Black-headed gulls fly as a boat passes by in Kunming, capital of southwest China's Yunnan Province, Dec. 2, 2011. As winter falls, tens of thousands of black-headed gulls migrated from Siberia to Kunming for warmer weather. (Xinhua/Qin Qing)
Black-headed gulls fly as a boat passes by in Kunming, capital of southwest China's Yunnan Province, Dec. 2, 2011. As winter falls, tens of thousands of black-headed gulls migrated from Siberia to Kunming for warmer weather. (Xinhua/Qin Qing)