A flock of rare gulls have been spotted nesting at the mouth of the Yangtze River, ornithologists said yesterday.

Seventy-six Saunders' gulls, classified as an endangered species, were seen in the Jiuduansha State Nature Preserve in Pudong when preserve workers sailed into the normally inaccessible Xiasha area on the spring tide.

Before the latest sighting, only single birds had been seen in the preserve, experts said.

"This indicates the environment of Jiuduansha has been much improved under our protection," said Chen Xiuzhi, an officer with the preserve management department.

Chen said the number of birds was nearing the world standard of 85 needed to call the area a habitat for the gulls.

There are only 7,000 to 9,000 Saunders's gulls estimated to be left in the world. Once being considered to be extinct, the bird was spotted on a beach in Yancheng, Jiangsu Province, by a domestic scientist in 1988 and soon was listed as an endangered species.

Yu Weidong, a bird expert from the Shanghai Normal University, said one of the breeding grounds for Saunders' gulls was near the estuary of the Liaohe River based on a study in recent years. The Saunders' gulls found in the city are believed to fly from the Liaohe River to spend the winter in the south and then return in the spring.

Officials with the management department said they would strengthen patrols and supervision in the Xiasha area to guarantee the safety of the gulls.

(Source: www.shanghai.gov.cn )