Since mid-May, Song Menghe has been accustomed to searching for familiar figures — a mother Chinese merganser and her ducklings — while patrolling along the Yalu River in Changbai county, Jilin province.

Song, 55, director of the forestry station in the county's Shierdaogou township, has built 21 artificial nests along the river, helping rare birds, such as Chinese mergansers and mandarin ducks, hatch eggs.

In the spring of 2018, when Song patrolled along the river, he discovered a tree hollow where a pair of mandarin ducks were nesting and hatching.

"It was a very magical experience to find the faint sound of birds breaking out of their shells," he said. "From then on, I paid lots of attention to the hollow while patrolling around it."

In 2021, in order to monitor the hatching process of birds and protect rare birds from being damaged by natural enemies during hatching, Song and his colleagues installed remote monitoring equipment above the tree.

Not long after, Song discovered through monitoring that a mandarin duck mother hatching eggs had not returned to the nest, leaving its seven eggs in the nest.

After much contemplation, he decided to take the mandarin duck eggs home and hatch them using an incubator.

After 22 days of artificial incubation, five mandarin ducklings hatched.

Then the task of raising them became a new challenge.

"Initially, I fed them with millet porridge, egg yolks and pellet feed," he said. "As they grew day by day, their appetites increased. My wife and I had to catch more river shrimp, fish and grasshoppers every day."

Several months later, Song decided to release them back into the wild, but after some attempts, he found that the young mandarin ducks were not yet capable of surviving in the wild. "Therefore I decided to send them to the Jilin Provincial Wildlife Rescue and Breeding Center in Changchun," he said. "I drove over six hours to reach the destination where they could receive better care."