各种鸟类的特征（The characteristics of various birds）.docVIP

各种鸟类的特征（The characteristics of various birds） Aves is a class of vertebrate in biological taxonomy. The birds are bipedal, constant temperature, oviparous vertebrates, wearing a feathered forelimbs of wings, a hard beak. Birds body size, there is also a small humming bird ostrich and EMU (a body found in Australia large flightless bird). At present, there are more than 9000 species of birds known all over the world. There are more than 1300 species recorded in China, among which are endemic birds of China (see list of endemic birds in China). About 120-130 species of birds have become extinct. Compared with other terrestrial vertebrates, birds are a species with many unique physiological characteristics. Classification of birds 1. Youqin Swimming is the love in the water feeding and habitat of birds. Youqin variety, wildly distributed in china. Including geese, ducks, gulls and so on. Such as swans, geese, mandarin ducks, pelicans, gulls and so on. The geographical distribution of these different Youqin, as the most common area of Beijing Youqin: Swan, Little Swan, mallard, smew, goosander and blackened cormorant etc.. Birds often choose Lake place to rest, to fish, shrimp and aquatic plants for food. Youqin breeding nest flat plate, can be floating in the water, the water floating nest which is peculiar to youqin. When they fly, they stretch out to the back of the body, flying very fast, and webbed toes between them. Most of its mouths are broad and flat, and are good at swimming and diving. Swans, geese, wild duck and other moulting, often also feathers fall off, and for a few weeks can flight, predation ability is greatly reduced, vulnerable, effective protection needs during this period. Wild geese flying general arranged in human or a shaped queue, while flying a babble, babble. 2. waders Waders are those that adapt to life in the marsh and waterside birds. Their legs are very slender, and their neck and toes are longer. They are suitable for wading and swimmin