"We had taken some experienced bird lovers to faraway provinces and even abroad, before the pandemic forced such activities to stop," he says.

A group of 10 birders joined a beginners' session at Century Park in Pudong on a recent trip. Led by Zheng Yihui, an avian ecologist, the group consisting mainly of parents with schoolchildren walked around the park with binoculars and a chart of the birds frequently found in the area. Zheng stopped every now and then, pointing at birds perched on the branches of trees, or swimming in the pond. Often he took pictures of the birds with his telephoto lens, and showed the details in the images on the viewing screen on his camera.