Long-term changes in petrel populations on Inaccessible Island, Tristan da Cunha, inferred from the diet of Brown Skuas Stercorarius antarcticus

A four-decade analysis of Brown Skuas' diet on Inaccessible Island reveals minimal long-term changes, despite shifts in prey composition. Petrels dominate the skua diet (94%), with Fregetta storm petrels, White-faced Storm Petrels, and Broad-billed Prions comprising over 98% of avian prey. Seasonal variations align with petrel breeding phenology, while increases in fur seals and Great Shearwaters in the diet suggest population growth, contrasting with potential declines in Common Diving Petrels and Subantarctic Shearwaters. Tarsal length changes hint at species composition shifts within Fregetta storm petrels. The study infers petrel population trends by analyzing regurgitated pellets and prey remains, offering insights into the dynamics of burrowing seabird communities on this remote World Heritage Site.

Ryan, P. G. (2023). Long-term changes in petrel populations on Inaccessible Island, Tristan da Cunha, inferred from the diet of Brown Skuas Stercorarius antarcticus. Ostrich, 95(2), 163–171. https://doi.org/10.2989/00306525.2023.2269479