Exotic birds in a Russian zoo. Birds — a class of warm-blooded egg-laying vertebrates. Represent a well-distinct group, one of the most characteristic features of representatives which is the covering of feathers that protects the body from adverse changes in temperature and plays an important role during the flight. The ability to fly is the main feature of the bird (its absence in some species is a secondary phenomenon). The upper limb took the form of wings. Birds have a special structure of the respiratory and digestive system, which is closely linked to their ability to fly. Another distinctive feature is the presence of beak.

圖片編號： 77350914
拍攝者： Kusmina59