Dietary Characterization of Savi's Warbler Locustella luscinioides and Great Reed Warbler Acrocephalus arundinaceus in Eastern Spain

Abstract

This research deals with two insectivorous reedbed-nesting songbirds: the Savi's Warbler Locustella luscinioides and the Great Reed Warbler Acrocephalus arundinaceus, breeding at the Marjal de Pego-Oliva (Valencia-Alicante, Spain). We studied the diet and prey selection of the two species and assessed the dietary differences between them. Diet composition was assessed by examining samples of regurgitated food obtained using apomorphine as an emetic. Prey availability was estimated through standardized invertebrate sampling. The diet of the two warblers was significantly different and included arthropods belonging to the orders Araneida, Coleoptera, Hymenoptera, Hemiptera, Diptera, Mantodea and Orthoptera. The most frequently found prey were Araneida and Coleoptera in the diet of Savi's Warblers, and Hymenoptera and Coleoptera in the diet of Great Reed Warblers. Both species positively selected Araneida and Coleoptera and avoided Diptera, while for other arthropod taxa prey selection differed between the two warbler species.