Four big swans fly over in the Qinghai Lake (February 28 perturbation).

In Qinghai Lake in Qinghai Province, the ecological environment improved significantly in recent years, came the big swan quantity which here survived the winter gradually to increase, becomes on the Qinghai-Tibet Plain the vitality abundant, makes one forget to return "the Swan Lake". (Xinhua Xu Hao/Photo)

Crowd of big swans play in Lake Qinghai (on February 28 to absorb). (Xinhua Xu Hao/Photo)

The big swan (on February 28 absorbs) in the Lake Qinghai sky soaring. (Xinhua Xu Hao/Photo)

Editor: Carolyn