Data from: Responses in the breeding parameters of the collared flycatcher to the changing climate

Global climate change involves various aspects of climate, including precipitation changes and declining surface wind speeds, but studies investigating biological responses have often focused on the impacts of rising temperatures. Additionally, related long-term studies on bird reproduction tend to focus on breeding onset, even though other aspects of breeding could also be sensitive to the diverse weather aspects. In this study, we aimed to explore how multiple aspects of breeding (e.g. breeding onset, hatching delay, breeding season length, clutch size) were associated with different weather components. We used an almost four-decade-long dataset to investigate the different aspects of breeding parameters of a collared flycatcher (<i>Ficedula albicollis</i>) population in the Carpathian Basin. Analyses revealed some considerable associations, for example, breeding seasons lengthened with the amount of daily precipitation, and clutch size increased with the number of cool days. Parallel or opposing changes in the correlated pairs of breeding and weather parameters were also observed. The phenological mismatch between prey availability and breeding time has notably increased in the last decade. Our results highlight the intricate interplay between climate change and the reproductive patterns of migratory birds, emphasizing the need for a holistic approach. They also underscore the potential threats posed by climate change to bird populations and the importance of adaptive responses to changing environmental conditions.