Two black-necked cranes fly over the Nianhu Lake in Huize County of Qujing City, southwest China's Yunnan Province, Dec. 13, 2012. A good many black-necked cranes chose to spend this winter on the wetlands near the lake thanks to the comfortable environment here. (Xinhua/Yang Zongyou)

Two black-necked cranes frolic on the Nianhu Lake in Huize County of Qujing City, southwest China's Yunnan Province, Dec. 13, 2012. A good many black-necked cranes chose to spend this winter on the wetlands near the lake thanks to the comfortable environment here. (Xinhua/Yang Zongyou)

A flock of black-necked cranes fly over the Nianhu Lake in Huize County of Qujing City, southwest China's Yunnan Province, Dec. 13, 2012. A good many black-necked cranes chose to spend this winter on the wetlands near the lake thanks to the comfortable environment here. (Xinhua/Yang Zongyou)