Dawn and Morning Goshawk Courtship Vocalizations as a Method for Detecting Nest Sites

Abstract

My paper discusses a northern goshawk (Accipiter gentilis) nest-detection method that relies on listening for spontaneous dawn and morning vocalizations. The study was conducted in a woodland area (approx 4,000 ha) of the Burgundy region, France, in 1996. To determine the frequency and the distribution of annua and daily vocalizations I conducted systematic listening sessions throughout the year. The duration of adult goshawk vocal events during the year displays 1 major peak in the courtship period. In this period the vocal events have I major peak in the first hour preceding sunrise and in the following 3 hr. In 1997, to test the efficacy of the method, I performed an investigation on 21 known goshawk nest sites: I detected goshawk presence in 100% of trials. To achieve the highest effectiveness in the use of spontancous goshawk vocalizations, listening sessions should take place during the 3 months preceding egg laying and be conducted from 30 min before sunrise to about 200 min afterwards.