Wild swans are seen at a wetland in Pinglu, north China's Shanxi Province, Oct. 31, 2018. Migratory wild swans recently came to the wetland to spend the winter. (Xinhua/Zhan Yan)
Wild swans are seen at a wetland in Pinglu, north China's Shanxi Province, Oct. 31, 2018. Migratory wild swans recently came to the wetland to spend the winter. (Xinhua/Zhan Yan)
Wild swans are seen at a wetland in Pinglu, north China's Shanxi Province, Oct. 31, 2018. Migratory wild swans recently came to the wetland to spend the winter. (Xinhua/Zhan Yan)
Wild swans are seen at a wetland in Pinglu, north China's Shanxi Province, Oct. 31, 2018. Migratory wild swans recently came to the wetland to spend the winter. (Xinhua/Zhan Yan)
Wild swans are seen at a wetland in Pinglu, north China's Shanxi Province, Oct. 30, 2018. Migratory wild swans recently came to the wetland to spend the winter. (Xinhua/Yang Chenguang)
Wild swans are seen at a wetland in Pinglu, north China's Shanxi Province, Oct. 30, 2018. Migratory wild swans recently came to the wetland to spend the winter. (Xinhua/Yang Chenguang)
Wild swans are seen at a wetland in Pinglu, north China's Shanxi Province, Oct. 31, 2018. Migratory wild swans recently came to the wetland to spend the winter. (Xinhua/Yang Chenguang)
A wild swan is seen at a wetland in Pinglu, north China's Shanxi Province, Oct. 31, 2018. Migratory wild swans recently came to the wetland to spend the winter. (Xinhua/Yang Chenguang)