Local weather differently affects collared flycatcher reproduction at different altitudes

Abstract

Abstract Temperature and precipitation are amongst the most important characteristics of local climatic conditions affecting the breeding biology of birds. Many bird species experiencing higher temperatures lay their eggs earlier and/or have bigger clutches. Higher precipitation can lead to a decrease in food availability and/or an increase of the costs of thermoregulation, which consequently may result in lower breeding success. In this paper we present differences in the breeding biology of two collared flycatcher (Ficedula albicollis) populations experiencing different temperatures and precipitation conditions associated with the different altitudes of their localities. We found differences in clutch size and nest success, as well as small differences in dates of egg laying. The population breeding at a higher altitude, and thus harsher conditions, was characterized by smaller clutches and lower nest success. In addition, this population was significantly affected by local weather, and showed correlation between both the beginning of egg laying and the local temperature, as well as between nest success and precipitation. Conversely, the population inhabiting the lower elevation locality with milder conditions showed no relationships with temperature or precipitation. These results suggest that severe conditions, such as high altitude, enhance the effect of local climatic conditions on collared flycatcher breeding ecology.