A kingfisher perches on a mangrove tree at Sanjiang mangrove wetland park in Haikou, south China's Hainan Province, on Dec. 23, 2020. The Dongzhaigang wetland ecological rehabilitation project was accomplished recently, according to the Dongzhaigang National Nature Reserve Authority in Haikou. Kicked off on March 18, 2019, the project aimed to effectively rehabilitate the ecological systems including mangrove forests along the seashore of Dongzhaigang so that migrant birds in the country may find better habitats in winter time. (Xinhua/Yang Guanyu)

A kingfisher perches beside a mangrove forest at Sanjiang mangrove wetland park in Haikou, south China's Hainan Province, on Dec. 23, 2020. The Dongzhaigang wetland ecological rehabilitation project was accomplished recently, according to the Dongzhaigang National Nature Reserve Authority in Haikou. Kicked off on March 18, 2019, the project aimed to effectively rehabilitate the ecological systems including mangrove forests along the seashore of Dongzhaigang so that migrant birds in the country may find better habitats in winter time. (Xinhua/Yang Guanyu)

Aerial photo taken on Dec. 23, 2020 shows newly planted mangrove trees at Sanjiang mangrove wetland park in Haikou, south China's Hainan Province. The Dongzhaigang wetland ecological rehabilitation project was accomplished recently, according to the Dongzhaigang National Nature Reserve Authority in Haikou. Kicked off on March 18, 2019, the project aimed to effectively rehabilitate the ecological systems including mangrove forests along the seashore of Dongzhaigang so that migrant birds in the country may find better habitats in winter time. (Xinhua/Yang Guanyu)

Herons fly over newly planted mangrove trees at Sanjiang mangrove wetland park in Haikou, south China's Hainan Province, on Dec. 23, 2020. The Dongzhaigang wetland ecological rehabilitation project was accomplished recently, according to the Dongzhaigang National Nature Reserve Authority in Haikou. Kicked off on March 18, 2019, the project aimed to effectively rehabilitate the ecological systems including mangrove forests along the seashore of Dongzhaigang so that migrant birds in the country may find better habitats in winter time. (Xinhua/Yang Guanyu)

A kingfisher perches on a mangrove tree at Sanjiang mangrove wetland park in Haikou, south China's Hainan Province, on Dec. 23, 2020. The Dongzhaigang wetland ecological rehabilitation project was accomplished recently, according to the Dongzhaigang National Nature Reserve Authority in Haikou. Kicked off on March 18, 2019, the project aimed to effectively rehabilitate the ecological systems including mangrove forests along the seashore of Dongzhaigang so that migrant birds in the country may find better habitats in winter time. (Xinhua/Yang Guanyu)

Aerial photo taken on Dec. 23, 2020 shows newly planted mangrove trees at Sanjiang mangrove wetland park in Haikou, south China's Hainan Province. The Dongzhaigang wetland ecological rehabilitation project was accomplished recently, according to the Dongzhaigang National Nature Reserve Authority in Haikou. Kicked off on March 18, 2019, the project aimed to effectively rehabilitate the ecological systems including mangrove forests along the seashore of Dongzhaigang so that migrant birds in the country may find better habitats in winter time. (Xinhua/Yang Guanyu)

A kingfisher perches beside a mangrove forest at Sanjiang mangrove wetland park in Haikou, south China's Hainan Province, on Dec. 23, 2020. The Dongzhaigang wetland ecological rehabilitation project was accomplished recently, according to the Dongzhaigang National Nature Reserve Authority in Haikou. Kicked off on March 18, 2019, the project aimed to effectively rehabilitate the ecological systems including mangrove forests along the seashore of Dongzhaigang so that migrant birds in the country may find better habitats in winter time. (Xinhua/Yang Guanyu)

Aerial photo taken on Dec. 23, 2020 shows newly planted mangrove trees at Sanjiang mangrove wetland park in Haikou, south China's Hainan Province. The Dongzhaigang wetland ecological rehabilitation project was accomplished recently, according to the Dongzhaigang National Nature Reserve Authority in Haikou. Kicked off on March 18, 2019, the project aimed to effectively rehabilitate the ecological systems including mangrove forests along the seashore of Dongzhaigang so that migrant birds in the country may find better habitats in winter time. (Xinhua/Yang Guanyu)