Wild Duck Lake National Wetland Park in suburban Beijing's Yanqing district is an essential stopover for migrating birds on the East Asia-Australasian Flyway. [Photo provided to China Daily]

"My rich experience also helps my judgment. I know about birds' appearances and habitats."

He's familiar with the specs of more than 200 avians but always carries a copy of A Field Guide to the Birds of China in case he encounters a bird that may be a species unknown to exist in the area.

The park isn't only important to birds endemic to North China but also serves as an essential stopover on the East Asia-Australasian Flyway.

Beijing's largest wetland reserve's biodiversity has increased since authorities restored more than 1,300 hectares over the past decade.