High-speed wings sweep back and have a slender tip, to avoid drag at high speeds. These wings are efficient at high speeds for such birds as swifts that feed on the wing. Soaring wings are long and narrow, with no wing slots. While these wings are not maneuverable, they are useful for long periods of gliding, such as with albatrosses. High-lift wings are broad, with wing slots, to allow predatory birds to carry prey.
Birds are quite active and therefore eat a lot.
Birds use beaks and tongues for eating, e.g., woodpeckers vs. hummingbirds. Waste is expelled through a cloaca . The bird heart is modified from the reptilian heart and now has four separate chambers , with no ventricular septum. The right atrium receives venous blood from the body and sends it to the right ventricle, where the blood is sent to the lungs. As the air is breathed out of the lungs, some of this fresh air sac air enters the lungs.