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.

"During the daily observation of the Chinese mergansers along the Toudao River on May 17, our staff members saw a mother leading her newborn chicks to jump from the nest on the tree to the ground," said Cui Xiucheng, a veterinarian of the station. "Seven baby birds and another three unhatched duck eggs were found — two in the nest and one on the ground."

The workers took the three eggs back to the rescue station for artificial incubation. On the way, they kept the eggs warm by placing them inside their clothing. "The temperature needs for the incubation of the Chinese merganser are quite high," Cui said. "We made several incubation attempts in past years, but were unsuccessful."

Cui put the three eggs in an incubator consisting of a styrofoam box, an electric hot plate and an instrument used to control the temperature. "I developed the incubator about a year ago and tried to incubate at different temperatures," he said. "This time, I set the temperature at 38.2 C."

He also put a hot water bottle in the box to help maintain the ideal temperature.

"Every four hours, we would turn the eggs to ensure that the heat could penetrate evenly," he said. "We also sprayed warm water twice every 24 hours on the eggshells to keep them moist."

Ten days later, a Chinese merganser and a mallard finally hatched on the early morning of May 27, the latter of which hatched from the egg found on the ground.