A flock of about 150 mandarin ducks is found to be spending the winter in Zhoushan. [Photo/zhoushan.cn]

A flock of about 150 mandarin ducks was discovered to be spending the winter in Zhoushan, East China's Zhejiang province, the largest flock ever found in the city, local media reported on Feb 23.

The ducks are under State protection, according to Chen Bin, senior engineer of Zhoushan's natural resources and planning bureau.

He said that in previous years, smaller flocks of 20 or 30 mandarin ducks would spend the winter in Zhoushan. This year's flock is the largest ever seen in the city.

The increasing number of migratory birds in Zhoushan is believed to be due to the improvement in Zhoushan's natural environment.

Chen noted that Zhoushan has continued making progress in protecting its wildlife and forests in recent years, resulting in a better environment and more food for mandarin ducks.

In addition, the pleasant climate and diverse vegetation in Zhoushan provide a suitable habitat for wild birds, and an increasing number of rare bird species are being found in the city.

"In 2020, two or three rare bird species were discovered in Zhoushan," said Chen, noting that the red-breasted merganser found at the end of December is also exceedingly rare in the province.

Zhoushan is currently home to 245 bird species, including more than 20 species under State protection.

The city is also home to the Wuzhishan Archipelago, a nature reserve for birds that attracts tens of thousands of migrating birds every year. At dusk, the islands' sky is filled with birds, a phenomenon that is known as one of the "four wonders of the East China Sea".