Bird flight

Bird flight is the primary mode of locomotion used by most bird species in which birds take off and fly. Flight assists birds with feeding, breeding, avoiding predators, and migrating.

Bird flight includes multiple types of motion, including hovering, taking off, and landing, involving many complex movements. As different bird species adapted over millions of years through evolution for specific environments, prey, predators, and other needs, they developed specializations in their wings, and acquired different forms of flight.

Various theories exist about how bird flight evolved, including flight from falling or gliding (the trees down hypothesis), from running or leaping (the ground up hypothesis), from wing-assisted incline running or from proavis (pouncing) behavior.