A long-term study reveals the impact of weather conditions on avian fitness

Here, we present an analysis based on a 40-year dataset from a nest-box population of the collared flycatcher ( Ficedula albicollis ). Our objective is to examine the impact of weather conditions during the incubation and nestling period on key indicators of individual fitness, including offspring production and local annual recruitment rate. Our findings provide compelling evidence that climatic conditions experienced during both incubation and nestling periods significantly impact the number of fledglings and recruits. Specifically, we observed that higher precipitation during the nestling period negatively affects the number of fledglings and increases brood failure. Interestingly, higher precipitation during the incubation period is linked to increased recruitment numbers. Moreover, we found that warmer weather during both the incubation and nestling periods decreases brood failure, and more importantly, higher temperatures during the nestling period are positively associated with the number of recruits. These results underscore the complex interplay between weather patterns and avian reproductive strategies, highlighting the importance of long-term ecological studies in understanding the impacts of climate change on bird populations. By addressing the variability of climatic influences across different life stages, future research can help develop more comprehensive models for predicting the resilience of avian species in the face of ongoing climate challenges.