A flock of Mandarin ducks fly over the Diluo lake in Jiangkou County of Tongren City, southwest China's Guizhou Province. Migrant Mandarin ducks enjoy winter in Guizhou. (Photo: China News Service/Li He)

A flock of Mandarin ducks fly over the Diluo lake in Jiangkou County of Tongren City, southwest China's Guizhou Province. Migrant Mandarin ducks enjoy winter in Guizhou. (Photo: China News Service/Li He)

A flock of Mandarin ducks swim in the Diluo lake in Jiangkou County of Tongren City, southwest China's Guizhou Province. Migrant Mandarin ducks enjoy winter in Guizhou. (Photo: China News Service/Li He)

A flock of Mandarin ducks swim in the Diluo lake in Jiangkou County of Tongren City, southwest China's Guizhou Province. Migrant Mandarin ducks enjoy winter in Guizhou. (Photo: China News Service/Li He)