Fascinating Facts about Nesting Birds

From the Cornell Lab of Ornithology Home Study Course

• A Royal Albatross raises at most one fledgling every two years, but the adults’ annual survival rate is over 95 percent.

• Eleonora’s Falcon in the eastern Mediterranean times nesting for late summer, capitalizing on the plethora of migrant land birds passing through the falcon’s range right when its young require the most energy.

• Moving nest sites: an Ash-throated Flycatcher in Colton, California nested in a crevice in an active steam shovel that moved up to 200 feet a day. A Barn Swallow nested on a slow-moving narrow-gauge train in British Columbia. Both Prothonotary Warblers and Tree Swallows have successfully nested on ferryboats moving back and forth daily across rivers.

• Odd nest materials: 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, entirely of office supplies including paper clips, pins, rubber bands, thumbtacks, shoelaces, needles, wire, matches, and toothpicks. The nest weighed 2.5 pounds.

• One Loggerhead Shrike in Florida built its nest almost entirely of hair from a nearby dead cow.

• Tufted Titmice pluck hair from living opossums, woodchucks, squirrels, and people.

• Black-capped Chickadees may grab hair from sleeping raccoons.

• Barn Swallows may make more than 1200 trips carrying a mouthful of mud to construct their nest.

• Black Woodpeckers in Eurasia must hammer on a tree about 100,000 times to excavate their nest cavity.

• One Altamira Oriole nest in Mexico contained 3,387 pieces of grass, many of which were three to four feet long.

• Large nests may be used year after year by a succession of different pairs. Osprey nests have been used for more than 40 years.

• One large platform nest of a White Stork in Germany was occupied from 1549 through at least 1930.

• A single nest in a tall chestnut tree near Saybrook, Connecticut, was built and used one breeding season by a pair of Cooper’s Hawks, the next year was taken over by Great Horned Owls, the following year was taken over by Red-tailed Hawks, and the following year by Barred Owls.

• Many tropical birds nest on or near the nests of aggressive wasps or in acacia trees tended by aggressive ants, both of which mercilessly attack a large variety of predators. No one yet understands how or why these nesting birds are spared by these fierce insects.

• In the Tundra, Snow Geese, Brant, and Common Eiders often nest near Snowy Owls, whose presence discourages attacks by arctic foxes.

• Water Thick-knees of Africa nest along sandy shorelines near breeding crocodiles.

• A variety of tropical birds nest inside termitaries (active termite nests). As a bird digs into the mound, the termites seal the exposed walls so that the bird’s nest and the termites’ chambers aren’t in direct contact. Some termitaries also house colonies of aggressive, biting ants which may either directly attack potential predators or discourage predators with their distinctive odor.

• Kirtland’s Warblers nest only on the ground in grasses beneath the living lower limbs of pines, usually jack pines between 6 and 18 feet tall.

• Even in species where nests are found or built by males, the female ultimately has veto power.

• The Oilbird of northern South America builds a nest from regurgitated fruits and seeds mixed with the bird’s own excrement. The nest grows higher each year as more material is added.

• Swifts use sticky saliva to construct their nests against vertical structures. The African Palm-Swift actually glues its eggs to the nest, incubating them from a vertical position. The Edible-nest Swiftlets of Southeast Asia often build their nests entirely of saliva. These are the nests which serve as the primary ingredient of bird’s-nest soup.

• Cactus Wrens nest within the arms of a spiny cholla cactus, providing them with protection from both the elements and predators.

For permission to reprint all or part of this article, please contact Laura Erickson, editor, Cornell Lab of Ornithology, 159 Sapsucker Woods Rd., Ithaca, NY, 14850. Phone: (607) 254-1114. email: lle24@cornell.edu