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Unusual and Interesting Questions

We occasionally receive questions that I find to be unusual, fun or extra-interesting. Here are a few of my favorites.

I have birds nesting under my porch, and there are millions of insects coming from the nest and getting all over the porch. They look like fine pepper flakes. They are round and black, gray, or transparent. What are they and how can I get rid of them?

The insects are nest mites. Try using Pyrethrum insect powder (a natural pesticide) in the nest and the affected areas of the porch. Cleaning the porch with standard cleaners should also help.

I am an arborist attempting to solve a problem which I believe involves Acorn Woodpeckers. I have seen several of them in the vicinity of a live oak tree I'm trying to save.  It's a large old tree, and has severe dieback of the smaller limbs and twigs.

Upon climbing the tree, I found there are hundreds of almost dime-sized holes in the bark (the wood is not penetrated).  Almost all the holes are in the upper half of the canopy and they are only on the upper surface of limbs between 3 to 8 inches in diameter. Some appear to be one or two years old and others are quite fresh. Some are oozing white foam.

There are no signs of insects in or on the bark. No tunnels and no frass. The holes are nowhere near deep enough to store acorns. Could this be Acorn Woodpeckers activity?  Why are they doing it?

—Mark O'Brien
Menlo Park

I referred this question to Dr. Walter Koenig, an Acorn Woodpecker expert at the Hastings Natural History Reservation in California. He wrote the response below.

Yes, it definitely looks like Acorn Woodpeckers. Along with flycatching and storing acorns, they also do a fair amount of sapsucking, except that the holes they make are not distributed in straight lines the way that the ones made by sapsuckers are but instead distributed almost randomly throughout the limb, pretty much like their acorn storage holes. The goal is to tap into the active layer where the sap is flowing through the tree—apparently something of a tricky and delicate act to accomplish.

In my experience, only a small proportion of these holes are "active" at any one time, so at certain times of the year birds will spend a significant amount of time climbing around a particular tree drinking from the relatively small number of holes from which sap is dripping. I actually analyzed the sap once and found that it contains a rather nutritious combination of amino acids and various other goodies.

Here at my study site in Monterey County the main sapsucking seasons are mid-winter (January) and mid-summer (July). Not sure why, or how exactly this matches with the timing of sap flow in some of those trees. Of course, the tree you sent pictures of is a coast live oak, which, being evergreen, should have at least some sap in it at almost any time of year.

Last but not least, I certainly doubt that this activity hurts the tree, except perhaps very rarely. As you can see, those holes are distributed in a way that is unlikely to girdle the limb in any effective manner, so the odds of them hurting the tree, except insofar as the birds are getting some of the sap, is pretty low.

Gay birds?
Can birds be gay?

Although rare, homosexuality has indeed been observed in birds. One fairly famous example is the pair of Chinstrap Penguins at the Central Park Zoo, Roy and Silo. These two males act as a heterosexual couple would, vocalizing, courting, and mating. The two even started to incubate a rock, diligently keeping it warm in the folds of their abdomens. Their chief zookeeper eventually gave them a fertile egg—which they raised into a healthy chick. Roy and Silo have refused female companionship, and apparently the female penguins aren’t interested in them either.

Some people may argue that this homosexual bond arose because the penguins are kept in captivity and are thus not in their natural environment. But homosexual birds are found in the wild as well—including species of gulls, terns, geese, swans, parakeets, and even ostriches—that have formed homosexual pair bonds. Many of these pairs manage to “adopt” and raise broods as well.

The general rule of nature is to promote and pass along your genes—which most animals do by producing their own young with a member of the opposite gender. Why are some individuals opting for this “alternative” lifestyle? Some scientists theorize that homosexual individuals may help their genes by aiding their kin’s offspring. Others suggest that, in the case of social species, it aids in bonding and social status.  We still don’t know all the reasons.

Scientific Name
How is the scientific name for Bald Eagle, Haliaeetus leucocephalus, pronounced?

The name is pronounced hah-lee-ay-EET-us loo-coh-SEH-fah-lus. The first part of the name comes from hals (the sea) and aetos (an eagle) and leucocephalus means white-headed.

Flying Poop
I have been asked to find out if Canada Geese, um, poop while they fly. I'm sure you have more important issues, but this is very important to the seven-year-old who goes to the driving range with me.

Birds are certainly capable of pooping while flying. They often poop just before taking off, perhaps to lighten their load. Although this might not reassure your seven-year-old, you might also mention that in some cultures people believe that is very good luck to be hit by bird poop.

Blind Pelicans
I hear that Brown Pelicans frequently die of blindness because they develop cataracts as a result of their diving behavior. I find this to be preposterous and wonder if you have any light to shed on this subject.

The good news is that pelicans do not become blind from the impact of repeated diving, even though they may plunge into the water from as high as 65 feet. The bad news is that they do sometimes lose their vision for other reasons, including infections resulting from disease or hook and line injuries.

These cases are relatively rare, however, compared with other causes of injury and mortality. Wendy Fox, executive director of the Pelican Harbor Seabird Station in Florida, has seen only several blind pelicans out of some 10,000 pelicans that came through the rescue and rehabilitation center in the past 25 years. Wendy says that about 90 percent of all injuries were caused by fish hooks from fishing lines.

Other causes of mortality for Brown Pelicans include starvation because of scarcity of fish during cold temperatures and the stress of migration, especially for younger birds.

Pelicans have several adaptations to diving, including air sacs beneath the skin on their breast that serve as cushions and floats. While diving, they also rotate their body to the left, probably to avoid injury to their trachea and esophagus, which are on the right side of neck.

Bird Belly Buttons
Recently I wrote a book for children called Who Has a Belly Button? The book is about mammals and why mammals have belly buttons. A reader has written that birds also have belly buttons. When I was doing my research for the book, I did not find any reference to belly buttons in birds. I would appreciate it very much if you could tell me whether birds do indeed have belly buttons.

Thanks for the delightful question. In the egg there is a cord that attaches the developing embryo to the yolk sac. When the bird hatches, there is a residual scar where the cord used to be. While the bird is a nestling, you can still see what would be the avian equivalent of a belly button. However, as the bird develops, that area becomes more compact and in an adult bird there is virtually nothing to be seen of what once was the scar. So technically baby birds have belly buttons, but unlike the belly buttons of humans, these go away as they grow up.