nest

A structure built by an animal for holding eggs, raising young, or sheltering — from the woven cup of a songbird to the mounded vegetation of an alligator to the excavated burrow of a kingfisher. A nest is architecture shaped by instinct and refined by experience. Some nests are used once and abandoned; others are maintained for decades. The bald eagle's nest is the largest of any North American bird, rebuilt and expanded each year until it can weigh two tons. A nest is also a sign — its size, materials, location, and construction identify the builder as precisely as a fingerprint.