Diet of common ravens on El Hierro, Canary Islands

The Common Raven (Carvus coraxi on El Hierro, an oceanci island in the Canary archipelago, is omnivorous. Although ravens from five regions on El Hierro showed qualitatively similar diets, there were considerable quantitative differences. Diet in wet and dry pastureland was made up principally of animals invertebrates at Jinama (frecuency of occurrence in pellets = 84.8%) and high levels of vertebrates at Bascos (60%). Spring was characterized by the consumption of vertebrates (frecuency in pellets = 48.5%), summer by invertebrates (77.1%), and autumn/winter by a diet of plant material (92.6% and 96.9%, respectively). White diets in many continental environments are often characterized by vertebrates throughout the year, ravens on El Hierro tend to be omnivorous, including many insects and wild fruits in their food.

L dieta del cuervo (Corvus corax) en la isla de El Hierro, Islas Canarias, es omnívora. Aunque cinco zonas estudiadas no mostraron gran variación respecto al tipo de alimento, hubo considerables cambios cuantitativos. En los pastizales de Bascos (seco) y Jinama (húmedo) la dieta consistió básicamente de materia animal. Hubo invertebrados en abundancia en Jinama (frecuencia de aparición en egagrópilas = 84.8%) y restos de vertebrados en el de Bascos (60%). Desde el punto de vista estacional, la primavera se caracterizópor el consumo de vertebrados (77.1%), y durante el otoño y el invierno se alimentaron intensamente de materia vegetal (92.6% y 96.9%, respectivamente). Mientras la dieta del cuervo se caracteriza básicamente por la presencia de vertebrados en los ecosistemas continentales, en áreas insulares, como El Hierro, el ave es omnívora, incluyendo en su dieta abundantes insectos y materia vegetal.

This article has its origins in a chapter from the Ph.D. thesis of the first author of this paper. We would therefore like to express our thanks to the supervisors, Aurelio Martín and Pedro Jordano, for reading and providing valuable comments on the manuscript. Duncan Brooks and Vicente Quilis revised and made helpful comments on the text. Two anonymous referees and R. Chandler made valuable suggestions that helped to improve the manuscript.

Peer reviewed