Ornithologists have theorized that birds first began to build nests when they were unable to locate natural cavities. Of the 470 perching (passerine) birds in North America, about 25 percent use holes or build domed structures, while the remainder has open nests constructed from scratch. These open nests vary greatly in regard to adaptation to the immediate environment as well as to the needs of individual species.
An illustrated book such as "A Field Guide to Bird's Nests" (1975) by Hal H. Harrison will allow you to identify many of the nests you can locate on your property or immediate vicinity.
Do not disturb nesting birds. Observe them from a distance using binoculars or a spotting scope.
Birds:Go with a birding group to learn species and vocalizations
If you spot a nest situated in a shrub or tree fork or out on a horizontal limb that has a mud-lined interior, chances are it was built by a female robin. She shaped the mud to fit her body while it was still moist. While in the nest-building phase a female robin will often build many nests side by side, although she normally lays eggs in just one of them.
Since the red-eyed vireo is one of the most common breeding birds in the eastern broadleaf forests, it's not surprising that their nests are among those most frequently encountered. Look for a deep-cupped, pouch-like structure constructed in the horizontal fork of a slender tree branch about 10-20 feet above the ground.
A red-eyed vireo nest demonstrates the close relationship between birds and the habitats in which they choose to breed. They are constructed from various grasses, strips of bark from birch, and vine tendrils.
It is often situated directly beneath an overhanging leaf that serves as a roof for rain protection and camouflage against predators. The outside of the nest is both "camouflaged" and "decorated" with strands of an old man's beard ("usnea," a lichen that resembles Spanish moss ) and various other lichen species.
WNC Nature Center Notes:Creating a bird haven at home
Few would deny that birds camouflage their nests with local materials so that it will blend into the immediate surroundings in order to avoid predators. I also feel that birds have an aesthetic sense that leads them to build and camouflage in a decorative manner. And it is, after all, the most artfully contrived structure that blends most effectively into the landscape.
The most common question I receive regarding bird nests is "Where do hummingbirds build their nests?" Well, they build them about 10-20 feet above ground level on a twig or small branch that slants downward. Just over an inch wide and 1.5 inches high, they're difficult to spot because of their size and the intricate decorative camouflage of greenish-gray lichens applied to the outside of the nest. Viewed from the ground, a ruby-throated hummingbird's nest looks exactly like a mossy knot on a limb.
If there's a more beautiful nest in North America than the one constructed by the female Baltimore oriole, I have yet to see it. As described by Donald and Lillian Stokes in their "Guide to Bird Behavior" (vol. II, 1983), it is almost totally the work of the female. The male's assigned task is to find a nearby perch from which he can sing while she works. Male and female Baltimore orioles are quite different in appearance. (Elizabeth's illustration depicts a male inspecting his partner's handiwork.)
Suspended from the tip of an overhanging branch, it requires 5-8 days of nest building. Using long fibers to create a suspended frame, she then lines the interior of the structure with soft materials like feathers, grasses, and wool.
George Ellison is an award-winning naturalist and writer. His wife, Elizabeth Ellison, is a painter and illustrator who has a gallery studio at 155 Main St., Bryson City. Contact them at info@georgeellison.com or info@elizabethellisongallery.com or write to 3880 Balltown Road, Bryson City, NC 28713.