A bird's primary consideration when choosing a nesting site is security. Protection from predators and proximity to food is of vital importance to the success of a bird's offspring.
The one-foot-long hanging nest of a Bushtit resembles an Oriole’s nest and is woven out of a variety of materials including mosses, lichens, leaves and spider's webs.
Chimney Swifts build their nest in chimneys, tree cavities and on walls by gluing twigs together with their sticky saliva.
Chipping Sparrows line their nests with animal hair, preferably horse hair.
Barn Swallows line their nests with feathers.
Since American Crows do not breed until they are between two to four years old, they often stay with their parents and help them raise the young of following years. Family groups may include over a dozen individuals from five different years.
The Cactus Wren builds an elaborate gourd-shaped nest in about ten days, and may fuss with improvements for another several weeks.