Female turnover rate differs between two Northern GoshawkAccipiter gentilisnesting areas, as revealed by DNA analysis of moulted feathers

Abstract

The turnover rate of breeding Northern Goshawk Accipiter gentilis females in two study areas in southern Norway, which are assumed to experience different levels of illegal human persecution, was estimated using DNA extracted from moulted feathers, along with other characteristics. Female turnover rate over a 4-year period for each nesting territory during 1990–2015 was significantly higher in Aust-Agder County (31.9%; 23 territories), where hunters have long shown antipathy to Goshawks, than in Telemark County (17.3%; 25 territories). Turnover rate was not related to territory quality. The proportion of successful nesting attempts was lower in Aust-Agder (70–75%) than in Telemark (82–84%), but for newly built nests, which are less likely to be known by hunters, the difference was not significant (77.4 vs 79.6%). The proportion of juvenile female Goshawks among recruits and in the total breeding population also did not differ between the two areas. Our findings support the notion that Goshawk persecution was higher in Aust-Agder than in Telemark. We found that the use of phenotypic characteristics for individual recognition was successful in 96.2% of 130 comparisons of female Goshawks from two consecutive nesting attempts, when assessed using genetic markers.