Winter Ecology and Conservation Threats of Scaly-sided Merganser Mergus squamatus in Poyang Lake Watershed, China

First multiple surveys were conducted along eight river sections within the Poyang Lake watershed, Jiangxi Province, China, to examine winter ecology of the scaly-sided or Chinese Merganser (Mergus squamatus) and to assess threats to its conservation. Transect lines and point counts were combined to estimate the population size of the scaly-sided Merganser during the period November 2010 to March 2011. Along all eight surveyed river sections in four rivers, the riparian environment was mountain forest or close to mountain forest on one or both sides of the rivers. The scaly-sided Merganser was often found in the rivers with scattered shoals. The largest number of scaly-sided Mergansers seen during each of the five months varied from 61 to 91. Groups of Chinese Merganser were classified as male, female, mixed sex, solitary female and solitary male. Mixed sex groups were the most frequently encountered (64 sightings) and comprised 71.91% of all groups sighted (89 groups). Solitary mergansers accounted for 22.47% (male, 15.73%; female, 6.74%) of all sightings and were also frequently encountered. Solitary Merganser and groups with 2-9 individuals account for 22.47% and 64.04% of total group number (n=89). Feeding, swimming, resting and maintenance were the most frequent behavior patterns. For the first time, mergansers were observed copulating in winter in the Wuyuan River section. The sex ratio was 1:0.74 (Females + sub-adults: males, n=432). Threats to the conservation of the scaly-sided Mergansers included sand mining, fishing, riparian vegetation destruction and water pollution. Taiyangsheng, Taopi, Qinghu and Wuyuan sections should be prioritized for protection because these areas have relatively large and stable population. We recommend specific conservation strategies designed to protect this endangered species.