THE DIET OF THE RAVEN CORVUS CORAX IN SOUTH-WEST SLOVENIA

Headnote

ABSTRACT

The diet of the raven was investigated in 2008 in south-west Slovenia. 158 food items, belonging to 26 different food groups, were retrieved from 60 whole and some broken pellets collected during the spring and autumn. Vertebrate remains were found in 57 pellets and plant debris in 53 pellets. Sheep remains were found in 32 pellets, and were significantly more common in pellets from sheep pastures than from areas with no pastures. Deer, invertebrate and bird remains were scarce.

Key words: the raven, Corvus corax, diet, south-west Slovenia

DIETA DEL CORVO IMPERIALE CORVUS CORAX IN SLOVENIA SUD-OCCIDENTALE

SINTESI

Gli autori hanno studiato la dieta del Corvo imperiale nel 2008 nella Slovenia sud-occidentale. 158 pezzi di cibo, appartenenti a 26 differenti gruppi alimentari, sono stati recuperati da 60 borre intere ed alcune danneggiate, raccolte durante la primavera e l'autunno. Resti di vertebrati sono stati ritrovati in 57 borre, mentre resti vegetali in 53 borre. Resti di pecora sono stati riscontrati in 32 borre, risultando significativamente più comuni nelle borre raccolte sui pascoli ovini che in quelle raccolte nelle aree lontane dai pascoli. Resti di cervidi, invertebrati e uccelli sono risultati scarsi.

Parole chiave: Corvo imperiale, Corvus corax, dieta, Slovenia sud-occidentale

INTRODUCTION

The raven population (Corvus corax) consists of birds with two types of social behaviour: breeding birds, which appear to be territorial and live in pairs, and nonbreeding, non-territorial birds, which live year-round in flocks (Ratei iffe, 1997). The raven population in Slovenia is estimated at 2000 to 3000 breeding individuals (1000 to 1500 breeding pairs; Geister, 1995) and at least 1500 to 3000 non-breeding individuals (Tome et al., 2009). Although no quantitative data exists, there are some clues that the population has increased in recent decades (Tome et al., 2009). This increase is consistent with observations all over Europe (BirdLife international, 2004; EBCC 2008) and is thought to be the result of the ban on shooting in some countries and increase of sheep farming practice in others (Tome ef al., 2009). The population size of ravens is known to correlate with the extent of sheep farming (Newton et al., 1982).

The raven is first of all a scavenger and, as such, a vulture substitute in northern Europe ( Rate I iffe, 1997). It...