Herons rest on a tree at a wetland in Fengnan District in Tangshan, north China's Hebei Province, June 19, 2020. In recent years, the improving environment in Fengnan has attracted more and more birds including herons to inhabit at the wetland. (Xinhua/Yang Shiyao)

Aerial photo shows herons resting on trees at a wetland in Fengnan District in Tangshan, north China's Hebei Province, June 19, 2020. In recent years, the improving environment in Fengnan has attracted more and more birds including herons to inhabit at the wetland. (Xinhua/Yang Shiyao)

New born herons are seen at the nest at a wetland in Fengnan District in Tangshan, north China's Hebei Province, June 19, 2020. In recent years, the improving environment in Fengnan has attracted more and more birds including herons to inhabit at the wetland. (Xinhua/Yang Shiyao)

Herons rest on a tree at a wetland in Fengnan District in Tangshan, north China's Hebei Province, June 19, 2020. In recent years, the improving environment in Fengnan has attracted more and more birds including herons to inhabit at the wetland. (Xinhua/Yang Shiyao)

Herons rest on trees at a wetland in Fengnan District in Tangshan, north China's Hebei Province, June 19, 2020. In recent years, the improving environment in Fengnan has attracted more and more birds including herons to inhabit at the wetland. (Xinhua/Yang Shiyao)