Situación del Cuervo (Corvus Corax) en la Región de Murcia

Abstract

Ravens (Corvus corax) have experienced a strong population fall in the Region of Murcia and have almost disappeared in the coastal area. The aim of this report is to show the distribution of this species, a potential distribution model from nest sites where a recent breeding has occurred, and density values per regions and in the largest municipalities. From 2005 to 2008, we revised cliffs where ancient presence of ravens was known (recently occupied and deserted nest sites), and we have prospected those areas with suitable features for ravens’ presence. From the available information about occupied nest sites, an Ecological Niche Factor Analysis (ENFA) model which predicts potential distribution of ravens has been generated. Out of the 79 nest sites that have been recorded, 47 are occupied and 32 are deserted. Most of current nests are located in cliffs. The species is distributed over almost all the Region of Murcia, being more abundant in the central-northwestern area – matching the areas being the steepest, having the highest altitude and having the highest forest cover – less present in the central-eastern area, and almost absent on the coast. The obtained average regional density is 1 nest site / 143,21 km2, but just considering current nest sites, this value is reduced to 1 nest site / 240,72 km2. Highest densities are found in Bajo Guadalentin, Cuenca de Mula and Noroeste regions, especially in Mula and Moratalla. With the carried out preliminary record, a significant decrease in the regional population has been observed in the last decades – 40% of nest sites being lost – being more prominent on the coast than in inland areas.