Red-crowned cranes fly over Zhalong National Nature Reserve in Qiqihar, northeast China's Heilongjiang Province, Dec 19, 2019. More than 200 captive-bred red-crowned cranes spend the winter at Zhalong National Nature Reserve this year thanks to appropriate measures of artificial breeding and animal protection. (Xinhua/Liang Dong)

Red-crowned cranes fly over Zhalong National Nature Reserve in Qiqihar, northeast China's Heilongjiang Province, Dec 19, 2019. More than 200 captive-bred red-crowned cranes spend the winter at Zhalong National Nature Reserve this year thanks to appropriate measures of artificial breeding and animal protection. (Xinhua/Liang Dong)

Red-crowned cranes are seen at Zhalong National Nature Reserve in Qiqihar, northeast China's Heilongjiang Province, Dec 19, 2019. More than 200 captive-bred red-crowned cranes spend the winter at Zhalong National Nature Reserve this year thanks to appropriate measures of artificial breeding and animal protection. (Xinhua/Liang Dong)

Red-crowned cranes fly over Zhalong National Nature Reserve in Qiqihar, northeast China's Heilongjiang Province, Dec 19, 2019. More than 200 captive-bred red-crowned cranes spend the winter at Zhalong National Nature Reserve this year thanks to appropriate measures of artificial breeding and animal protection. (Xinhua/Liang Dong)