All birds are already here, as the saying goes in spring. With their songs and chirps, they mark their territory and attract females. Birds are also acrobats of the skies! Hummingbirds can fly backwards, and macaws use their beaks as climbing aids. Courtship, bird weddings, and bird migrations are legendary. "What is What" visits a bird caretaker and interviews the ancient bird Archaeopteryx, tells stories of master singers and colorful parrots, rivals and territorial battles, the construction of a nesting aid and a feeding house, and how one can become a birdwatcher themselves.