Preliminary data for a comparative study of the feeding habits of Asio otus canariensis on El Hierro and Gran Canaria, Canary Islands

Abstract

From analysis of 4.446 prey items, the diets of Asin otus canariensison El Hierro and Gran Canaria islands are contrasted and also compared with the data given for Tenerife. Muridae form a substantial part of this owl's diet-up to 92.8% of the total biomass. This applies to all habitats studied, except for the endemic pine forests, where they are partially replaced by rabbits. In addition, the local use of alternative trophic sources such as birds and reptiles is confirmed. In relation to European populations of the Long-cared Owl. several differences are noted: (I) an increase in the taking of reptiles, especially Gekkonidae. (2) a high degree of entomophagy, the families most preyed on being Tettigoniidae and Gryllidae. (3) a certain euryphagous degree.