A visitor feeds a gull at the Haigeng Dam in Kunming, southwest China's Yunnan Province, Dec. 15, 2020. Tens of thousands of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Wang Guansen)

People watch and feed gulls at the Haigeng Dam in Kunming, southwest China's Yunnan Province, Dec. 15, 2020. Tens of thousands of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Wang Guansen)

Aerial photo taken on Dec. 15, 2020 shows gulls at the Haigeng Dam in Kunming, southwest China's Yunnan Province. Tens of thousands of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Wang Guansen)