The Macaronesian Sparrowhawk diet in native and exotic forests

摘要

The Macaronesian Sparrowhawk (Accipiter nisus granti) is an endemic subspecies restricted to the forest habitats of Madeira and the Canary Islands. We studied its inter-habitat diet variation on the largest of the Canaries, Tenerife, during the 2014-2015 breeding seasons. We also compared the current food spectrum (2014-2015) with that reported in a study conducted 30 years ago. Prey remains analyses were conducted at the three main forested habitats, two native (laurel forest and Canarian pinewood) and one exotic (exotic tree plantations). Birds formed the main dietary component of the Sparrowhawk (26 species identified), but mammals and reptiles were also consumed in small numbers. Avian prey of around 200-300 g were preferred by Sparrowhawks. Three species accounted for 63.4% of the total number of prey counted (Atlantic Canary Serinus canarius, Rock Pigeon Columba livia and Blackbird Turdus merula), but their importance varied among habitats. In laurel forests and exotic tree plantations diet niche breadth and prey diversity was greater than in the Canarian pinewoods as reflected by prey densities. A comparison of our data with those from 1984-85 showed that large-sized avian prey might have become more important in the diet spectrum and thus indicating changes in the population status of prey species. The majority of Macaronesian Sparrowhawk hunting habitats are exposed to agricultural and forestry practices that could result in negative population trends of Sparrowhawk prey. Further studies are required to fully understand predator-prey relationships and to develop effective management actions to guarantee the long-term conservation of this island raptor.