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 eco-evolutionary 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.

Automated summary

Urbanization is a rapid global environmental change that presents new selection pressures for wildlife. The study found that urban blackbirds adapted to the urban environment by adopting shorter and more frequent incubation strategies, while rural blackbirds preferred longer and fewer bouts. Urban areas were characterized by warmer ambient temperatures and lower predation pressures, and urban blackbirds had greater behavioral plasticity and a wider range of egg temperatures. The survival and hatching rates of urban blackbirds were higher than those of rural blackbirds, highlighting the importance of behavioral adaptation in the colonization of new environments.