Red-crowned cranes fly over a lake at the Xianghai National Nature Reserve in Tongyu County of Baicheng City, northeast China's Jilin Province, April 15, 2014. (Xinhua/Lin Hong)

Red-crowned cranes fly over a lake at the Xianghai National Nature Reserve in Tongyu County of Baicheng City, northeast China's Jilin Province, April 15, 2014. (Xinhua/Lin Hong)

Red-crowned cranes are seen at the Xianghai National Nature Reserve in Tongyu County of Baicheng City, northeast China's Jilin Province, April 15, 2014. (Xinhua/Lin Hong)

Red-crowned cranes are seen at the Xianghai National Nature Reserve in Tongyu County of Baicheng City, northeast China's Jilin Province, April 15, 2014. (Xinhua/Lin Hong)