Edge preference of a synanthropic species along a rural-urban gradiente: the case of Blue Rock Thrush

ABSTRACT. – We carried out a quantitative mapping method to test the edge preference of a synanthropic species (Monticola solitarius, Aves, Passeriformes) in a small town of central Italy. In particular, using non parametric tests, logistic regression and Analysis of Covariance, we tested the following hypotheses: (i) males place their singing sites in edge locations when compared to random sites and, (ii) the singing areas are less urbanized when compared to random ones. In our study area, this species placed their singing sites in contexts that are significantly more thermo-xerophilous, less urbanized and more distant from the urban centre, when compared to random selected sites. The urban cover is significantly different between singing sites and random sites also once the effect of distance from centroid of study area is accounted for. These data quantitatively confirm previous descriptive evidence suggesting as territories of this insectivorous aerial forager were mainly located near the edge border of the towns with higher food availability. We suggest that open vegetated habitats in built areas may represent ‘critical habitat features’, i.e. ecological patches that are critical to certain life-history and ecological requirements of this synanthropic species. This is the first quantitative study limited to a species-specific edge preference. We foster further research on this peculiar trait also for other synanthropic species.