"That's a bird I only saw when I was a child," he said.

He treated the bird like a treasure and regularly patrolled the wetland to provide help in case of need.

"In the winter, the lake was frozen, so I made a big hole in the ice so the swan could look for food," Han said, adding that it safely migrated southward a few months later.

"I am glad that the natural wetland near my home has become a home for such beautiful birds, and I'm more than willing to do my part to promote harmony between humans and nature."

Since then, going to the wetland and caring for the birds has become a regular part of his life.

One Tuesday afternoon, he visited after school to make sure none of the birds was injured and if any new species had arrived.

"I stay for about two hours a day. The area is about 2 square kilometers," Han said. It takes about 10 minutes by motorcycle to make the 6-km journey from his home to the wetland.