This photo taken on Dec. 16, 2024 shows ruddy shelduck at Caohai National Nature Reserve in the Yi-Hui-Miao Autonomous County of Weining, southwest China's Guizhou Province. Caohai National Nature Reserve is an important wintering ground for black-necked cranes. In recent years, the population of wintering black-necked cranes has increased, thanks to the local authorities' efforts in ecosystem restoration and patrolling. Currently, the reserve is home to nearly 100,000 wintering migratory birds, including 2,500-plus black-necked cranes as well as other species such as grey cranes and bar-headed geese. (Photo by Shen Guangyong/Xinhua)