A waterbird survey in 13 cities in Sichuan province on Jan 6 spotted 78,593 waterbirds belonging to 74 species, including 43 scaly-sided mergansers, a critically endangered duck.

"The survey recorded the largest number of scaly-sided mergansers since it began in 2017," said Que Pinjia, an ornithologist with the Chengdu Research Base of Giant Panda Breeding and the Sichuan Key Laboratory of Conservation Biology for Endangered Wildlife, who is the technical adviser to the annual survey. "The second-highest count was 14 birds, recorded last year."

Que, who took part in the survey in the city of Ziyang, said it aims to understand the species composition, population size and distribution status of waterbirds wintering in the Sichuan Basin and to protect migratory birds and their migration routes.

A total of 337 volunteers from home and abroad took part in the survey, which was originally launched by the Chengdu Bird-watching Society and the Chengdu Research Base of Giant Panda Breeding. Its scope has gradually expanded from the Chengdu Plain to most areas in the Sichuan Basin, Que said.

"This year, for the first time, we managed to cover all major rivers in the basin, including the Yangtze River and its tributaries such as the Minjiang, Tuojiang, Fujiang, Jialing, Qingyi and Dadu," he said.

As a result, the name of the survey was changed from the Chengdu Plain Wintering Waterbirds Census to the Sichuan Basin Wintering Waterbirds Census.

From 8 am to 7 pm on Jan 6, the volunteers from bird-watching organizations, nature education institutions, research institutes, universities, forestry departments and other organizations went to 81 survey spots in 47 districts and counties in the 13 cities to conduct the survey.

Compared with the results of last year's survey, the populations of waterbirds fluctuated in different cities, with a total decrease of about 10,000 birds.

"We speculate that the warmer winter climate this year may have caused some waterbirds to winter in more northern regions," Que said. "We have to wait for the survey results from other areas in the country to analyze the specific reasons."

The five most abundant waterbird species recorded in the survey were the mallard with 9,960 birds, the Eurasian coot with 9,472 birds, the spot-billed duck with 6,591 birds, the black-headed gull with 5,121 birds, and the gadwall with 4,855 birds.

Of the 74 species recorded, one less than last year, five were spotted for the first time in the survey. Four of them — the black-necked crane, the Dalmatian pelican, the Oriental white stork and the glossy ibis — are under first-level State protection.

The other new bird was the gray-headed lapwing.

"The surveys since 2017 have recorded a total of 94 waterbird species," Que said. "That accounts for nearly 56 percent of the waterbirds distributed in Sichuan province."