Behavioral rhythms and time budgets are influenced by a number of factors, including temperature, weather, and gender. Animals often adopt different survival strategies in different environments and knowledge of these strategies can benefit the conservation and management of a species. The Chinese merganser (Mergus squamatus) is listed as an endangered species by the International Union for Conservation of Nature. Given the poor status of the species, it is important to understand the factors affecting their survival. To address this, we evaluated the effects of temperature and gender on survival strategies during the wintering period. We observed the behaviors of Chinese Merganser in Wuyuan County, Jiangxi Province, China, during the wintering season between 13 November 2011 and 13 March 2012. We documented the behavior of individual birds using an instantaneous scanning sampling method.The main behaviors included feeding, resting, swimming, and maintenance. We used an independent sample t-test to analyze for differences in the behavioral time budget between males and females. There was a significant difference between the sexes in social behavior (P<0.05), but not other behaviors (P >0.05). This is because: (1) both males and females are focused on maintaining adequate energy supply to survive during the non-breeding period and (2) there is little difference in the body size of males and females. We observed a clear rhythm in feeding and resting behaviors of both males and females (one-way ANOVA, P<0.05), but not for the remaining behaviors (P >0.05). The air temperature had a significant influence on wintering behavior in the Chinese merganser. The time spent feeding was significantly shorter in months where the average temperature was <10℃ month compared to months when the average temperature was >10℃ (P<0.05). In contrast, the reverse was true for swimming behavior (P >0.05). Thus, our data suggest that Chinese mergansers minimize energy consumption in cold weather by decreasing activity levels, a strategy to cope with decreased food intake. We observed differences in daily behavioral rhythms between months and behavior types. In the months in which the average temperature was >10℃ we observed a rhythm in vigilance behavior (P<0.05), but not the remaining behaviors (P >0.05). In months in which the average temperature was >10℃ we observed a rhythm in feeding and resting behaviors (P<0.05), but not in the remaining behavior types (P >0.05). Thus, our results suggest that changes in temperature are associated with changes in the daily behavioral rhythms of Chinese mergansers. Low temperatures likely increase energy expenditure during the night, resulting in individuals dedicating more time to feeding in the morning to supplement energy. In >10℃ months, there were two minor peaks in resting behavior: at midday and in the evening. However, in <10℃ months the frequency of resting behaviors remained high between 11:00 and 18:00 (except 13:00-13:59). We hypothesize that the Chinese merganser adopted this strategy because the temperatures were low in the afternoon and evening in <10℃ months, resulting in the birds increasing the frequency of resting behaviors to minimize energy consumption during this period. Taken together, our results suggest that this species reduces activity levels to decrease energy consumption and heat loss in low-temperature environments.