Estudi de la dieta del duc (Bubo bubo) al Baix Empordà

Abstract

The diet of the eagle owl, Bubo bubo (Linnaeus, 1758), has been studied in Europe and the Iberian Peninsula, but less studied in Catalonia. The principal prey in the Iberian Peninsula is the rabbit, whereas in Catalonia this one has lower importance and it is complemented with the rat. Some studies demonstrate variations in the diet because of the habitats that compose the home range. The objective of the study is to analyse the diet of the eagle owl to know its composition and the contribution of the biomass. Also, to determine if there are relations with the home range/hunting area (25 km2) of the territories. The methodology used to determine the diet has been a collection of the prey remains in the nest, obtaining the historic diet of the nesting season. It has been collected samples of six different territories (3 coastal and 3 inland) in Baix Empordà region, Catalonia. The diet is based principally in mammals (57,9%) and birds (41,3%), with a low representation of amphibians and reptiles. The prey that has been more hunt is Rattus sp. with a 40,2%, followed by Columba sp. (15,0%), Erinaceus europaeus (7,7%), Fam. Corvidae (5,9%), Oryctolagus cuniculus (5,8%) and small passerines (4%). Related to the biomass contribution of the preys, Rattus sp. is the highest with a 29,2%, followed by Erinaceus europaeus (22,6%), Columba sp. (17,8%), Oryctolagus cuniculus (11,6%) and Fam. Corvidae (4,9%). No solid conclusions have been drowned about the variation of the diet according to the proximity to the sea. It has been concluded that in the studied territories there is a diet variation in function of the home range habitats. There is an increment of hedgehogs in forestry areas, and an increment of rabbits and red-legged partridge in crops and scrubs zones. This study will contribute to the knowledge for the conservation of the eagle owl, a species that is considered an indicator of a healthy ecosystem due to the role of the top predator