There are many kinds of birds, second only to fish among vertebrates. 2 1 century There are more than 9,000 species of birds known all over the world, and there are more than 300 species of1in China alone, among which there are many bird species endemic to China.

About120 ~130 species of birds have become extinct. Compared with other terrestrial vertebrates, birds have many unique physiological characteristics. These birds are quite different in size, shape, color and living habits.

Extended data:

There used to be160,000 species of birds on the earth, and the tertiary period was the heyday of birds. During the four major ice ages in the Pleistocene, about 25% of birds became extinct. After the appearance of human beings in the late Pleistocene, one species of bird died out every 83 years on average. During the 300 years from 1600 to1900, 90 species of birds were extinct.

The endangered birds in China are black stork, white stork, crested ibis, yellow-bellied pheasant, black-necked crane, white crane, red-crowned crane, swan, cygnet and merganser.

Birds that are endangered in the world, such as: black-faced spoonbill, kakapo (KāGū), Indian vulture, Australian bird, North American waiting pigeon, rare bird species unique to Africa, gray crowned crane, and 10 species of Antarctic penguin are endangered.

Baidu Encyclopedia-Birds