their wintering grounds. Migratory songbirds tend to have short lives (annual mortality rates are about 50 percent), but birds that survive their first winter to breed in your yard have a higher chance of surviving year to year. Studies of banded birds show that 20-60 percent of migratory songbirds are likely to return to the same local area at least two years in a row.

Q. How do birds prepare for long migrations?

A. As days shorten at summer’s end, photoreceptors in their brains trigger hormonal changes that stimulate many birds to molt into new feathers that will stand up to the rigors of a long flight. Their hormones also trigger a huge appetite, and they start eating voraciously, gaining significant amounts of weight. Many insectivorous species supplement their diet with fruits, grains, and other items that can be converted to body fat, which birds burn efficiently for energy. These hormonal shifts make birds increasingly restless, especially at nighttime. Suddenly, one day it’s time to go!

Q. Can you really use weather radar to see migrating birds?

A. It's true. Weather radar images show where radar beams have been "reflected" as they sweep the atmosphere. They're useful for showing weather conditions because the beams are reflected by precipitation and the water vapor in clouds, but they can also be reflected by swarming masses of birds or insects.

In the early days of World War II, British radar operators noticed mysterious, ethereal shadows drifting across their screens. They weren't associated with weather systems and so the radar technicians nicknamed them "angels." In 1958, a New Orleans high school student named Sidney Gauthreaux, realizing that these "angels" were really the radar reflections of swarms of birds, started scrutinizing radar images. As a Louisiana State graduate student, he worked with radar images to document the existence of massive trans-Gulf migrations. In the late 1980s, Gauthreaux started examining archival radar images and made a disturbing discovery: major bird movements over the Gulf had declined by nearly half since the 1960s.

Next Generation Radar (NEXRAD) made studying bird migration much easier. The Air Force started using it to avoid collisions in their Bird Aircraft Strike Hazard program. Graduate students took stunning images of giant expanding aerial doughnuts, which they found to be thousands of Purple Martins radiating from critical roosting sites each morning. Now it's easy for anyone with access to a NEXRAD weather map on their computer to see birds take off on migratory movements at night or alight in the morning, if you know how to interpret the mystifying patterns. You can learn how at Gauthreaux's website at Clemson University.

Q. Is it possible I've heard a whole flock of swans migrating overhead late at night?

A. Swans, geese, and ducks migrate both by day and by night, so it's quite likely you were hearing swans. Most songbirds migrate by night as well. Standing outside listening is a wonderful way to appreciate the magnitude of nocturnal migration.

You can also view the magnitude of a night's migration using NEXRAD weather radar. If you're interested, Braddock Bay Bird Observatory offers a good example of using radar to see bird migration. Try this site to learn how to identify flight calls of nocturnal migrants. Or just train your spotting scope on the full moon and see how many birds pass by!

Q. There's a hummingbird at my feeder in the dead of winter. Will he be okay?

A. Hummingbirds are remarkably tolerant of cold weather, so it’s likely your bird will be fine if it can continue to find food. Individuals of a few hummingbird species, most often Rufous but also some Allens, Anna's, and others, have been wintering further north in recent years. Reports of Rufous Hummingbird from December 2012 and January 2013 include Michigan, upstate New York, Massachusetts and Indiana!, and Anna’s Hummingbird regularly winters as far north as British Columbia. You can get an idea of where hummingbirds have been found in winter by looking at maps from eBird, like this one of Rufous Hummingbird.

For reasons still not well understood, more and more of these birds are surviving the entire season even in more northerly areas.

Birds of all species, whether rarities or right in the heart of their wintering range, do die over winter, but as long as they have reliable food sources they have a reasonable chance of surviving well into the season. Some have even returned to the same feeders from one winter to the next.

Q. Where can I go to watch hawk migration?

A. Few spectacles are as exciting as witnessing a big hawk migration—and each fall brings another chance. And you don’t have to visit one of the famous migration spots such as Hawk Mountain in Pennsylvania and Hawk Hill in San Francisco—it’s possible to enjoy this phenomenon from many spots closer to home. You just need to find a good view and pay attention to weather patterns.

Being at the right place on the right day during hawk migration can be a transcendent experience in which hundreds, perhaps thousands of raptors pass by. Bear in mind that migrating hawks follow well-defined routes as they move south, generally moving from northwest to southeast (east of the Rockies), so you’ll want a clear view to the north or northwest. Most hawks are soaring birds. They depend on thermals and updrafts to help them travel. and this means they often follow ridgelines. They also tend to follow shorelines so that they avoid crossing large bodies of water where updrafts and thermals are scarce.

In the fall, the best time to observe hawk migration is often the second day after a cold front has passed. This is especially true if there are steady northwest or west winds producing updrafts as the strong air currents are forced over the north-south oriented ridges.

Thanks to our BirdCast project it’s easier than ever to be in the right place at the right time. The project is a collaboration between ornithologists and computer scientists. It produces free, weekly forecasts about which birds are likely to be migrating across which regions of North America. Additionally, the Hawk Migration Association of North America has a map of hawkwatch sites for each state.

So find a hilltop, open area, or shoreline with a clear view to the north or northwest. Watch the weather or determine when a cold front will be passing through. Wait one day, and if the forecast for the following day is sunny and breezy, head to your spot and give it a shot!

Q. I thought geese migrated south in the winter and north in the summer. Why did I just see a flock of Canada Geese flying in the "wrong" direction?

A. There are several possibilities, but at this time of year it's likely that these are family groups moving around, now that the yearlings can fly, in search of feeding grounds.

Canada Geese raise their young near water, where the goslings can feed and if necessary dive or swim away to escape predators. In late summer the adults temporarily become flightless for several weeks as they molt their wing feathers. Once the young have learned to fly, and the parents have regained their flight, the whole family will take off from their nesting grounds to find more productive feeding areas—and this movement could be in any direction. This happens in the late summer before the massive southward migration as temperatures drop across the continent.

First- and second-year geese (not old enough to breed), along with those that lost nests early in the breeding season also undertake a molt migration. Individuals may move several to hundreds of miles during the late spring and summer to large bodies of water where they will be safer as they molt their wing feathers. In September and October, many of these individuals will be returning from this seasonal journey, and again may be seen flying in almost any direction.

Also, bear in mind that there are increasingly large numbers of resident Canada Geese across North America. These birds do not migrate at all and so you may see them at any time of year flying in any direction. Their numbers have been growing exponentially since the mid-twentieth century and they have begun to be seen as nuisances in some communities. Read more on the difference between migratory and resident Canada Geese.

Q. Why do migratory birds crash into buildings at night and how can people prevent it from happening?

A. Even in the best of circumstances, spring and fall are dangerous times for migrating birds. When they migrate over major cities, the risks increase. Many potentially fatal collisions happen when a nocturnal migrant hits a lighted high-rise jutting into their airspace. Some of these collisions are random, but much more often the lighted windows lure birds to their deaths.

The reasons are not entirely understood, but nocturnal migrants often navigate by the stars and illuminated windows and other night lights often divert them from their original flight paths, especially in low-ceiling or foggy conditions. The birds mill about in the lighted area, where they collide with the lighted structure or with one another. In addition to buildings, communications towers and radio antennas pose similar threats. Hundreds or thousands of dead birds may litter city streets after a wave of migrants has passed through. In all, an estimated 100 million to 1 billion birds die each year in North America from colliding with structures.

As we learn more about where, when and how these nighttime collisions happen, we are also learning how we can prevent them. Since 1993, the Fatal Light Awareness Program (FLAP), a Toronto-based conservation society, has spearheaded “Lights Out” programs across North America, calling for buildings in major cities to turn out all of their lights each night during peak migration times. One study conducted by the Field Museum in Chicago showed that in one building, turning the lights off reduced the number of bird kills by an average of 83 percent.

There are other reasons that birds collide with buildings, and especially with windows. Visit our Window Collisions page for more on the subject, and other window treatments that help prevent collisions in residential areas.

Q. I’m getting a little tired of winter—What are some of the first spring birds to arrive, and when will they get here?

A. The answer depends a lot on where you live, of course. But several common species, such as Red-winged Blackbirds, Tree Swallows, and Killdeer, are among the first returning migrants across much of North America. You can also use data from eBird to find out when to expect birds to return to your location, and our BirdCast project for weekly forecasts during migration season predicting which species will be on the move.

Naturally, the timing of migration depends a lot on how far south or north you are—but February and early March usually bring the first returning birds. Some of the earliest spring migrants are Red-winged Blackbirds, Killdeer, American Robin (bear in mind that plenty of American Robins actually stick around all year long), Tree Swallow, and, in the East, Eastern Phoebe. Many species of blackbirds are also on the move in February, in addition to Red-winged Blackbirds, including Common Grackles and Rusty Blackbirds (in the East) and Brewer’s Blackbirds (in the West).

A great way to get a handle on when different species might be arriving in your area is by using the Bar Charts feature in eBird. By selecting your state and/or county, you can create a list of birds in your area that includes information about when they arrive and depart the region, as well as how often they are reported in any given week of the year. You can also use eBird’s new Locations feature to see the most recent reports for a given county or state.

Another way to keep up with migratory bird movement is by visiting BirdCast. The BirdCast team studies weather forecasts to make predictions about bird migration: when species will migrate, where they’ll be going, and how far they will be flying. During peak spring and fall migration times (March-May; Aug-Oct), BirdCast releases weekly migration forecasts. At other times of the year, you can find interesting analyses and discussions of weather patterns and bird movements. For example, they posted this informative blog post about some of the early spring migration patterns seen in late February 2014.

Q. How long do wintering Snowy Owls stay with us before they return to their breeding grounds?

A. Although we don't have a good handle on when Snowy Owls get back to their breeding grounds, we do know that they typically start leaving the Lower 48 in March. Scattered reports may trickle in through April and into May or even June.

One reason we know so little about Snowy Owls is that they breed in the very remote, barren reaches of the high arctic, and they visit more populated areas in winter only sporadically. During the winter of 2013-2014, scientists took advantage of the remarkable Snowy Owl irruption by embarking on Project SNOWStorm. This project aims to fill in some of the gaps in our knowledge by satellite-tracking the movements of individual owls. As part of the project, Snowies have been tagged in Massachusetts, Pennsylvania, Maryland, Delaware, New York, and Minnesota.

Norman Smith of Mass Audubon has been studying Snowy Owls in Massachusetts since 1981, and is a part of Project SNOWStorm. He says that in big irruption years like 2013-2014, when there are lots of owls around, some stay till April, and occasionally to May. It is very rare to see one in June, but the latest record for a Snowy Owl in the state of Massachusetts is July 7.

The huge amount of publicly available data in eBird is a great resource for answering this sort of question, for Snowy Owls or any other species. You can use the Explore Data section to look at data in several ways:

  • see a range map for an individual species
  • look at bar charts for a location or region, showing how the relative abundance of species changes through the year
  • choose a species and see graphs of relative abundance and other metrics over time
  • see which species have been reported for particular locations
  • narrow in on hotspots by seeing a color-coded map showing where the most species have been reported

Learn more about Snowy Owls in our species guide.

6. Birds and People

Q. In your opinion, what bird species is the most beneficial to mankind throughout planet Earth?

A. We enjoyed this thought-provoking question so much that we posed it to our entire staff in an email. The most popular answer was perhaps the most pragmatic: the Red Junglefowl (aka the chicken), chosen because of the huge number of people who benefit from their eggs and meat. Of the many other suggestions, here's a sample:

  • Birds that many people consider pest species (gulls, crows, pigeons, etc). They clean up our trash.
  • Vultures, which clean up the environment and reduce disease by dining on decaying or pest-ridden carrion.
  • Passenger Pigeons, which taught us a stark lesson about how destructive our species can be.
  • Rock Pigeons: they can provide meat, their poop can be composted as fertilizer, and they can be used for messaging—leading at least one staff member to suggest they're even more useful than earth-bound chickens. Project PigeonWatch is a citizen science project that encourages people to watch these remarkable birds.
  • Insectivorous birds (including many songbirds), because of their amazing role in controlling insect populations that otherwise consume our food, timber, and other agricultural products. Insect outbreaks can destroy hundreds of millions of hectares and incur millions of dollars in losses.
  • And last but not least, the stork. Without it, Homo sapiens would have gone extinct millennia ago!

Q. I’m getting married next month. Is it true that rice causes birds’ stomachs to explode?

A. Nope! This myth has been making the rounds on and off, sometimes based on “true” stories that even in this day and age never seem to have any video or photographic support. A great many birds, from waterfowl to Bobolinks, feed on rice in nature. It’s easily digestible. That said, the whole idea of exploding birds is alarming but somehow funny enough to have inspired a Dave Barry column in 2004, but the column itself was based on an untrue rumor.

Even if rice doesn’t harm birds, it is slippery, posing a hazard for people wearing smooth-soled dress shoes. It also may attract rodents.

Q. It sounds like there are birds stuck in my chimney. What should I do?

A. Probably the birds you hear are nesting in your chimney, and they're right where they want to be. The most likely possibility is that the birds are Chimney Swifts (assuming you live within their range in eastern North America). If so, the young will have no trouble at all leaving the chimney. It's possible they're European Starlings, which commonly nest in cavities and crevices in buildings. Those young aren't as adept as swifts, but they're still likely to be able to fly safely out of the nest when it's time.

Sometimes, larger cavity-nesting birds like Wood Ducks and Barn Owls can fall down into a chimney and are too large to fly out, but these would make quite different sounds than a nest full of chicks. If you have a traditional chimney, you can try turning off all the lights in the house, leaving a door open and opening the flue—the bird will see the light of the exit and try to get out. If that fails, it is best to contact a licensed rehabilitator; you can find one in your area here.

Make sure you don't use your fireplace until you are sure all birds have left your chimney.

Read more about the remarkable Chimney Swift (or, in the West, Vaux's Swift), listen to its chattering call, and compare it to the European Starling, in our All About Birds species guide.

Q. Should I worry that my small, five-pound dog might get attacked by a hawk or owl?

A. Although most small dogs are too heavy for a hawk or owl to actually carry, it's still possible for large raptors to attack and kill them. A five-pound dog is no bigger than a large rabbit—a hawk might easily attack and carry it away. Of course, a dog this size is also in danger from foxes, coyotes, bears, raccoons, and even other dogs, so it might be wise to let your dog out only when accompanied by you. If hawks present a significant danger because you live on a raptor migration route or have hawks nesting nearby, seriously consider getting a second dog. Hawks are far less likely to attack one dog when another, even one equally small, is nearby.

A kennel with a wire roof can also protect small dogs, not just from hawks and owls but also from other predators and human dognappers.

Q. How do I keep herons from eating the fish in my pond?

A. I can certainly understand not wanting the birds to eat expensive fish! Of course, the birds have no concept of the value of koi, and are simply doing what they do best: find and eat fish.

To get herons to pursue their livelihood elsewhere, people have tried a variety of techniques. Unfortunately, we at the Cornell Lab of Ornithology have different goals, and actively encourage herons to visit our pond here in Sapsucker Woods. For suggestions, visit the Royal Society for the Protection of Birds web page on deterring herons. The Gray Heron of Great Britain is quite similar to our Great Blue Heron, so ways of dealing with either will be quite similar. 

You can read about the Great Blue Heron and other herons and egrets in the All About Birds Online Bird Guide.

Q. There's a huge starling roost near my house and they're driving us nuts! What can we do?

A. The European Starling is an exotic species that was introduced to North America in 1890 and 1891. It's now a permanent resident across the United States and Canada, almost always near areas of human habitation, disturbance, or agriculture, so is seldom found away from cities, suburbs, parks, and farms. As you've figured out the hard way, the European Starling is considered a "problem" bird for several reasons:

  • It competes fiercely for nesting cavities, ousting such native birds as bluebirds and various woodpeckers, sometimes even killing them.
  • It is aggressive at feeders, keeping smaller birds away and consuming large quantities of seed and suet.
  • Its enormous winter foraging flocks are considered pests in agricultural areas.
  • Its huge winter roosts present hygiene challenges where humans live.
  • Roosts are very noisy.

Unfortunately, discouraging starlings from roosting around your house can be difficult at best. Installing a plastic model hawk or owl in a tree may help for a short time, but if that's all you do the birds will soon realize it poses no threat and ignore it. Many people recommend using a predator decoy in combination with another bird deterrent, such as a recording of starling distress calls broadcast through a loudspeaker, though starlings tend to habituate to these noises much more quickly than people do. A sudden loud noise may flush starling flocks from your trees, at least the first few times you try it. Some people use fireworks, or clang pots and pans together. Sometimes even just clapping your hands is enough to flush a starling flock, once or twice. But starlings are usually more persistent than people are, and least adjust to even sudden noises more quickly than we do.

Any time you notice even a single starling hanging out near your house, try to chase it away. Be persistent from the beginning to avoid having a flock become established in your yard. It's much harder to get a flock to move once they've settled in at a roost site.

One of the most effective ways of driving a starling roost away involves a particular kind of professional help. Call your local game warden or a department of environmental conservation to find out if any falconers live near you. If you can enlist the aid of falconers to come for a few visits, their birds may get a bracing hunting experience that sends the starlings packing for good.

Q. Why do woodpeckers like to hammer on houses? And what can I do about it?

A. Woodpeckers usually hammer on houses for one of four reasons:

  1. Because it makes a satisfyingly loud noise that proclaims the bird's territory and attracts a mate. If the birds are drumming for these reasons, they will most likely stop once breeding has begun in the spring (they don't drum when looking for food).
  2. Because the bird wants to excavate a nest or roost hole. If the woodpeckers are creating a nest cavity, the hole will be round and large. Nesting holes are usually built in the beginning of the breeding season between late April and May. If you need to evict woodpeckers from your home, aim to do so either before or after the nesting season.
  3. Because it is feeding on insects living in the siding. If the birds are looking for insects, the holes will be small and irregular. You may have to call an exterminator to get rid of the underlying insect problem. Woodpeckers are particularly fond of the larvae of carpenter bees, leafcutter bees, and grass bagworms. To help you identify what insects might be involved in a particular woodpecker problem, we have some photos of specific kinds of woodpecker damage.
  4. Because they are storing food. If you are located in the West, Acorn Woodpeckers peck dozens or hundreds of acorn-sized holes into large trees or houses, and stash a single fresh acorn into each one.

How can I get woodpeckers to leave my house alone? Once you know why woodpeckers are hammering on your house, you can develop strategies for stopping them. Take a look at our blog post Can Woodpecker Deterrents Safeguard My House? for ideas on how to deal with troublesome woodpeckers. The Cornell Lab's archived website Woodpeckers: Damage, Prevention, and Control also has information on woodpecker damage, clearing out problem insects to deter woodpeckers, and protecting your home.

Researchers at the Lab of Ornithology have performed studies relating nuisance woodpeckers. One study, External characteristics of houses prone to woodpecker damage, found that lighter colored aluminum and vinyl sidings are less likely to be damaged by woodpeckers. Another paper, Assessment of Management Techniques to Reduce Woodpecker Damage to Homes, tested six common long-term woodpecker deterrents: life-sized plastic owls with paper wings, reflective streamers, plastic eyes strung on fishing line, roost boxes, suet feeders, and a sound system which broadcasts woodpecker distress calls followed by the call of a hawk. Researchers found that nothing deterred woodpeckers all the time, and only the streamers worked with any consistency.

Homeowners have reported some success deterring woodpeckers with windsocks, pinwheels, helium balloons (shiny, bright Mylar balloons are especially effective), strips of aluminum foil, or reflective tape. Other people keep woodpeckers away by covering an affected area with burlap or attaching bird netting (the kind designed for gardens and fruit trees) from overhanging eaves to the siding. If you use netting, make sure it is taut and set at least 3 inches from the siding to avoid birds pecking through it. Close off openings on the sides to prevent birds from becoming trapped between the netting and the house.

You may also want to plug the holes with wood putty to discourage further activity. If a woodpecker has dug a roost hole into your house, make sure there are no birds inside before sealing it up.

Never use any sticky “repellent,” such as Tanglefoot Pest Control, Roost-No-More, or Bird Stop, outdoors. These types of products can fatally injure birds and other animals.

Q. A woodpecker is putting rows of holes in my tree. Will it hurt the tree?

A. Sapsuckers tap for running sap in the springtime, circling a trunk or large limb with their tiny drill holes, and when those wounds heal over, drills a whole new ring of holes. Surprisingly, most trees survive this quite easily, in the same way that maple trees survive humans tapping for syrup. And the sapsucker wells are vitally important for other birds, supplying a reliable source of food for hummingbirds, kinglets, Cape May Warblers, and other species, especially when they're first returning in spring. We at the Cornell Lab of Ornithology have named the beloved woods about our laboratory Sapsucker Woods, so you just know we're going to take the birds' side in this.

That said, there really are some trees that people shouldn't have to risk losing. If the woodpecker isn't working too high, the easiest, and usually most effective, way of sending a sapsucker off is to wrap the tree in burlap, over a wide enough section that it doesn't start a new ring of holes. Many birds are alarmed by bright Mylar balloons filled with helium, which wave about in a way they can't predict, so tying a few around your tree should provide additional insurance that it doesn't just start digging in a new place in the same tree. By the time the helium has dissipated, the sapsucker should be long gone.

Q. What can I do about a bird that sings all night long outside my window?

A. The Northern Mockingbird is typically the culprit in these all-night song marathons. Mockingbirds who sing all night long tend to be young, still-unattached males or older males who have lost their mate, and so the best way to shut him up is to entice a female mockingbird to your yard, too. He's already doing his best to accomplish this, though to the disappointment of both of you, he's not succeeded yet.

One thing that very well might work would be to cover your tree with bird netting—the kind sold in gardening stores to keep birds out of fruit trees. You'll need to check on it occasionally, since sometimes tiny birds get entangled in it, but you can do that in the daytime after a good night's sleep. And maybe by sending your bird elsewhere, you can sleep and he can be more effective in attracting a mate. Good luck, and please let me know what happens.

I don't know if it will help to know that the mockingbird was Thomas Jefferson's favorite bird. He wrote a lot about its amazing mimicry abilities and songs, and how England had nothing to compare with it, in his Notes on the State of Virginia. He also had a pet mockingbird named Dick who lived in the White House.

Robert Frost's poem, "A Minor Bird," will be less than consoling, seeming rather judgmental for someone who just wants a decent night's sleep:

   I have wished a bird would fly away,
   And not sing by my house all day;

   Have clapped my hands at him from the door
   When it seemed as if I could bear no more.

   The fault must partly have been in me.
   The bird was not to blame for his key.

   And of course there must be something wrong
   In wanting to silence any song.

Because of course there must be something right about wanting a decent sleep at night.

Q. I found a pigeon or dove that seems tame and has colored bands on its legs. What should I do?

A. This sounds like a domestic racing or homing pigeon. Sometimes these birds become exhausted and need just a few hours or days to rest or feed before they head home again. Sometimes they are injured or lost. In some cases, owners who want to maintain a competitive racing flock don't want their birds back again, but more often tracking down the owners can be a genuine kindness.

When scientists put bands on wild birds, they use metal bands issued by the U.S. Fish and Wildlife Service. Racing and other domestic pigeons never wear these bands; their owners use different bands usually registered with either the American Racing Pigeon Union or the International Federation of American Pigeon Fanciers. If you can read the leg band numbers, you can contact these organizations to try to track down the pigeon owners.

Did you know that some of Charles Darwin's revelations about evolution came from the many years he spent raising pigeons? Read about it in Living Bird magazine.

Q. How can I share my bird photos with the Lab?

A. We're constantly thankful that people share so many wonderful images with us. If you've taken some photos and want other bird enthusiasts to see them, there are several ways to share them with us:

  • Birdshare: This is the Cornell Lab’s primary photo-sharing group—as of Dec. 2013, there are over 4,000 members and over 180,000 photos to explore. It's hosted on Flickr—you just need to have a Flickr account, join the Birdshare group and start adding your photos. In joining, Birdshare users agree to let us use their photos on the Cornell Lab’s website. This photo group is a major source of photos for our free online species guide, and that guide couldn't exist without the generosity of Birdshare members.
  • The Cornell Lab Facebook page: Join us on Facebook and upload your photos to our wall. Your photo will appear in the "posts by others" section where people comment and help with ID questions. Each week we draw photos from this pool to highlight in Community Photos collections.
  • Project-related contests and challenges: Project FeederWatch often runs their BirdSpotter photo contest during the winter, with the help of sponsor Bob's Red Mill Natural Foods. Also check in with Celebrate Urban Birds, which runs a variety of photo challenges through the year. Both often feature prizes!
  • If you use eBird, you can add photos to your checklists to verify notable birds or just to show off a picture or bird you're particularly proud of. These photos are then viewable by other eBird users through our rich media search function.

What if you've got a question about a photo but you don't really want to share it? You can always send pictures for ID and other questions to cornellbirds@cornell.edu. We'll do our best to answer—and we won’t share them without your permission.

Q. How can I keep birds from hitting my windows?

A. After cats, windows are one of the deadliest threats to birds in America. Researchers estimate that between 100 million and 1 billion birds are killed by colliding with glass every year, in the United States alone.

If you're selecting new windows while building or remodeling, if at all possible choose double-hung windows or other types with the window screens on the outside. If you're putting up a large picture window and like the effect of small panes, putting dividers on the outside as well as the inside will also help.

But most of us are stuck with the windows we already have, or are limited in our options in selecting new windows. Sticking one or two decals on a window will not help. You might try one of these techniques, ranked roughly from most to least effective:

  • Cover the glass on the outside with window screening or netting at least 2–3 inches from the glass, taut enough to bounce birds off before they can hit the glass. The is the kind of netting that is effective for protecting birds from hitting windows is sold in garden stores to protect trees and shrubs. This netting should be drawn taut across the windows, 2-3 inches from the glass, or birds could get entangled. It shouldn't hurt your view at all on vaulted windows set high up anyway, nor will it reduce the solar benefits at all significantly. But it will both make the windows a little more visible and act like a trampoline so when birds do hit, they'll bounce off.
  • Cover the outside surface of the glass with a one-way transparent film that permits people indoors to see out, but makes the window appear opaque on the outside.
  • Place vertical strips of tape on the exterior glass, set no more than 4 inches apart, or cover the exterior glass with decals placed close together (no more than 4 inches apart).
  • Mark the glass with permanent paint or markers. Birds can see in the ultraviolet spectrum, but painting windows with ultraviolet markers usually helps for only a few days because most of these inks fade very quickly.
  • Install external shutters and keep them closed when you're not actively enjoying the light or view.
  • If you have interior vertical blinds, keep the slats half open.
  • Window decals can work, but you must put up many, set only a few inches apart, on each glass panel. Sadly, birds do not respond to falcon and owl silhouette decals the way people once believed. Visit our Window Collisions page for more suggestions and photos of window treatments that help prevent collisions.

Check out our Winter 2014 Living Bird article, Glass Action for Birds, for more information and visit our Window Collisions page for suggestions and photos of window treatments that help prevent collisions. You may also want to check out our blog for a brief report on the problem of bird strikes as discussed at the 2009 meeting of the American Ornithologists' Union. For more information on solutions, one of the field's leading researchers, Dr. Daniel Klem, has posted several research papers with promising solutions on his website.

7. Bird Sounds

Q. Why do some birds mimic the sounds of other species?

A. Although some birds learn their species' song during their first year of life, others, including mockingbirds, continue adding to their repertoire as they grow older. Northern Mockingbirds can learn as many as 200 songs, and often mimic sounds in their environment including other birds, car alarms, and creaky gates. One theory is that if a female prefers males who sing more songs, a male can top his rivals by quickly adding to his repertoire some of the sounds around him. Possessing a diverse assortment of songs may indicate he is an older male with proven longevity and survival skills--good traits to pass on to offspring. An older male may also be more experienced in raising young or may have access to better resources. According to one study on the Edwards Plateau in Texas, mockingbirds with the largest repertoires have the best territories, laden with foods such as insects, wild grapes, and persimmons.

Some researchers have suggested that mockingbirds may use other species' songs to warn those species to keep away from their territories, but this possibility has never been thoroughly investigated.

In North America, the Northern Mockingbird is perhaps the best known mimic, but renowned mimics, such as the lyrebirds of Australia and the Lawrence's Thrush of South America, occur on other continents too. Male Marsh Warblers learn the sounds of other species on their wintering grounds in Africa. Perhaps these varied sounds impress potential mates when they return to breed in Europe. Indigobirds in Africa are also mimics, but for an entirely different reason. Indigobirds are brood parasites that lay their eggs in the nests of other species. For example, the Village Indigobird lays its eggs in the nest of the Red-billed Firefinch. Young indigobirds learn the begging calls of the firefinches that raise them so they will not be recognized as an intruder. Young male indigobirds also mimic their hosts.

The female Thick-billed Euphonia is a Neotropical bird that imitates the alarm calls of other species when her nest is threatened. These sounds may get the attention of other species to help in the attack of a predator or other perceived threat.

Some species not typically thought of as mimics also occasionally learn the vocalizations of other species. Blue Jays imitate the calls of Red-tailed, Red-shouldered, and Broad-winged hawks, for example. The function of these imitations is unknown.

In some cases, mimicry may result from the song-learning process gone awry, such as reports of a Vesper Sparrow and House Wrens singing songs of the Bewick's Wren, and an Indigo Bunting and a Common Yellowthroat singing a Chestnut-sided Warbler song. It seems that a fairly large number of these occasional mimics are unpaired, suggesting that males who learn the wrong songs often fail to pass their genes to the next generation. Selection against birds who learn the wrong songs may thus be very strong, so "mistakes" are not perpetuated. (Source: The Cornell Lab of Ornithology's Handbook of Bird Biology)

Q. Which birds are the best mimics?

A. Several birds could make the claim to be the world's best mimic. In North America master mimics include mockingbirds, thrashers, and catbirds; all of which are in the family Mimidae, so named because of this family's skill at mimicking other species. The Brown Thrasher can sing up to 2,000 different songs and may be the champion mimic in North America. European Starlings are also accomplished mimics, just like their relatives the mynas, and are known to include imitations of other birds, but also just about anything else, including motorcycles and tea kettles. Blue Jays can mimic several species of hawks.

Parrots are especially adept at mimicking sounds and human language. Unlike songbirds, which produce sounds by vibrating membranes in two different syrinxes, parrots have only one syrinx, located at the bottom of the windpipe. This is somewhat similar to humans, who also have only one sound-producing organ, the larynx. Parrots also have long, muscular tongues that may be used in modifying sounds. Parrots also have forebrain areas involved in vocal learning and control of vocalization that are not found in other birds.

African Gray Parrots are one of the most accomplished mimics. A bird named "Prudle", a male African gray, is listed in the Guinness Book of World Records as having a vocabulary of more than 1,000 words. The Animal Planet network featured an African Gray Parrot that lives up to his name—Einstein.

In this video, listen to our audio curator, Greg Budney, point out the many birds (and even a frog) mimicked by one very accomplished Gray Catbird.

Q. Do parent and baby birds recognize each other's songs or calls?

A. Adult birds may or may not recognize their young, depending on the species and nesting habits.

The Brown-headed Cowbird lays its eggs in the nests of other species. The host species does not seem to notice the difference between the calls of their own babies and that of the cowbird.

Adults of species such as Barn Swallows never learn to recognize the calls of their own young. This pattern may have developed because the young birds become independent immediately after fledging or because they remain isolated in their family group until they are fully independent.

In colonial species the situation is very different. Within a few days of hatching, adults learn to recognize the voices of their own chicks, and vice versa. Herring Gulls, for example, may accept tiny young into their nest for a short period after their own eggs have hatched. After two to three days, however, they will not allow strange young into their nesting area.

Q. Do bird songs have frequencies higher than humans can hear?

A. The frequency range of human hearing is often reported to be between 20 and 20,000 Hz. As we grow older, we all tend to lose the ability to hear higher frequencies.

Many bird songs have frequency ranges between 1,000 Hz and 8,000 Hz, which places them in the sweet spot of human hearing. On the high end, many warblers, sparrows, waxwings, kinglets, and a number of other birds produce sounds that reach 8,000 Hz and beyond. Examples of the frequency ranges of bird songs:

  • Brown Creeper: from 3750 to 8000 Hz 
  • Cedar Waxwing: from 6000 to 8000 Hz
  • Blackpoll Warbler: from 8000 to 1020 Hz
  • On the low end, Dwarf Cassowaries in New Guinea have been recorded giving calls as low as 23 Hz.

You can test your own hearing by visiting a web page from the University of Kentucky, "Frequency Response of the Ear." You will have a choice of frequency ranges. Keep in mind that the frequency response of the speakers attached to your computer, especially internal speakers, will have a limited frequency response range. This will often fall between about 100 and 10,000 Hz. Check the specifications on your speakers to determine their frequency range.

Q. What is the most beautiful bird song in North America?

A. Some people believe the thrushes, such as the Wood Thrush,  or the Veery, have the most beautiful bird songs. Many people love the cry of the Common Loon. Click on the links and listen to their songs. See if you don't agree. If you don't, what is your favorite song? Why is it your favorite? Let us know and we'll post some of the answers.

Q. Why are Blue Jays far more noisy in fall than earlier in the summer?

A. Early in the summer they're nesting, and being as secretive as possible. Now families have joined flocks and are migrating to new areas. It's right in the middle of hawk migration, too, so they're all squawking their heads off about new food discoveries, predators, greeting relatives and old neighbors, and they're no longer concerned about predators finding their nests.

Find more photos, sounds, video, and text on our Blue Jay page.

Q. How does a tiny bird like a Winter Wren manage to sing so many sounds so quickly, and so loudly?

A. As with other splendid bird songs, our experience of Winter Wrens transcends a mechanical understanding of sound production. In 1884, the Reverend J. H. Langille described his experience listening to the Winter Wren: “I stand entranced and amazed, my very soul vibrating to this gushing melody, which seems at once expressive of the wildest joy and the tenderest sadness.”

Per unit weight, Winter Wrens have 10 times the sound power of a crowing rooster, and birds in the eastern population sing a good 16 notes per second—an impressive output that is not only exceeded but more than doubled by western birds, which sing 36 notes per second! Their rapid heartbeat, respiratory rate, and metabolic rate don’t explain the output, since larger and smaller birds don’t match this! But what is even more amazing is that these birds not only produce the sounds but react to tiny parts of the songs, so their ears and brain can resolve in real time individual notes that we cannot without replaying the songs at slow speed.

Hear the Winter Wren's vocal acrobatics in our All About Birds guide.

Q. I've been hearing beautiful bird songs every morning since spring, but suddenly I'm not hearing birds at all! What happened to them?

A. Birds sing for two basic reasons associated with nesting: to attract a mate and to defend a territory. By July, many baby birds have fledged, and adult birds are busy feeding them and teaching them how to find their own food and other survival skills. At this point, species that raise only one family a year may stop singing altogether, but some have a brief resumption of song, which may help teach the young of those species their local song dialect. But overall, one by one, each species drops out of the spring chorus until by late July, only a handful of birds are still singing at all. One of our most noticeable backyard songsters, the American Robin, may renest several times from its arrival in early spring through summer, but even robins don't start new nests after late July or at the latest early August. At this point, they stop feeling territorial and join sociable feeding flocks, and territorial singing is just not compatible with flocking.

Those of us who treasure the spring dawn chorus usually feel a sense of loss at the sudden silence. Robert Frost's poem, "The Oven Bird," is about this forlornness. Frost notices that the Ovenbird sings later in summer than most birds, and concludes his poem, "The question that he frames in all but words/ Is what to make of a diminished thing."

Ironically, this silence and secretive behavior as birds raise their fledglings and then molt makes them least conspicuous right at the time of year when birds are most abundant, when populations of adults are augmented by all the young birds they produced this year. By spring, bird numbers are greatly reduced after losses during two migrations and over winter, but that's when they're most conspicuous thanks to that rich singing.

8. Science and Conservation

Q. Do all birds have gizzards?

A. What we call a gizzard is the muscular part of a bird's stomach. When a bird swallows food, it goes from the throat to the esophagus. Some species have an expanded, thin-walled offshoot or pouch in the esophagus called the crop where they can store food before it’s sent the rest of the way through the esophagus to the stomach. (Pigeons and dove adults produce a food for their young called crop milk in the crop.)

Birds all have two parts to their stomach. The first is called the proventriculus or glandular stomach, where digestive enzymes are secreted to begin the process of digestion. This part of the stomach is very much like our stomach.

The second part of a bird’s stomach (a part we humans don’t have) is the gizzard or muscular stomach. The gizzard is very thick and muscular in some species, such as ducks, gallinaceous birds (those related to chickens such as grouse, quail, and turkeys), emus, and doves. Most of these birds eat hard items such as seeds and nuts. Birds with thick gizzards frequently pick up grit—little stones, sand, and small shells. These items collect in the gizzard. When food and digestive juices enter the gizzard, the thick muscles and grit help pulverize the food. When you buy chickens or turkeys at the grocery store, they often have a little bag of “giblets” that includes the very thick, muscular gizzard. (The other organs that are considered part of the giblets are the liver and heart.)

Owls swallow most small prey whole. In both chambers of the stomach, soft tissue from the prey is liquefied and then moves on to the intestines. Bones, teeth, feathers, and fur collect in the gizzard. After all the digestible material has emptied into the intestines, the gizzard muscles contract to squeeze most of the remaining liquid into the intestines, and then the bird coughs up the non-digestible material as a “pellet.”

All birds do have a gizzard, but those species that eat very easily digested foods such as soft-bodied insects, soft fruits, or nectar may have a very small and thin-walled gizzard.

Q. Why can't penguins fly?

A. Well, in a sense they really do fly, only through the water, not through the air. Penguins have strong wings and strong pectoral muscles to power them. Their bodies are streamlined as if for flight, so they still cut cleanly through the water. But water is much thicker than air, so their wings are shorter and stiffer than a normal bird's wings. In fact, penguins are the only birds that are unable to fold their wings. Their wing bones are fused straight, making the wing rigid and powerful, like a flipper.

By the same token, penguins aren't nearly as concerned about being light as birds that fly through the air. To dive deep, to catch fast-swimming prey, and to survive frigid temperatures, their bodies have huge fat supplies, heavy muscles, and densely packed feathers. There's no way they could fly with such short wings and heavy bodies.

Penguins are an interesting example of specialization versus compromise. By giving up on flight they've been free to evolve bodies that perform superbly underwater. The similar-looking murres and guillemots of the Arctic can still fly, just not as well as some other birds; and they can also swim, though not as well as penguins.

Q. Do vultures find dead animals by smell or by tracking predators or scavengers on the ground?

A. Researchers proved fairly long ago that Turkey Vultures can smell. In 1938, the Union Oil Company discovered that by injecting a strong-smelling organic chemical called mercaptan into gas lines, they could readily find leaks by monitoring vulture activity above the pipelines. Some mercaptans smell like rotting cabbage or eggs. They and related chemicals are released as carcasses decompose. To us, mercaptans smell horrible, but for vultures they are associated with fine dining.

In a 1986 study in Panama, Turkey Vultures found 71 of 74 chicken carcasses within three days. There was no time difference between finding concealed and unconcealed carcasses, and the only carcasses the vultures seemingly had trouble finding were the freshest ones. Even though the older carcasses emitted a stronger odor, the vultures showed a definite preference for eating fresher carcasses.

Greater and Lesser Yellow-headed Vultures of Central and South America, which are closely related to Turkey Vultures, seem to have comparable reliance on their sense of smell for finding food, and King Vultures may also use smell to find food. These species must all be able to find carrion in forests where the canopy visually obscures dead animals. Unlike these species, Black Vultures, which find their food primarily in open country, depend far more on vision and are believed to have a relatively poor sense of smell. Of course, one strategy that all vultures use to locate food is to watch for other circling vultures to drop down suddenly; in that sense, even Turkey Vultures find much of their food visually.

Q. On a visit to Ithaca, New York, I saw a crow with large, red tags on each shoulder. Is this one of your projects?

A. Yes—those are what we call "Kevin's crows."Lab scientist Dr. Kevin McGowan has been following individual crows in our area for decades. His research has taught us many things about these common and widespread birds, including giving us insight into the epidemic of West Nile Virus and learning about ways crows cooperate. Kevin works in our education department, and he maintains his own site all about his crow project.

Q. I believe that the same blue heron has been perching on my dock for 28 years. What is their life span?

A. The oldest Great Blue Herons we know of in the wild lived to be 23 and 24 years old. Yours may be the same bird, but remember that Great Blue Herons like to fish alone. Birds flying over that see one having luck on your dock may come down there occasionally when that one flies off, so you may actually be seeing more than one individual.

Or it may really be the same bird—the only way scientists can be certain is to mark the bird with a U.S. Fish and Wildlife Service numbered band and, sometimes, a colored leg or neck band, or wing tag, and check the color/number every time the bird is observed. Whether it's one bird or more, it's very exciting that you have such a reliable visitor!

Check out our All About Birds species guide for detailed information on North American Birds including information on longevity. You can also browse through The USGS Patuxent Wildlife Research Center's Longevity Records of North American Birds.

Q. How much do birds eat each day?

A. This completely varies depending on what species you're talking about. As with mammals, the amount of food a bird eats depends on the caloric value of the food, the size of the bird (the smaller the bird, the more it needs relative to its body weight), the bird's activity levels, and the temperature of its environment.

A chickadee may eat 35 percent of its weight in food each day while a Blue Jay may eat only 10 percent of its weight and a Common Raven only 4 percent—but they all need more calories on colder days than warmer ones. Hummingbirds can consume 100 percent of their body's weight in sugar water or nectar every day, in addition to as many as 2,000 tiny insects! Before migration, it's not unusual for a hummingbird to double its weight, adding a huge amount of fat to power the long journey.

Canada Geese eat lots of grass each day, partly because grass doesn't have a lot of usable calories per pound. A 5-pound Canada Goose eats about a half-pound of grass per day (about 10 percent of its body weight).

Q. How can Bald Eagles survive in northern areas after all the lakes have frozen?

A. As much as eagles enjoy fresh fish, they will also dine on carrion and garbage. It may be disconcerting to see the emblem of the United States of America eating at a dump or at a carcass on the side of the road, but the ability of eagles to exploit a wide range of food choices is one of the keys to their success.

Read more about the Bald Eagle in our free bird guide, or see these remarkable photo portraits from our August 2009 featured photographer, Tony Markle.

Q. Why don't birds get cold feet?

A. Actually, songbirds do get very cold feet: the surface temperature of their toes may be barely above freezing even as the bird maintains its core body temperature above 100°F (38°C). But most birds don’t succumb to frostbite because there is so little fluid in the cells of their feet, and because their circulation is so fast that blood doesn’t remain in the feet long enough to freeze.

We don’t know if cold feet bother birds like Common Eiders or Snow Buntings. We do know that they have few pain receptors in their feet, and the circulation in their legs and feet is a double shunt— the blood vessels going to and from the feet are very close together, so blood flowing back to the body is warmed by blood flowing to the feet. The newly cooled blood in the feet lowers heat loss from the feet, and the warmed blood flowing back into the body prevents the bird from becoming chilled.

Q. Do birds have teeth?

A. Birds do not have teeth. Birds swallow their food whole, and their gizzard (a muscular part of their stomach) grinds up the food so they can digest it. Gizzards can be amazingly powerful—some birds such as scaup and eiders swallow clams and mussels whole, letting their gizzards pulverize the shells.

Q. Why are loons chasing each other across my lake?

A. Your encounter sounds like a territorial flight—a dispute between two loons. Late June is well past the point when loons are first establishing territories, but it's possible one loon had been displaced from its own lake or had not managed to find a territory yet and so was intruding on another bird's territory. Loons can battle for a long time, and sometimes one is actually killed. It must have been both thrilling and disconcerting to witness this.

Read more about Common Loons in our online species guide, and listen to their ethereal calls in this audio slideshow.

Q. Do hawks flock together?

A. Hawks do sometimes form large flocks. They're usually taking advantage of rising thermal air currents, and you may see dozens (and, during migration, up to thousands) soaring together in the right conditions. These swirling, circling flocks are called "kettles." By watching for these gatherings, the hawks can more easily find thermals, minimizing their need to flap on their long journeys.

But what you're describing sounds like it might be Turkey Vultures rather than hawks. These birds very often fly in gatherings of the size you describe, sniffing out the dead animals they feast on.

Compare Turkey Vultures against common North American hawks such as the Red-tailed Hawk, in our online species guide.

Q. How are coffee and birds related?

A. Coffee farms can provide good habitat for birds—including for wintering migrants from North America as well as birds that live year-round in the tropics. Or it can provide poor habitat—it’s largely a matter of how the coffee is grown. Many of the colorful songbirds that we enjoy in the United States—including warblers, tanagers, orioles, and grosbeaks—migrate south to the tropics and winter in Mexico and Central and South America for five months. Some of the world’s top coffee-producing countries are located there, so coffee farms are a major land use in an important region for wintering bird habitat. By buying sustainable (and particularly "Bird Friendly" labeled) coffees, you can help provide economic support for important bird habitat.

Keep reading our shade coffee FAQ (below), or visit our main page about Bird Friendly, organic, and shade-grown coffees.

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Q. How can coffee help or harm birds?

A. Coffee can be grown under the shade of a canopy, or it can be grown out in the open sun. So-called “sun coffee” is resource-intensive and offers far less habitat for birds. “Shade-grown coffee” tends to support more bird species and require fewer pesticides and fertilizers—although different kinds of shade coffee can be better or worse for birds and the environment. Here’s the background:

The Dutch introduced coffee to the New World in the 1700s as a forest-floor crop grown under a dense overhead forest canopy. Today some coffee farms still use this traditional, rustic method of growing coffee. Artificial fertilizers aren’t as necessary, because decaying leaf litter recycles nutrients to feed the coffee plants. Pesticides aren’t needed, because more birds are around to eat insect pests. Many tasters find this rustic coffee yields a higher quality brew that tastes richer. This is partly because forest coffee isn’t machine harvested but picked by hand, allowing people to choose only the ripe coffee berries.

But modernization in coffee growing has introduced sun-tolerant varieties of coffee that can be grown in the open and tend to have higher yields than shade-grown coffee. The technique is much harder on the environment, however. Forest must be cut down; pesticides and fertilizers are employed to stimulate yields, and higher profits. In some places, sun-grown coffee has come to dominate the landscape. For example, in Colombia, about 70 percent of coffee croplands have been converted to sun-grown operations.

Shade-coffee farms beneath forest canopy provide critical strongholds of quality habitat for Neotropical migrants, according to Bridget Stutchbury of Toronto’s York University. At least 42 species of North American migrant songbirds spend winters in coffee plantations, and 22 of those species have declining population trends, Stutchbury said. This makes traditional coffee farms an important resource. Conversion of tropical forest to sun-grown operations is happening right now, when songbirds can least afford to cede more ground.

Keep reading our shade coffee FAQ (below), or visit our main page about Bird Friendly, organic, and shade-grown coffees.

Q. Is drinking shade-grown coffee good for birds?

A. “Shade-grown” labels often appear on coffee, but these words are not regulated and they don’t tell you much about the actual growing conditions at the farm. Unfortunately, unless it is accompanied by a third-party certification stamp such as the Smithsonian’s “Bird Friendly” on the package, “shade-grown” is often just a marketing buzzword. Some farms grow shade coffee among sparse, heavily pruned trees or under banana crops. These farms often lack diverse forest structure, offer little habitat for songbirds, and require fertilizers and pesticides to keep the coffee growing.

Keep reading our shade coffee FAQ (below), or visit our main page about Bird Friendly, organic, and shade-grown coffees.

Q. What's the difference between shade-grown, organic, fair-trade, and Bird-Friendly coffee?

A. The organic and fair-trade certifications are laudable programs that give you some confidence about the environmental and social conditions at the coffee farm. However, they don’t expressly safeguard habitat, particularly shade coffee, for migrant songbirds. The Cornell Lab views them as a good intermediate level of sustainable coffee, but there are better options.

Bird Friendly coffee is certified according to standards set by scientists at the Smithsonian Migratory Bird Center. To earn the certification, farms must meet rigorous standards for dense forest shade cover, multiple layers of forest structure, and the presence of epiphytes, which are indicators of forest plant and insect diversity.

The Bird Friendly stamp is a triple certification, because it also meets organic and fair-trade requirements. The Cornell Lab views Bird Friendly as the gold standard of coffee certifications, and we encourage all coffee-drinking bird watchers to use Bird Friendly coffee.

Learn more about Bird Friendly coffee and find out where to buy it in stores or online at our main page about Bird Friendly, organic, and shade-grown coffees.

Q. Why do female Belted Kingfishers have an extra rust-colored “belt” that the males don’t have?

Male and a female Belted Kingfisher

Male (left) and female (right) Belted Kingfishers by Brian E Kushner.

A. When a species is sexually dimorphic—meaning the males and females look different—the overwhelming pattern is for males to be more colorful than females. But in a few species this setup is reversed. Often, this comes along with a reversal in sex roles—one example is in shorebirds called phalaropes, where the females are more colorful and the males tend the nests. However, in the Belted Kingfisher the female has an “extra” belt but there’s no such reversal in roles. What’s going on?

There are a couple of possibilities, although the final answer has yet to be found. One suggestion comes from the idea that most features of a species arise because they confer some kind of advantage (scientists call this an “adaptationist” view.) A study in the 1970s suggested that the plumage difference helps male kingfishers recognize females, and that it arises from a quirk in kingfisher migration.

Belted Kingfishers are highly territorial, and males sometimes remain on their territories year-round, presumably so they don’t risk giving up prime nesting real estate. The females, on the other hand, migrate south for the winter. When the females return, the males are already in the midst of defending their territories. So glimpsing a flash of a bright, rusty belt could be a signal that he should welcome the visitor, rather than chasing her off.

While this is a compelling idea, some scientists argue that not all explanations have to be adaptationist in nature. Some features come about as a result of the development of other features, rather than for any specific reason of their own. For example, female kingfishers tend to be more aggressive and territorial than males during the breeding season. This may mean that female kingfishers have higher-than-normal testosterone levels—and high testosterone levels may also affect the way pigments are incorporated into a bird’s plumage. The necessary studies to distinguish between these two possibilities—or to test still other hypotheses—have yet to be done. It’s a good example of how scientific questions are all around us, waiting for curious people to investigate.

For more about Belted Kingfishers, visit our All About Birds species guide.

Q. Why don’t birds collide when they are flying close together in tight flocks?

A. The simple answer to this deceptively complex question is that birds in a flock pay close attention to the birds around them—particularly their closest neighbors.

We often marvel at the amazing collective movements of groups of birds, from groups of sandpipers wheeling in a hairpin turn along a beach, to skeins of Snow Geese flying over the prairie. One common example is flocks of European Starlings. They create immense, swirling figures across the sky (often called "murmurations," though this term technically applies to any group of starlings) that are hard to miss.

Surprising as it may be, flocks of birds are rarely led by a single individual. Even in the case of geese, which appear to have a leader, the movement of the flock is actually governed collectively. But starling flocks in particular display remarkable density of individuals, fluidity of motion, and frequent changes in direction. (Incidentally, these flocks often form because a Peregrine Falcon or other raptor is nearby. Read A Darwinian Dance in Living Bird magazine for more.)

The motion of starling flocks is so fascinating that it has inspired study among computational physicists who try to understand how such coordination can spontaneously arise. One group of researchers determined that when one starling changes direction or speed, each member of the flock responds almost instantaneously, regardless of the size of the flock—a phenomenon they termed "scale-free correlation." Another group determined that starlings in large flocks consistently coordinate their movements with their seven nearest neighbors.

For more about these studies—and to watch a video of a "murmuration" in action—see our article: How Do Starlings Flocks Create Those Mesmerizing Murmurations?

Q. How can an owl catch a mouse underneath a foot of snow in total darkness?

A. Owls do have excellent vision, but one would need either infrared or x-ray vision to see a small mammal under snow. Instead, owls do much of their hunting with the aid of their incredible hearing.

Owl hearing has been most extensively studied in Barn Owls. These pale predators can see very well in low light, but their ears are better. Their hearing is the best of any animal that has ever been tested.

All owls possess extremely sensitive hearing, allowing them to hear low-volume sounds that are relatively far away. But beyond that, many owls also have an uncanny ability to hone in on the exact location of a sound source. Owls with this special ability have an unusual anatomical trait: ears that are positioned asymmetrically on their heads.

In the Barn Owl for example, the external ear canals are offset in two ways. One ear is higher than the other, and one ear is also farther forward on the head than the other. This unusual arrangement helps the Barn Owl locate the source of sounds in three-dimensional space with great precision. Tiny differences in the time it takes for sounds to reach each ear allow the owl to almost instantly zero in on the sound's precise location. The owl can determine not only the direction of a sound, but its height (i.e. on the ground or in a tree) and distance as well.

For more on the amazing life of the Barn Owl, including other cool facts and recordings of its calls, see the species account at All About Birds.

Q. Are Whip-poor-will populations declining? What can we do about it?

A. Whip-poor-wills are doing poorly throughout most of their range. Partners in Flight lists them as a “Common Bird in Steep Decline”, and the North American Breeding Bird Survey estimates a 69% drop in populations between 1966 and 2010. There is no surplus population anywhere from which to take individuals to reintroduce, and they, like most nightjars, are exceptionally difficult to maintain in captivity, so it would be hard to raise individuals for a reintroduction project.

Many people miss the nighttime sound of Whip-poor-wills, but until scientists work out exactly why they are declining, it's difficult to determine how to restore their populations. You can help in this effort by joining the United States Nightjar Survey Network, a citizen-science project based at the College of William & Mary.

Q. What is the Migratory Bird Treaty Act?

A. The Migratory Bird Treaty Act was signed by the United States and Canada in 1918 for the purpose of ending the commercial trade in feathers. Around the turn of the 20th century, the long breeding plumes on many bird species were highly prized fashion accessories, and thousands of birds were indiscriminately killed for this purpose. This led to the formation of many conservation organizations, including the Massachusetts and National Audubon Societies, which in turn helped lobby for the passage of the act.

The act was an early landmark in conservation, at a time when birds were under intense hunting pressure and many of the public still regarded nature as inexhaustible. For example, in 1857 an Ohio Senate committee denied a measure to protect the Passenger Pigeon, writing:

The passenger pigeon needs no protection. Wonderfully prolific, having the vast forests of the North as its breeding grounds, traveling hundreds of miles in search of food, it is here today and elsewhere tomorrow, and no ordinary destruction can lessen them, or be missed from the myriads that are yearly produced. (source: sialis.org)

As many people know, the last representative of the species—named Martha—died in captivity in the Cincinnati Zoo on September 1, 1914. The species' sudden extinction provided impetus to the growing conservation movement.

The treaty prohibited the hunting, killing, capturing, possession (this is why we don’t keep or raise baby birds or try to nurse injured birds back to health ourselves!), sale, transportation and exportation of migratory birds, and their feathers, eggs and nests. It also provided for the establishment of refuges to protect bird habitat, and it encouraged the monitoring of bird populations for conservation purposes. Amendments to the initial treaty extended its range to include other nations: Mexico in 1936, Japan in 1972 and the USSR (now Russia) in 1976 are all included in the act today.

Not all North American bird species are protected under the act. Birds that are considered non-native species such as the House Sparrow and the European Starling are not protected, and many groups of hunted or game birds, including ducks, geese, doves, and many shorebirds are subject to limited protection and can be hunted in season.

Although many of the birds that are protected by the treaty are not long-range migrants, it can be argued that even “year-round” birds move around in search of local food sources, and are thus afforded protection under the act.

Over 1,000 bird species are currently protected.

For more information, read the Fish and Wildlife Service's page on the act.

9. Bird Breeding and Nests

Q. There's a bird nesting near my house. What should I do?

A. In general, the best thing you can do for a bird nesting near a human dwelling is to try to minimize the disturbance—stay at a respectful distance, minimize foot traffic, door openings/closings, and postpone and projects or construction slated for the area.

If a bird is nesting in an inconvenient place on your property, the good news is that the nesting period is not forever, and in some species may only be matter of weeks. The nesting cycle for most songbirds, robins included, is around 4 weeks from egg laying to chicks leaving the nest (two weeks of incubation, two weeks of nestlings). Try not to use the area around the nest until the young have fledged to ensure that the parents will not abandon their nest. If this is not possible, try to minimize your presence around the nest; many yard birds are tolerant of occasional disturbances.

We don't recommend that you move the nest; Birds will often abandon their nest if it is moved. Only in extreme circumstances should you consider relocating a nest, and if you do, it must be replaced very close, within a few feet of the original location. Once relocated, watch and make sure the parents are returning. If the parents do not return, contact a wildlife rehabilitator.

Some people choose to put up feeders or leave mealworms around to try to provide an additional food source for birds nesting nearby, but this is not necessary for the nest to be successful.

If you are enjoying observing a nearby nest, and would like to go a step further and collect data for science about the nesting behavior, please consider joining NestWatch. All About Birds is an excellent resource for finding out information about birds in general and about incubation and fledging times for individual species.

Q. I found a songbird nest with two different types of eggs in it. What is going on?

A. If you are in the U.S. or Canada, there is a good chance you've discovered a nest with Brown-headed Cowbird eggs in it. Cowbirds don't build their own nest; instead they lay their eggs in other birds' nests and their chicks are raised by the host species—a behavior known as brood parasitism. This can be detrimental to the host bird, but like other native birds, cowbirds and their eggs are protected by the Migratory Bird Treaty Act and it is illegal to disturb them. Read more about this interesting species in our online bird guide.

Q. How can I protect the baby birds in a nest from predatory birds and other predators like snakes and cats?

A. Nests of all kinds can be vulnerable to attacks from predators, such as Blue Jays, crows, grackles, and many other species of birds, mammals, and reptiles. If the nest is located in a natural position, such as in a tree, there is usually very little that can be done to protect the nest. In some situations baffles can be placed around trees to prevent climbing predators from reaching the nest. You can also discourage predators from hanging around the area by not leaving food outside. Keeping pets indoors, especially during the nesting season, can also save millions of birds every year.

If the nest is in a nest box or birdhouse, then you have a better chance of protecting the nest and its occupants. Our NestWatch project has everything you need know about birdhouses—from  placing them in a good location, installing a nest box camera, finding the right house for each species, and protecting the nest box from predators. Nestwatch can also help you figure out how to deal with invasive species such as European Starlings and House Sparrows. Check out Nestwatch's Trouble Shooting guide for other nest box concerns.

Q. I found a nest near my house and want to observe it but I am worried about disturbing it. Can you give me any advice?

A. Observing nesting birds deepens our understanding and appreciation of the complex and fascinating lives of these animals. But nest monitoring needs to be done safely for it to have value for both the birds and for you. The Cornell Lab runs a citizen science project called NestWatch that offers the following advice about how to monitor a nest safely:

  • Do not check in the early morning. Most birds lay their eggs in the morning so plan on visiting nests in the afternoon. Also, most adults will temporarily leave the nest when you are near, and eggs and young nestlings can become cold quickly if left alone in the morning.
  • Avoid disturbing nests during the first few days of incubation. If necessary, observe nests from a distance and approach only when the female leaves the nest.
  • Do not approach nests when young are close to fledging. When the young are disturbed during this stage, they may leave the nest prematurely. Young that fledge prematurely usually do not stay in the nest despite attempts to return them, and their survival rates away from the nest are low. When young birds are fully feathered and very alert, only observe the nest from a distance.
  • Avoid disturbing nests during bad weather as this can be stressful for the birds. If it is cold, damp, or rainy, postpone checking nests until another day.
  • Do not check nests at or after dusk, when females are returning, or have returned, to the nest for the night. The exception to this would be owls, which typically leave the nest at dusk.
  • Be careful of attracting nest predators. Whenever possible take a different route away from the nest site than the route you took to reach it. Walking back and forth to the nest along the same path leaves a dead-end trail that can lead predators directly to the nest.
  • Don’t touch the birds. In most instances it is illegal for you to touch or otherwise physically disturb an active nest or its contents.

If you have found a nest, why not consider monitoring it for NestWatch? NestWatch participants enter data into a centralized database that is used to help scientists learn more about nesting birds and bird populations. You can review the Nest Watching Manual to learn more. This is a fun way to enjoy birds and to contribute to our understanding of their ecology.

Q. I found a nest with eggs in it and no adult birds seem to be attending to it. I think it's abandoned, or I scared the parents away. What should I do?

A. Birds almost always return to their nest and resume incubating after they've been scared off. The parents may also periodically leave the nest to feed. This is especially true before all the eggs have been laid; many birds don't start incubating their eggs until after the last one is laid, which ensures that the eggs all hatch at about the same time. So, in most cases, the nest is fine and the adult birds will be back to incubate the eggs soon.

We don't advise that you try to hatch the eggs yourself. A federal license is required to work with native bird species, and hatching eggs successfully can be tough; it requires a specific temperature, humidity, and turning schedule.

To learn the safest ways to monitor bird nests and avoid disturbing the birds visit NestWatch. Here you can learn more about the code of conduct for monitoring a nest, and find guidelines for nest monitoring.

Q. What's good nesting material to offer birds?

A. Birds will often use nesting material that is offered to them to build nests, and to insulate roosting cavities in the winter. Some material, such as dryer lint, may seem desirable, but can actually be dangerous to birds. Pet fur should only be offered from pets that have not received flea or tick treatments. Take a look at our webpage Other Ways to Attract Birds for information and ideas about bird-friendly nesting material.

Q. After birds leave a nest, can I clean out the nest for future use?

A. We don't advise cleaning a used nest. It's better for most birds to rebuild a new nest each time. This reduces the prevalence of parasites, because some mites and lice lay eggs in nest materials, producing a whole batch of young parasites that will attack the next set of nestlings from the start.

However, if you are wondering what to do about a nest inside a nest box or birdhouse, NestWatch suggests cleaning out the box at the end of the season, though this isn't absolutely necessary; often birds will clean it out themselves.

You can find out more about construction, placement, and care of nest boxes from our NestWatch project and their All About Birdhouses site.

Q. I have wasps in my birdhouse. What should I do?

A. Wasps and bees seldom usurp boxes from nesting birds. They are mostly found in empty boxes. If these insects are found in a box, it is best to let them be and not take any active measures to exterminate them. Instead, wait to clean them out in the fall when the weather is cooler and their activity has halted. You can prevent wasps and bees from establishing themselves by applying a thin layer of soap (use bar soap) onto the inside surface of the roof. This will create a slippery surface between the insects and the roof of the box. For more information about maintaining nest boxes, visit Nestwatch