Effects of climate variables on the White Stork (Ciconia ciconia L.) productivity in a long term study

Abstract We analysed the effects of weather and climatic patterns on the productivity of the White Stork in Hungary between 1958 and 2017, using i) linear mixed effect models (LMM), ii) LMM-s extended by a single random effect variable or a nested combination; iii) LMM-s extended by a single fixed effect variable and iv) using an additive model of the selected variables. As a preselection, the following climatic variables were identified with substantial support: March mean temperature, March precipitation, April mean temperature, June mean temperature, June precipitation (negative), July mean temperature. The slight increase of the mean number of fledged chicks over 59 years could be the result of the increasing mean temperature, but in itself it might not be strong enough to prove that climate change will overall benefit White Stork productivity. Higher temperature and precipitation values are favourable, probably because of the higher biomass, providing more prey, but high precipitation is unfavourable until the thermoregulation of chicks is not developed. Decreasing amounts of precipitation may cause loss of wetlands as suitable feeding sites. Extreme weather is important to complement the picture given by climate change.