Resource-dependent weather effect in the reproduction of the White Stork Ciconia ciconia

TLDR: More effective heat conservation in larger broods, and thus lower chick mortality during cold weather, could be the underlying mechanism for the different response to weather in the two populations.

Abstract: Weather affects the breeding success of White Stork Ciconia ciconia, but the effect has not been studied in the context of different food resources or habitat quality. The aim of this study was to determine whether the impact of weather conditions on breeding success was dependent on habitat quality The effect of weather on reproduction was analysed in two populations that differed significantly in the availability of suitable feeding habitats. Multiple regression analyses revealed that of the weather variables analysed (average temperature and rainfall in April, May and June), rainfall in May and temperature in June explained a significant part of the variation in numbers of fledged chicks per pair, but only in the population with poorer food resources. The lack of weather influence in the population with richer food resources was tentatively explained by the larger brood sizes. More effective heat conservation in larger broods, and thus lower chick mortality during cold weather, could be the underlying mechanism for the different response to weather in the two populations.