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."

In the summer of 2021, he thrice spotted snakes approaching in the surveillance footage and each time without hesitation, he rushed to drive them away, erecting an invisible barrier for the birds.

In early March 2023, Song captured in the surveillance footage a graceful Chinese merganser circling around the tree hollow.

The rare, beautiful duck has existed for over 10 million years, which is why the birds are often referred to as "living fossils with wings".

The species has been on the Red List of Threatened Species of the International Union for Conservation of Nature, and it's also under first-grade State protection in China.

Its presence in a wetland is indicative of the area's ecological health, as the birds require a clean aquatic environment and generally choose to live near unpolluted bodies of water and in nature reserves.

"The past years' experience told me that the precious bird was going to settle here," he said. "However, worries followed amidst the joy. If the Chinese merganser occupied the sole natural nest, where would the mandarin duck family find their shelter?"

A bold idea brewed in his mind to build more homes for the increasing bird families, which also received support from his wife.

He spent over 10,000 yuan ($1,391) from the family's savings building three artificial nests in 2023 and another 18 in 2024, all equipped with monitoring equipment.

So far, the warm artificial bird nests have welcomed 10 pairs of mandarin ducks and four white-cheeked starlings to settle down. The Chinese merganser Song monitored has hatched eggs for three consecutive years.

"The Chinese merganser hatched 10 baby birds in 2023 and 2024, respectively," he said. "It was observed in the Yalu River Basin on March 9 for the first time this year. From March 27 to April 12, it laid 12 eggs in the nest and after 35 days' hatching, all the baby birds emerged from the shells."

As the last baby bird leaped out of the nest and staggered toward the rippling river on May 16, Song could not help shedding tears.

Over the past seven years, he has saved over 100 birds and animals in distress, including 31 mandarin ducklings orphaned due to their mothers' death, 11 mallard ducks, and a Common Kestrel that mistakenly ingested a poisonous insect.

Han Junhong in Changchun contributed to this story.