Dawn and morning goshawk courtship vocalizations as a method for detectingnest sites

My paper discusses a northern goshawk (Accipiter gentilis) nest-detection m ethod that relies on listening for spontaneous dawn and morning vocalizatio ns. The study was conducted in a woodland area (approx 4,000 ha) of the Bur gundy region, France, in 1996. To determine the frequency and the distribut ion of annual and daily vocalizations, I conducted systematic listening ses sions throughout the year. The duration of adult goshawk vocal events durin g the year displays 1 major peak in the courtship period. In this period, t he vocal events have 1 major peak in the first hour preceding sunrise and i n the following 3 hr. In 1997, to test the efficacy of the method, I perfor med an investigation on 21 known goshawk nest sites: I detected goshawk pre sence in 100% of trials. To achieve the highest effectiveness in the use of spontaneous goshawk vocalizations, listening sessions should take place du ring the 3 months preceding egg laying and be conducted from 30 min before sunrise to about 200 min afterwards.