The diet of Canary Islands Stonechat was determined by faeces analysis and the identifi cation of prey fragments (invertebrates) of diverse breeding sites on Fuerteventura (Canary Islands). In the faecal samples a total of 1374 prey items was identified. They represent a broad dietary spectrum (at least 12 orders and around 30 families of arthropods) in which Hymenoptera and Coleoptera (most importantly Formicidae and Curculionidae) quantitatively dominate. Approximately half of all prey items identifi ed had a body length of less than 4 mm, and almost 80 % less than 6 mm. Prey species, and their sizes, differ between individuals as well as between various areas and times. Probably in connection with the low biomass of the prey animals, extended energy-consuming hopping along the ground patrolling was rarely observed as a foraging technique. The consumption of berries (Lycium intricatum) represents a supplement to the diet. Within the range of prey size that is morphologically possible and energetically profi table for the Canary Islands Stonechat, the species takes, depending on the immediate environmental conditions, principally small to very small items. Compared with the size of prey taken by adults, the young are fed relatively large items. The reasons for the small size of this chat’s prey animals are thought to be the limited arthropod food supply in extreme and arid climatic conditions, as well as competition pressure from other passerines. The relatively long bill (compared with other chats S. rubetra, S. torquata) could be interpreted as an ecomorphological adaptation enabling the species to occupy this niche.

Prey selection, prey size, faeces analysis, Canary Islands stonechat, Saxicola dacotiae, Fuerteventura