Use and selection of breeding site and territory by Southern Caracara (Caracara plancus) in Pampean agroecosystems

Birds of prey usually have large home ranges and thus, nesting or foraging habitat selection occurs at multiple spatial scales. Our objective is to provide information on the use and selection of nesting site and nesting habitat by Southern Caracara (Caracara plancus) in an agricultural area of northeaster La Pampa Province. At nesting site level we recorded two variables, substratum tree species and height, in 23 occupied nests and 28 control points. For nesting habitat analysis we defined buffer areas in a 500m radius around the nest tree in 44 occupied nests and 34 control points. In each buffer we measured the surface covered by different land uses. Variables were grouped into five categories. The GLM results showed that at nesting site scale, the Caracaras chose higher trees (p <0.05) than those randomly selected, although they did not choose any particular tree species. At nesting habitat scale Native Forest cover had a negative influence (p=0.05) on territory occupation. In other geographic areas Caracaras also select relatively open sites for breeding. This selection would be related with a reduction in the risk of predation of adults and nestlings in the nest. The absence of clear selection of other variables in nesting territories could be due to the homogeneity of agricultural landscapes. Alternatively, it could be that the selection process occurs on a larger scale than the one evaluated.