THE BIRDS

THE BIRDS

Birds make up the scientific class Aves. They are warm-blooded, egg-laying vertebrate animals that are covered with feathers and possess forelimbs that have modified to become wings. Birds also have scaly legs, and no teeth.
Many species undertake long distance annual migrations, and many more perform shorter irregular movements. Birds are social; they communicate using visual signals and through calls and songs, and participate in social behaviours including cooperative breeding and hunting, flocking, and mobbing of predators. The vast majority of bird species are socially monogamous, usually for one breeding season at a time, sometimes for years, but rarely for life. Other species have breeding systems that are polygynous or, rarely, polyandrous. Eggs are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching.
Birds must obtain a lot of food to provide the energy needed for flight. To capture, grip, and handle food, birds mainly use their bills. Bills are shaped to help birds feed quickly and efficiently.