As winter approaches, flocks of swans from Mongolia and Siberia migrate thousands of miles to Central China's Henan province before cold currents sweep over North China.
The shoal wetland spanning more than 26,000 hectares on the banks of the Yellow River in the city of Sanmenxia is their destination for wintering.
"The first batch of around 30 swans arrived in late October, with many more still to come," said Gao Ruyi, head of the bird ringing station of the city's swan wetland protection center.
Located in a bird migration area in Central China, Sanmenxia, home to a population of 2 million residents, has adopted a series of ecological protection measures, such as a sewage water discharge ban and wetland restoration, to provide a better habitat for the wintering birds, including swans.
The nature reserve of the wetland disinfected the swans' habitat in early October, before hundreds of volunteers joined the staff from the forestry and public security departments for patrolling and monitoring in mid-October. Later in the same month, vehicles were banned from running on the roads near the wetland to ensure a tranquil and safe environment for the feathered visitors. The traffic ban will last until early March when swans will head northward.
Zhang Mingyun, head of the city's volunteer association for swan protection, patrols around the wetland almost every day during the swans' stay there. He observes the swans' behaviors, takes photographs and spreads knowledge regarding their protection among other residents.
"Being our city bird, the swan is just like our own child. Locals have a special bond with swans," Zhang said, adding that the swan "guardians" like him would submit suggestions to relevant government departments for swan protection every year based on their latest observations.
With the joint efforts of residents and relevant departments, Sanmenxia issued the country's first local regulation on the protection of swans in 2017, and set Nov 22 every year as "White Swans' Day."
Statistics show the wild bird species in the wetland of Sanmenxia rose to 315 from 175 over the past two decades. In 2022, more than 16,000 swans wintered in Sanmenxia, accounting for more than half of the country's total.
Li Changkan, an ornithologist at the Zhengzhou Normal University, said birds are a "barometer" for the wetland ecology. A sound climate, safe environment and abundant food supplies are important for wintering birds.
"The government's legislative protection and residents' awareness of bird protection have created a safe habitat for birds," said Li.