By Chen Liang | China Daily | Updated: 2021-01-30 09:23 Share CLOSE Groups of black-headed gulls spend winter in Yilong National Wetland Park in Shiping county, Yunnan province. [Photo provided to chinadaily.com.cn] It was first seen this winter in a pond in the Grand Canal Forest Park in Beijing's Tongzhou district on Dec 26. But after most, if not all, freshwater bodies including reservoirs and ponds froze due to the sharp drop in the temperature in early January, it, along with other waterbirds, moved to rivers which remained relatively ice-free due to the water flow. It was last sighted on the Wenyu River on the border of Chaoyang and Shunyi districts of Beijing.