Many of the questions the Lab receives are seasonal in nature. Here are several that we often hear about in autumn.

Bird Health

Bald Birds

Q. I’ve been seeing a bald cardinal at my feeder. Is it sick?

A. In fall, we receive many inquiries about bald birds, especially Northern Cardinals and Blue Jays. In late summer and fall, when a bird molts, it usually grows and replaces all its feathers gradually, but occasionally a bird loses all the feathers on its head at once. The result is a very strange looking bald bird! Don’t worry--usually the feathers grow back just fine.

It is possible that the baldness is caused by environmental or nutritional factors, feather mites, or lice. To read more and take a look at photos of other bald birds, visit the “Bald Birds” page on the Project FeederWatch web site.

House Finch Eye Disease

Q. I’m suddenly seeing a lot of House Finches with red, swollen, and weepy eyes. What’s wrong with them?

A. The sick House Finches are probably afflicted with Mycoplasmal conjunctivitis, otherwise known as House Finch Eye Disease. In early fall, the prevalence of this infection increases dramatically, and bird watchers may start to find many more sick birds at their feeders. To read more about this disease and to learn about the citizen science project that attempts to track and understand it, please visit the House Finch Disease Survey.

Any time you see a bird that is clearly sick at your feeders, it's a good idea to do a couple of things. The first is to bring your feeders in and clean them thoroughly with a 10% bleach solution. Then wash with hot soapy water and rinse well. Dry thoroughly before putting seed back into the feeders. That will help protect the rest of the birds at your feeders. Even if the sick bird doesn't usually feed from the ground, it is a good idea to clean up the seed cases from the ground below your feeders as well. 

Hawks and Owls

Hawks at Feeders

Q. We have a hawk that comes to our yard on a regular basis, and yesterday he got a Mourning Dove. How can I get rid of him and keep the songbirds and doves?

A. Like the other birds, the hawk is coming to your yard because there is a source of food. If you want to discourage the hawk, you'll have to take your feeders down for a few days to disperse the hawk’s food source--smaller birds. In the wild, birds face constantly fluctuating food supplies, so songbirds, doves, and hawks alike will survive by finding food elsewhere. Try putting your feeders up again in a week or two. The songbirds and doves will come back but, with luck, the hawk will have found better hunting grounds somewhere else. You can learn more about feeder problems and solutions at our Project FeederWatch web site.

Hummingbirds

Rufous Hummingbirds

Q: Is it normal to see Rufous Hummingbirds in central Arizona during the summer?

Yes. These birds leave their breeding grounds in the northwest United States and Canada around mid-July and head south. You can see this for yourself by exploring the data for Arizona at eBird,  a joint project of the Cornell Lab of Ornithology and National Audubon Society. You’ll notice a peak in numbers during July to September in Arizona.

Curious about other areas or other hummingbird species? You can look up that information using eBird too. In addition to exploring the data, I hope you’ll enter your own sightings into eBird. It’s free, fun, helps you keep track of your own birds, and enables you to contribute information that other birders, scientists, and educators can use.

Identification

Flocks

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

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

Migration

Where Have All the Robins Gone?

Q. What happened to all the robins? I’m not seeing them any more.

A. Each year in late summer and fall, robins leave the territories where they’ve raised their young. They spend fall and winter in flocks, traveling to places where they can find more food. In fall, we receive questions from people in some areas who are wondering where the robins have gone, and questions from people elsewhere who are incredulous because they’ve been inundated with large flocks of robins.

By flocking, the robins benefit by having more eyes to look out for predators and to find food. You probably won’t see individual robins again until spring when the demands of finding and defending a territory cause them to leave the flock and strike out on their own.

Although robins are one of the most familiar and widespread birds in North America, their patterns of movement are poorly understood. In fall, their migrations are often influenced by the availability of fruit, but in spring they move in response to the availability of soil invertebrates, such as earthworms. Their numbers in particular places may vary from year to year.

Robin sightings reported by participants of the Great Backyard Bird Count show that robins tend to avoid areas with deep snow cover. This makes sense, since they often search for food in the soil. You can read more about these results on the Great Backyard Bird Count web site.

You can help scientists document the seasonal movements of robins by participating in the Great Backyard Bird Count in February or by reporting your sightings to eBird. This online checklist program allows you to keep track of your own bird lists, see the changes in numbers throughout the year, and explore maps showing where else the birds are being seen.

For more information about robins, including a map showing their summer and winter ranges, visit our Online Bird Guide.

Hungry Hummers?

Q. I have been told that I should stop feeding hummingbirds in the fall so that they can begin their southern migration. Is this correct?

A. That's actually a myth. A number of factors trigger the urge for birds to migrate, but the most significant one is day length. When the days get shorter, the hummingbirds will move on, regardless of whether there are still filled feeders available for them.

We do, however, encourage people to keep their hummingbird feeders full for several weeks after they have seen the last hummer just in case there are stragglers in need of additional energy before they complete their long journey south.

Learn more about feeding hummingbirds by visiting our pages on feeding and attracting birds.

Birds and Hurricanes

Q. How do hurricanes affect migrating birds, and is there anything we can do to help the birds that have been negatively affected?

A. Each year, migratory birds cross the Gulf of Mexico during the hurricane season. Birds wait for favorable winds and weather before taking flight, so they won’t try to fly during a hurricane. If a migrant lands at a spot that has been devastated by storms, it will continue onward in search of better stopover areas.

Unfortunately, sometimes migratory birds get caught in bad weather while crossing open water. 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. Preserving critical coastal habitats is important for exhausted migrants.

Resident birds in hurricane areas also suffer when their food supplies, such as fruits and berries, are stripped from trees and shrubs.

Birds and hurricanes have coexisted for millennia, and given the chance, healthy bird populations can rebound from the effects of natural disasters. Unfortunately, humans are making this difficult for some birds because we have destroyed so much of their original habitats. With fewer birds and fewer places where they can live, hurricanes pose greater threats to vulnerable bird populations. For this reason, one of the best things we can do to protect birds from hurricanes is work to ensure that there are enough birds and places for them so they have the opportunity to rebound.

BirdNotes--Fall Migration Mysteries
More information on fall migration is available in this issue of BirdNotes (PDF document).

Woodpeckers

Damage to Homes

Q: A woodpecker has been making holes on my house. I don’t want to harm the bird, but I’ve tried to get rid of it, with no success. What should I do?

A: No matter how much people enjoy seeing woodpeckers at their feeders or on the trees in their yard, we know from the many inquiries receive that people do not like it when those same woodpeckers drum on their homes!

To help find solutions, researchers at the Cornell Lab of Ornithology conducted a survey of woodpeckers and the damage they cause to homes. Their goal was to better understand the behavior, determine which types of home are at greatest risk, and suggest some safe deterrents. You can read all about the results of this study at our web site, “Woodpeckers: Damage, Prevention, and Control.”