Is the red-legged partridge Alectoris rufa naturally colonising the north of Lazio region, Italy?

Abstract

The present study aimed to update the distribution of the red-legged partridge Alectoris rufa in Central Italy, with particular reference to the northern Lazio Region. This species was introduced into the regions of Umbria, Lazio, Molise, and Toscana, where it has partially acclimatized. Several reports on the species’ presence and reproduction were reported from the northern Viterbo province, suggesting the necessity of a survey. Between 2010 and 2011, local people were interviewed (forestry agents, keepers, hunters and farmers), and a field survey was performed utilizing detection signs of presence and playback counts. All data were recorded in a geodatabase. Signs were georeferenced in a grid of 3,864 territorial units (TUs; 1 km x 1 km). Red-legged partridges were found in 190 TUs (19,000 ha): brigades, composed by 6 individuals on average, within 31 TUs; breeding pairs within 31 TUs; single birds within 128 TUs. To confirm the presence of breeding pairs, a playback survey schedule was performed throughout the spring of 2011 in a random sample of cells (28.9% of the cells in which the presence of the species had been reported) along line transect of 118 km length in total. Playback survey confirmed the presence of 25 breeding pairs and 6 single individuals within 31 TUs. Because the province of Viterbo did not perform restocking of the species, the detected distribution appears to be caused by the natural expansion of populations from Toscana and Umbria regions. Further studies are currently in progress to better appreciate the population parameters.