Stork

Storks are large, long-legged, long-necked wading birds with long, stout bills. Storks tend to use soaring, gliding flight, which conserves energy. Soaring requires thermal air currents.
Their nests are often very large and may be used for many years. Some nests have been known to grow to over two metres in diameter and about three metres in depth.
Storks were once thought to be monogamous, but this is only partially true. They may change mates after migrations, and may migrate without a mate.