Surveying woodland raptors by broadcast of conspecific vocalizations

We surveyed for raptors in forests on study areas in five of the eastern United States. For Cooper's Hawks (Accipiter cooperi), Red-shouldered Hawks (Buteo lineatus), and Barred Owls (Strix varia) the contact rates obtained by broadcasting taped vocalizations of conspecifics along roads were significantly greater than contact rates obtained by only looking and listening from the roadside. Broad-winged Hawks (B. platypterus) were detected only after their calls were broadcast. Most raptors were detected within 10 min of the beginning of the broadcasts. Red-tailed Hawks (B. jamaicensis) and Goshawks (A. gentilis) nested infrequently on our study areas, and we were unable to increase detections of these species. Generally, point count transects along woodland roads, from which conspecific vocalizations were broadcast, resulted in higher species specific detection rates than when walking, driving continuously, or only looking and listening for raptors at roadside stops.