Brown-headed gulls seen in Shaliu River in Gangca County of Qinghai

Two brown-headed gulls are seen in the Shaliu River in Gangca County of northwest China's Qinghai Province, July 29, 2020. (Xinhua/Zhang Hongxiang)

A brown-headed gull flies over the Shaliu River in Gangca County of northwest China's Qinghai Province, July 29, 2020. (Xinhua/Wu Gang)

A brown-headed gull flies over the Shaliu River in Gangca County of northwest China's Qinghai Province, July 29, 2020. (Xinhua/Wu Gang)

A brown-headed gull lands on the water surface of the Shaliu River in Gangca County of northwest China's Qinghai Province, July 29, 2020. (Xinhua/Zhang Hongxiang)

A brown-headed gull is seen in the Shaliu River in Gangca County of northwest China's Qinghai Province, July 29, 2020. (Xinhua/Zhang Hongxiang)

A brown-headed gull flies over the Shaliu River in Gangca County of northwest China's Qinghai Province, July 29, 2020. (Xinhua/Zhang Hongxiang)