A flock of ruddy shelducks perch at a park in Lhasa, capital of southwest China's Tibet Autonomous Region, Jan. 8, 2016. A good many migratory birds chose to live through winter in Lhasa. (Xinhua/Zhang Rufeng)

Bar-headed geese are seen at a park in Lhasa, capital of southwest China's Tibet Autonomous Region, Jan. 8, 2016. A good many migratory birds chose to live through winter in Lhasa. (Xinhua/Zhang Rufeng)

Black-headed gulls compete for food at a park in Lhasa, capital of southwest China's Tibet Autonomous Region, Jan. 8, 2016. A good many migratory birds chose to live through winter in Lhasa. (Xinhua/Zhang Rufeng)

A flock of bar-headed geese fly near the Potala Palace in Lhasa, capital of southwest China's Tibet Autonomous Region, Jan. 8, 2016. A good many migratory birds chose to live through winter in Lhasa. (Xinhua/Zhang Rufeng)

A flock of bar-headed geese perch at a park in Lhasa, capital of southwest China's Tibet Autonomous Region, Jan. 8, 2016. A good many migratory birds chose to live through winter in Lhasa. (Xinhua/Zhang Rufeng)