Primi dati sull’uso dell’habitat in una popolazione siciliana di Natrix natrix.

First data about the habitat use in a population of Natrix natrix from Sicily. In the present paper the preliminary results of an investigation carried out on a Sicilian population of the grass snake (Natrix natrix) are reported. The leading aim of this study is to compare habitat use among three different classes of individuals (males, females, immatures), using as input the density of observations in four habitat types. Field studies were conducted beside a reservoir (“Lago di Scanzano”), located about 40 km from Palermo (western Sicily). Our results indicate spatial and temporal differences among groups. Young individuals were observed more frequently between April and May along wet meadows dominated by knotgrass, while adults between August and October along the stone pitching of the dam (mainly females), and in a cork oak wood fragment (mainly males). The Kernel analysis shows a low spatial overlap among groups, especially between adults and young individuals. The preliminary results suggest that shelter and prey availability could affect separation among groups.