People watch gulls on the Dianchi Lake in Kunming, southwest China's Yunnan Province, Dec. 18, 2019. Lots of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Lin Yiguang)

People watch gulls on the Dianchi Lake in Kunming, southwest China's Yunnan Province, Dec. 18, 2019. Lots of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Lin Yiguang)

People watch gulls on the Dianchi Lake in Kunming, southwest China's Yunnan Province, Dec. 18, 2019. Lots of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Lin Yiguang)

A gull flies to eat the food people threw at the Haigeng Dam in Kunming, southwest China's Yunnan Province, Dec. 18, 2019. Lots of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Hu Chao)

A woman feeds a gull at the Haigeng Dam in Kunming, southwest China's Yunnan Province, Dec. 18, 2019. Lots of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Hu Chao)

A girl feeds a gull at the Haigeng Dam in Kunming, southwest China's Yunnan Province, Dec. 18, 2019. Lots of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Hu Chao)

A girl feeds a gull at the Haigeng Dam in Kunming, southwest China's Yunnan Province, Dec. 18, 2019. Lots of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Hu Chao)

A visitor feeds a gull at the Haigeng Dam in Kunming, southwest China's Yunnan Province, Dec. 18, 2019. Lots of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Hu Chao)

A visitor feeds a gull at the Haigeng Dam in Kunming, southwest China's Yunnan Province, Dec. 18, 2019. Lots of gulls migrate to Kunming for the warm weather there in the winter. (Xinhua/Hu Chao)