In the spring of 2020, the number of black storks in Beijing rose to about 100, and their habitats expanded from Fangshan to Haidian, Daxing, Shunyi and Pinggu districts, the bureau said.

Li, who established a program to protect black storks along the river in 2000, said he has witnessed the increase from just a few black storks to more than 70 in the region, and sees the black stork as a token of biodiversity in Beijing.

From April to June every year black storks lay eggs and hatch them by the river. Li said he and his co-workers have the task of watching out for the birds' nests and preventing tourists from scaring or hurting them, such as by lighting fireworks.

Troublemaker animals

Yet local people may not be especially fond of black storks at first. Li recalled that a fish farmer asked for his help sometime before 2008 because the birds kept preying on his fancy carp, even though he lit firecrackers in an attempt to drive them away.

Li told him to increase the height of the fish pool's brick walls and get the level of water in it to rise to at least 80 centimeters. He did, and stopped losing his fish to the birds.

Li and his team also spend a lot of time on preventing other wild animals, such as vultures and boars, from wrecking livestock and crop plants.

Every year migrating vultures come to stay in mountains on the outskirts of Beijing for two months around Spring Festival and attack local people's goats.