A group of people find the essence of life in watching but not disturbing the birds, Peng Yining reports in Beijing.

As an icy nightfall wind whipped across Miyun reservoir, a White-naped Crane raised its wings with a lazy flap, almost like a yawn, before rising into the air. Five hundred meters away, 20 bird watchers shivered in the bushes as they attempted to capture the bird's exotic dance through cameras and binoculars. More than 500 of the birds had alighted by the reservoir, 90 kilometers northeast of Beijing's urban area, pecking, preening and shaking their tail feathers.

The cranes, on their annual odyssey that ends as far north as the tundra in southern Siberia, had already flown 2,000 km from southeastern China. At Miyun, they found an oasis on the edge of the industrialized capital where they can gorge themselves on the abundant remains of a cornfield to gain weight, in anticipation of the thousands of kilometers still ahead of them.

"Look! They're about to take off," shouted one birder, prompting his fellow enthusiasts to raise their binoculars as one.

About 5,000 of these birds remain in the wild. Fu Jianping, director of the Beijing Birding Watching Society, or BBWS, founded in 2004, said she is happy that the suburban wetland has become a temporary habitat for the graceful cranes. Last year, she counted around 700 around the reservoir.

To collate data about wetland birds in Beijing, Fu writes down the names, behavior and number of birds she spots on her weekly bird watching trips. On March 23, Fu and her group saw more than 50 types, including White Spoonbills, Hoopoes, and Chinese Grey Shrike. The information collected on these trips is fed into a database founded by the society which helps monitor changes in the environment.

"Birds are one of the primary indicators of the health of the natural environment," Fu said. "By watching and learning about them, the watchers fit into the larger conversation about environmental protection and good stewardship."