Volunteers band crested tern chicks on the Jiushan Islands in Xiangshan county, Ningbo from July 10 to 11. [Photo/zjol.con.cn]

More than 30 volunteers spent two days banding 198 crested tern chicks on the Jiushan Islands in Ningbo's Xiangshan county, East China's Zhejiang province from July 10 to 11.

"Bird banding is an efficient way to study the movement and behavior of wild birds," said Fan Zhongyong, a researcher at Zhejiang Museum of Natural History, "The metal ring banded on the left foot of each bird is used as that bird's global identification card, while the green plastic ring on the right foot makes the bird easily spotted when carrying out onsite observations.”

The Chinese crested tern is classed as "critically endangered" on the International Union for Conservation of Nature (IUCN) Red list. The bird's breeding season lasts from April to August.  

The Xiangshan Jiushan Islands National Nature Reserve is the largest breeding site for Chinese crested terns in the world.

According to data from the nature reserve, a total of 115 Chinese crested terns have hatched and more than 1,200 Chinese crested tern chicks have been banded on the islands since 2015.