Predator-Prey Dynamics Between Eurasian Sparrowhawk and Its Bird Prey During Spring Migration in the Forests at Hel...

Climate change in Europe can influence the predator-prey interactions, a scarcely studied topic in birds. We examined relationships between the spring passage timing of the Eurasian Sparrowhawk, a generalist peak predator, and its main bird prey species (Song Thrush, Eurasian Blackbird, Common Chaffinch, Great Tit, European Robin). All species were ringed daily (26 March-15 May) in 1982-2021 at Hel Peninsula (N Poland). In 2024, we collected pluckings to identify Sparrowhawks' prey. Sparrowhawks' daily migration dynamics and those for the Song Thrush, Robin and Chaffinch were correlated. Sparrowhawks' median dates of passage showed no multi-year trend, but large variation, correlated with those of its prey and with temperatures. Adult females and males migrated through Hel early after warm February and March at wintering grounds. Young males migrated early during warm Aprils at Hel. Medians were correlated between adult males and Robins, adult females and Blackbirds, and young females and Song Thrush. This suggests that Sparrowhawks adjust their migration timing each spring to the availability of these three prey species, with some sex differences, as males are smaller than females. Identifying changes in predator-prey dynamics in response to climate change helps us understand its effect on forest ecosystems.