Shallow sub-lakes are essential for sustaining the successful wintering of waterbirds in Poyang Lake,China

For migratory waterbirds,the quality of wintering habitat is related to spring migration and successful breeding in the next year.The availability of food resources in the habitat is critical and varies within water levels.Although the water-level fluctuations in Poyang Lake have been extremely variable interannually in recent years,the wintering waterbird populations have remained relatively stable.Hence,the mechanism of maintaining the stability is worth exploring.This study aimed to compare the distribution of vegetation and herbivorous wa-terbirds in 2015-2016 and 2016-2017,focusing on three shallow sub-lakes and one main lake are.The results showed that the emergence of tubers and the growth of Carex spp.provided a continuous food supply and habitat for wintering waterbirds with a gradual decline in the water level.Shallow sub-lakes supported almost all of the tuber-eating waterbirds(1.42-1.62×10^(5))and most geese(1.34-1.53×10^(6)).However,the main lake area,covered with Persicaria hydropiper,did not provide adequate and accessible food.This resulted in almost no distribution of tuber-eating waterbirds,with only a few geese congregating in early winter.Our results demonstrated that the shallow sub-lakes under human control provided a different environment from the main lake and are key to sustaining the successful wintering of hundreds of thousands of migratory waterbirds in Poyang Lake.Therefore,we recommend refining the anthropogenic management of the shallow sub-lakes to regulate the water level to ensure the carrying capacity of Poyang Lake.

A highly effective incubation strategy enhanced the urban bird hatch success

Urbanization is currently considered one of the most rapid types of global environmental change.Urban habitats are biotically and abiotically different from their rural areas,i.e.,the ambient temperature,predator,and food availability.These novel challenges create new selection pressures,which allow one to investigate ecoevolutionary responses to contemporary environmental change.A total of 118 breeding nests were monitored for nest predation in both urban and rural areas from 2018 to 2020.We used environmental factors from urban and rural areas and behavioral data from 439 Chinese Blackbird(Turdus mandarinus)valid incubation days to understand the impact of urbanization on the incubation behavior of blackbirds and its adaptation mechanism to the urban environment.Cities have warmer ambient temperatures and lower predation pressures than rural areas.Urban blackbirds chose the incubation strategy with shorter and more bouts,while rural blackbirds selected the incubation strategy with longer and fewer bouts.The plasticity of incubation behavior of urban blackbirds was higher than that of rural areas,and the range of egg temperature was also higher than that of rural areas.In addition,incubation temperature and the number of bouts per day were the key factors affecting the day survival rate of blackbirds,and the hatching rate of urban blackbirds was higher than that of rural blackbirds.Our results provide evidence for behavioral shifts in blackbirds during adaptation to urbanization and support the central role of behavioral adaptation in the successful colonization of new environments by wildlife.These help us understand the behavioral characteristics required for wildlife to live in cities and the urban adaptors faced environmental pressures.