People watch black-headed gulls on a dam in Kunming, capital of southwest China's Yunnan Province, March 15, 2016. Tens of thousands of black-headed gulls fly to Kunming from northern China every winter in the past 32 years. (Xinhua/Lin Yiguang)
People watch black-headed gulls on a dam in Kunming, capital of southwest China's Yunnan Province, March 15, 2016. Tens of thousands of black-headed gulls fly to Kunming from northern China every winter in the past 32 years. (Xinhua/Lin Yiguang)