Effects of Variable Responses to Climate Change on the Interactions of Migratory and Resident Birds in Europe

Abstract

Long-distance migrants and residents may respond to large-scale climate change by advancing egg laying dates. It is expected that variation in changes in avian laying dates among similar species affects their interactions in an ecological community. By analyzing long-term trends of the mean laying dates (MLD) of pied flycatcher Ficedula hypoleuca, collared flycatcher Ficedula albicollis, and great tits Parus major across 25 study sites in Europe from five published studies, the paper uses two-tailed t tests to show that variable adjustments in laying dates in different species have different implications on their interactions across Europe. It is found that pied flycatcher advanced laying dates significantly faster compared to great tits in Central Europe, gaining advantage in their competition for nest holes. Additionally, the study shows that pied flycatcher and collared flycatcher potentially share smaller overlap in laying dates in their sympatric breeding ground in Northern Europe, which may decrease the occurrences of hybridization, whereas the trend reverses in Central Europe. The results highlight that geographical variations in phenological responses to climate change have complicated effects on interspecific interaction, a novel research field that lacks empirical results. The conclusions of this study provide potential directions for empirical studies of climate change in the future.