About 4,000 migratory birds will be fitted with electronic loop on their feet this year so researchers at the Chongming East Coast Nature Preserve can study them.
So far, 22 species of migratory wading birds have been marked with the loops.
"Chongming nature preserve is China's first center to let migratory birds carry loops," according to Tang Chendong, an engineer of the preserve. "In this way, we can study the flying routes and living habits of the birds."
Since the preserve was set up in 1998, researchers have caught birds every April and September and fit them with coded loops. The information on the loops can be read by researchers worldwide.
Altogether 23 birds wearing such loops were found this spring, with 22 getting the loops in Australia and one getting the loop in Chongming.
The information recorded by the preserve showed it took a migratory bird only seven days to travel from Australia to China's east coast.