A
nest is a structure built by certain animals to hold its
eggs, its offspring, or occasionally the animal itself. Although nests are most closely associated with birds, members of all classes of
vertebrates and some invertebrates construct nests. They may be composed of
organic material such as
twigs,
grass, and
leaves, or may be a simple depression in the ground, or a hole in a rock, tree, or building. Human-made materials, such as string, plastic, cloth, or paper, may also be used. Nests can be found in all types of
habitat.