A black stork flies over the Beichuan river wetland park in Xining City, northwest China's Qinghai Province, Dec. 6, 2020. Recently, the wetland park saw two black storks, a migratory bird species under first-class protection in China. There are only around 3,000 black storks now worldwide.(Photo: Xinhua)

A black stork is seen at the Beichuan river wetland park in Xining City, northwest China's Qinghai Province, Dec. 6, 2020. Recently, the wetland park saw two black storks, a migratory bird species under first-class protection in China. There are only around 3,000 black storks now worldwide. (Photo: Xinhua)

A black stork forages at the Beichuan river wetland park in Xining City, northwest China's Qinghai Province, Dec. 6, 2020. Recently, the wetland park saw two black storks, a migratory bird species under first-class protection in China. There are only around 3,000 black storks now worldwide. (Photo: Xinhua)