Swans rest in the bay at Yandunjiao Village in Rongcheng City, east China's Shandong Province, Jan. 23, 2019. Around 1,000 swans fly from Siberia to the Yandunjiao bay to spend winter each year, with the establishment of the Rongcheng state-level swan nature reserve and the increased public awareness of protection of swans. (Xinhua/Zhu Zheng)

Swans rest in the bay at Yandunjiao Village in Rongcheng City, east China's Shandong Province, Jan. 23, 2019. Around 1,000 swans fly from Siberia to the Yandunjiao bay to spend winter each year, with the establishment of the Rongcheng state-level swan nature reserve and the increased public awareness of protection of swans. (Xinhua/Zhu Zheng)

Swans rest in the bay at Yandunjiao Village in Rongcheng City, east China's Shandong Province, Jan. 23, 2019. Around 1,000 swans fly from Siberia to the Yandunjiao bay to spend winter each year, with the establishment of the Rongcheng state-level swan nature reserve and the increased public awareness of protection of swans. (Xinhua/Zhu Zheng)

Swans are seen in the bay at Yandunjiao Village in Rongcheng City, east China's Shandong Province, Jan. 23, 2019. Around 1,000 swans fly from Siberia to the Yandunjiao bay to spend winter each year, with the establishment of the Rongcheng state-level swan nature reserve and the increased public awareness of protection of swans. (Xinhua/Zhu Zheng)

Swans rest in the bay at Yandunjiao Village in Rongcheng City, east China's Shandong Province, Jan. 23, 2019. Around 1,000 swans fly from Siberia to the Yandunjiao bay to spend winter each year, with the establishment of the Rongcheng state-level swan nature reserve and the increased public awareness of protection of swans. (Xinhua/Zhu Zheng)

Swans perch in the bay at Yandunjiao Village in Rongcheng City, east China's Shandong Province, Jan. 23, 2019. Around 1,000 swans fly from Siberia to the Yandunjiao bay to spend winter each year, with the establishment of the Rongcheng state-level swan nature reserve and the increased public awareness of protection of swans. (Xinhua/Zhu Zheng)

Swans perch in the bay at Yandunjiao Village in Rongcheng City, east China's Shandong Province, Jan. 23, 2019. Around 1,000 swans fly from Siberia to the Yandunjiao bay to spend winter each year, with the establishment of the Rongcheng state-level swan nature reserve and the increased public awareness of protection of swans. (Xinhua/Zhu Zheng)