HABITAT USE BY PARTRIDGES (PERDIX-PERDIX AND ALECTORIS-RUFA) IN AN AREA OF NORTHERN APENNINES, ITALY

Habitat selection by grey and red-legged partridges was studied in an area of 94.5 km2 in northern Italy. A total of 376 observations of grey partridges and 211 of red-legged partridges were collected during two years of study (1984 and 1985). Habitat overlap and breadth were similar in the two species; both species avoided woods and chose hedgerows in spring and summer but in autumn-winter selection of permanent cover differed: grey partridges selecting hedgerows and red-legged partridges calanques and landslides, the driest habitats in the study area. Significant differences were also found for nesting site selection: grey partridges preferred the edges of habitats and hedgerows, while red-legged partridges selected the centre of habitats, vineyards and uncultivated land. In general, grey partridges seemed to be more linked to crops and open land than did red-legged partridges and this latter species needs a similar habitat in cover structure and micro-climate to those of its zones of origin. The competition hypothesis to explain the differences in habitat use between the two species does not apply because of low population densities and high habitat availability. Consequently the most acceptable hypothesis is that the two species select different habitats because of their zoogeographic origin.