Ask Anne

Anne Hobbs, the Lab's public information specialist, shares these questions from her email bag, along with her answers.

Brown Pelicans dive from as high as 65 feet without damage to their eyes.

Brown Pelican by William Newton/CLO

Blind Pelicans

Q: 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.

--Stacia Hendricks,
Brunswick, Georgia

A: 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

Q: 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.

--Mary Batten,
Smithfield, Virginia

A: 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.

A Blue Jay--bald, but not alone. Many people call Anne about bald birds in the fall.

Blue Jay by Ann Morrison/Project FeederWatch

Bald Birds

Q: There's a strange bird at my feeders. It looks like a Blue Jay but its head is almost black. What is it?

A: In fall, we receive many inquiries about bald birds, especially Northern Cardinals and Blue Jays. In late summer and fall, when birds molt, they usually grow and replace feathers gradually, but occasionally they drop all the feathers on their head at once. Many of these strange-looking birds may be juveniles undergoing their first molt. It is also possible that the baldness is caused by feather mites or lice, or some environmental or nutritional factor.

For more photos and information about bald birds, visit www.birds.cornell.edu/pfw and click on "About Birds and Bird Feeding."