SPRING 2008/VOLUME 22, NUMBER 2
FAQs about Nests
Q. I started a nest collection. How can I identify them all?
A. As fascinating as nests are, Americans are not legally allowed to collect them. The Migratory Bird Act prohibits anyone without a permit from possessing dead or live birds or their feathers, eggs, or nests. This law was enacted to protect birds from egg and nest collectors and people who decimated bird populations for their plumage. Collecting photos of bird nests takes up far less space and unlike nests, photos never harbor mites!
Identifying nests after the birds have left can be tricky, but help is here! See Tina Phillip’s "Whose Nest Is It?" in BirdScope, page 4-5.
Q. Do all birds sleep in nests?
A. Nests are built not to serve as beds for sleeping birds but as egg incubators and baby cradles. With the exception of some cavity nesters, after most baby birds fledge, they no longer return to the nest at all. American Robin fledglings, for example, follow their father every evening to a gathering place called a roost to sleep in branches. Where’s the mother? If it’s early in the season, she’s spending her nights incubating a new batch of eggs. If this is her last brood for the season, she may join them in the same roost.
Q. How do birds learn how to build nests?
A. Most birds know, probably from a combination of instinct and imprinting on the nest they grew up in, how to build their first nest, but their skills improve with practice. In a few species, such as the Florida Scrub-Jay, year-old birds sometimes remain with their parents, helping them raise the next year’s young. This gives the older siblings opportunities to observe exactly what’s involved in building a nest and raising babies.
Q. How do birds make their nest just the right shape?
A. Many birds construct their nest from the inside, shaping it with their body. Female American Robins plaster grasses, small twigs, and other fibers together with mud. As they build, they frequently rotate their body within the growing structure to smooth and shape it. The Baltimore Oriole clings to the supporting twig, often head down, and while holding a fiber makes rapid thrust-and-draw movements with her mandibles. Once she’s woven a small section, she starts clinging to it, and ends up working from the inside as the nest is completed. She doesn’t appear to specifically tie knots, and the stitching of a closely-examined nest appears to be random, but the end result is a tightly woven structure. Imagine doing all that with just your mouth!
Q. I have a pair of Eastern Phoebes nesting on my house. My children would love to watch the growing family, but I’m afraid if we visit the nest we may cause the parents to abandon it. Is there a safe way to watch nesting birds?
A. Very few birds are bothered by prudent nest observation (Eastern and Western Meadowlarks are notable exceptions), and by safely monitoring nests we can contribute a lot of important information that helps conservation scientists. The easiest way to do this is to participate in NestWatch. Learn about the Nest Monitor's Code of Conduct and learn more about NestWatch on the web at www.nestwatch.org.
Q. Last spring I watched Greater Prairie-Chickens from a blind. Later in the morning when the chickens started leaving, suddenly Tree Swallows came in, flying back and forth just above where the prairie chickens had been dancing. Do prairie chickens have lice or something that the swallows were feeding on?
A. Like all birds, prairie-chickens do, indeed, harbor a few lice and mites, but these parasites stick tight to their hosts, and aren’t normal food for swallows. But during their dancing, prairie-chickens sometimes squabble, and they also take time out for preening. During these times, they often drop small body feathers. Tree Swallows line their nests with feathers, and know how to capitalize on a regular supply! So they fly low and pluck them up as they go.
Q. Why do swallows line their nests with feathers?
A. The rate of growth and general health of Tree Swallow nestlings is directly related to the number of feathers lining their nests. This may be because of the added insulation the feathers provide, or because the feathers provide a barrier protecting the babies from parasites, or some other reasons not fully understood. But because it is so important to Tree Swallow nesting success, the adults spend a lot of time searching out and gathering feathers. (You can learn more about this in David W. Winkler's 1993 paper in the Auk (110:29-36), "Use and importance of feathers as nest lining in Tree Swallows (Tachycineta bicolor)").
Q. One day I looked out on my porch and a little bird was plucking fur from my golden retriever! What was that about?
A. Chipping Sparrows, Tufted Titmice, and some other birds line their nests with fur from animals. Chipping Sparrows in particular seem to prefer horse hair and dog fur. One Loggerhead Shrike in Florida built its nest almost entirely of hair from a nearby dead cow.
Q. What are some other weird things birds have built nests from?
A. A Warbling Vireo in California built its nest entirely of facial tissue. Chihuahuan Ravens occasionally build their nests entirely of barbed wire. A Ruby-throated Hummingbird on Long Island, New York, built its nest entirely of fiberglass roofing insulation. A Carolina Wren constructed a nest mostly of hairpins. Double-crested Cormorants off the coast of Labrador salvaged from a sunken trading vessel pocketknives, pipes, hairpins, and combs to construct their nests. A Canyon Wren in Fresno, California, constructed its nest on the beam of an office building. The nest was made entirely of office supplies including paper clips, pins, rubber bands, thumbtacks, shoelaces, needles, wire, matches, and toothpicks; it weighed 2.5 pounds.
Q. My robins nested on my windowsill and now they’ve left. Should I throw out the old nest?
A. If it’s still during the breeding season, you should probably leave it there. It’s illegal to disturb active nests, and the robins may renest there. Also, sometimes Eastern Phoebes nest on top of an old robin nest. At the end of the season, you can remove the nest.
Q. Should I clean out my bluebird boxes in the fall?
A. NestWatch recommends, in many cases, leaving the nest boxes as they are. The North American Bluebird Society recommends removing nests as soon as fledglings have left a box during the summer.
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