2025/07/08 by Michael J. Thornton, Darren Wilson, A. F. LEITCH +2 · 1 voice · 1 citation
Environmental Science · #Avian ecology and behavior #Marine animal studies overview #Ichthyology and Marine Biology
paper · doi:10.1080/00063657.2025.2513542
Capsule The garden bird community composition in Edinburgh changed over three decades, probably in response to increased supplementary feeding, which has increased prey biomass for Eurasian Sparrowhawks, coinciding with a significantly larger clutch size of sparrowhawks over the same period.Aims To study the potential impacts of a changing avian prey community on Eurasian Sparrowhawk breeding success.Methods We used a range of datasets to explore how changing trends in garden bird abundance in Edinburgh, UK, might impact on the diet and breeding success of Eurasian Sparrowhawks.Results Several important Eurasian Sparrowhawk prey species increased in abundance in Edinburgh from 1998 to 2019, including Common Wood Pigeon Columba palumbus, European Goldfinch Carduelis carduelis and House Sparrow Passer domesticus, and others showed decreases, including European Starling Sturnus vulgaris, European Greenfinch Chloris chloris and Eurasian Chaffinch Fringilla coelebs. These were similar to UK trends for garden bird populations. The Eurasian Sparrowhawk’s diet shifted towards smaller and larger prey compared to an earlier study from 1986 to 1989. Prey making an increased contribution to the Eurasian Sparrowhawk’s diet consisted of larger species, such as Common Wood Pigeon, Feral Pigeon Columba livia and Eurasian Magpie Pica pica. For key prey species, there was a significant correlation between population trends during 1998–2012 and change in the species' proportion in diet composition, suggesting changing diet reflected a changing prey base. The Eurasian Sparrowhawk’s diet became more diverse, with a more even range of prey relative to the earlier study. Eurasian Sparrowhawk clutch size was significantly higher in 2009–2015 compared to 1986–1989, increasing by almost one egg per clutch, but there was no significant change in brood size.Conclusion Our results are consistent with a bottom-up trophic effect of the garden bird community composition on the Eurasian Sparrowhawk’s clutch size, but not brood size.