Mute swans and pied avocets were seen in Ulansu Lake, Inner Mongolia autonomous region, on Monday.

More than 1,200 mute swans are spotted in the lake every year, nearly half the total population of the species in China, which is less than 3,000.

Ulansu Lake covers an area of 300 square kilometers and has functions of flood prevention, waterflow balance, biodiversity and improving the climate in Yellow River region. The area is also home to more than 260 categories of birds and more than 20 categories of fish.

Tang Ziye contributed to the story.