Use of roadsides by diurnal raptors in agricultural landscapes

Abstract

In a 2772 km survey in western France, we compared the relative abundance and activity of diurnal raptors along motorway verges and secondary roads to those in open cropland, during different seasons and hours of the day. Motorway verges, and to a lesser extent secondary road verges, were used significantly more than adjacent areas by buzzards ( Buteo buteo), kestrels ( Falco tinnunculus) and black kites ( Milvus migrans), but not by harriers ( Circus aeruginosus, C. cyaneus, C. pygargus). There was a seasonal shift in the use of roadsides by buzzards and kestrels, with a high use of motorway verges in winter and a low use in summer. Although kestrels and buzzards clearly used verges for hunting, their abundance along roads was not directly related to the relative abundance of small mammals. The supply of perching sites, allowing a less energy-demanding hunting behaviour than flight-hunting, and the width of the verges, appeared important factors in the attractiveness of roadsides for these species. This study shows that roadsides, particularly wide motorway verges, can be managed with respect to the conservation and abundance of raptor species in agricultural landscapes, in providing stable prey habitats and perching sites.