Shuanglong, a man of Mongolian ethnic group, and his son look at a newly-built nest of upland buzzard on their way to the Hulun Lake in New Barag Right Banner of the Hulun Buir City, north China's Inner Mongolia Autonomous Region, April 13, 2019. (Photos:Xinhua)

Shuanglong, a man of Mongolian ethnic group, and his son look at a newly-built nest of upland buzzard on their way to the Hulun Lake in New Barag Right Banner of the Hulun Buir City, north China's Inner Mongolia Autonomous Region, April 13, 2019. (Photos:Xinhua)

Shuanglong, a man of Mongolian ethnic group, and his son look at a newly-built nest of upland buzzard on their way to the Hulun Lake in New Barag Right Banner of the Hulun Buir City, north China's Inner Mongolia Autonomous Region, April 13, 2019. (Photos:Xinhua)

Shuanglong, a man of Mongolian ethnic group, and his son look at a newly-built nest of upland buzzard on their way to the Hulun Lake in New Barag Right Banner of the Hulun Buir City, north China's Inner Mongolia Autonomous Region, April 13, 2019. (Photos:Xinhua)