A black-tailed gull stands on the coastal mudflats of Haiyan in Jiaxing. [Photo/Tide News]

The black-tailed gulls recently appeared along the coastal mudflats of Haiyan county, Jiaxing, East China's Zhejiang province, capturing the interest of photographers and birdwatchers. 

Black-tailed gulls are medium-sized seabirds, measuring 45 to 51 centimeters in length. They are distinguished by their white head and underparts, grayish back and wings, and a broad black band at the tip of the tail. They typically inhabit coastal islands, reefs, and beaches and are native to China, Japan, and South Korea, and migratory in countries like the United States and Australia.

Local birdwatcher Gu Yueliang spotted them for the first time in eight years of observing Haiyan's birdlife. The sighting of black-tailed gulls in Haiyan demonstrates how far the local ecosystem has improved, he said.

Situated on the northern coast of Hangzhou Bay, Haiyan's coastal mudflats are vital stopover and wintering grounds along major global migratory routes. Each year, over 162 species and 150,000 Eurasian migratory birds pass through. With ongoing restoration projects, the area now supports 344 bird species and 1,796 species of local flora and fauna.

To protect this biodiversity, Haiyan has launched a joint ecological patrol system and established the province's first dedicated station of ecological law enforcement for migratory birds, dismantling bird nets, and rescuing protected species.