Breeding performance of the White-throated Dipper (Cinclus cinclus) under different temperature conditions

Abstract

Many bird species breeding under optimal temperature conditions show higher reproductive success. However, less information can be found about how the reproductive output differs within one population and one breeding season. To find inter and intra-seasonal differences in several aspects of breeding ecology and breeding output we monitored 223 breedings of the White-throated Dippers within the three river basins of northern Slovakia (Central Europe) in 2010–2018. We registered the beginning of egg laying, clutch size, nest success and the proportion of second clutches. There were significant differences in egg-laying commencement between breeding seasons. The mean February and March temperature significantly influenced the first egg day (20 February–18 March), median laying date (8 March–6 April), the interval between the first and the last first egg in all clutches in one breeding season (37–50 days) and the proportion of second clutches (0.77%–0.95%). However, the differences were found not only between different seasons. The egg-laying initiation of individual nests within each season was considerable affected by the altitude and the proportion of second clutches of particular nests was significantly influenced by their timing of egg laying.