Assessment of the consumption of the exotic Asian Hornet Vespa velutina by the European Honey Buzzard Pernis apivorus in southwestern Europe

ABSTRACT Capsule The Asian Hornet Vespa velutina was the second most important species in the diet of the European Honey Buzzard Pernis apivorus in southwestern Europe, just four years after the appearance of the exotic wasp in the study area. Aims To assess the consumption of the invasive Asian Hornet by the European Honey Buzzard in southwestern Europe, following the Asian Hornet’s appearance there in 2014. Methods In northwestern Spain, we installed trail cameras in, and collected wasp comb remains from, nine nests of European Honey Buzzards (five in 2018 and four in 2019). We estimated the representation of the Asian Hornet in the birds’ diet, as well as the number of colonies attacked. We also compared the nesting frequency and density of breeding pairs before (2004–13) and after (2014–20) the Asian Hornet’s appearance. Results We detected consumption of the Asian Hornet at all the nests we examined. The Asian Hornet was the second most abundant wasp species in the diet and it was the most abundant in 2018 based on biomass. During the breeding season, each pair of European Honey Buzzards attacked 34–61 colonies in 2018 and 15–28 in 2019. Nesting frequency rose from 60% before the Hornet’s appearance to 100% afterward, while the density of breeding pairs increased by 300%. Conclusion Our results suggest that the Asian Hornet is becoming an important part of the diet of the European Honey Buzzard. This finding opens a research avenue to assess the potential role of the raptor in the management of the invasive social wasp.