A white-throated kingfisher is seen in Wuyuan River National Wetland Park in Haikou, south China's Hainan Province, March 30, 2022. Haikou was accredited by the Ramsar Convention as an international wetland city in 2018. The wetland coverage rate of the city is about 12.7 percent. Photo:Xinhua

This aerial photo taken on Nov 15, 2022 shows the scenery of Dongzhaigang National Nature Reserve in Haikou, south China's Hainan Province. Haikou was accredited by the Ramsar Convention as an international wetland city in 2018. The wetland coverage rate of the city is about 12.7 percent. Photo:Xinhua

Blue-tailed bee-eaters are seen in Wuyuan River National Wetland Park in Haikou, south China's Hainan Province, April 15, 2022. Haikou was accredited by the Ramsar Convention as an international wetland city in 2018. The wetland coverage rate of the city is about 12.7 percent. Photo:Xinhua

This aerial photo taken on Nov 15, 2022 shows the scenery of the wetland of Maiya River in Haikou, south China's Hainan Province. Haikou was accredited by the Ramsar Convention as an international wetland city in 2018. The wetland coverage rate of the city is about 12.7 percent. Photo:Xinhua

Blue-tailed bee-eaters are seen in Wuyuan River National Wetland Park in Haikou, south China's Hainan Province, April 15, 2022. Haikou was accredited by the Ramsar Convention as an international wetland city in 2018. The wetland coverage rate of the city is about 12.7 percent. Photo:Xinhua

Herons fly over the Dongzhaigang National Nature Reserve in Haikou, south China's Hainan Province, Jan 28, 2022. Haikou was accredited by the Ramsar Convention as an international wetland city in 2018. The wetland coverage rate of the city is about 12.7 percent. Photo:Xinhua

Herons rest in the Dongzhaigang National Nature Reserve in Haikou, south China's Hainan Province, Jan 28, 2022. Haikou was accredited by the Ramsar Convention as an international wetland city in 2018. The wetland coverage rate of the city is about 12.7 percent. Photo:Xinhua