De Sperwer Accipiter nisus als broedvogel in de provincie Groningen in 2015

During a partial survey of the province of Groningen in 2015, slightly more breeding pairs of Sparrowhawks were recorded than in previous years. In three municipalites surveyed annually since 2012, respectively 23, 25, 24 and 30 breeding pairs were located. Based on all surveys in 2012-15 and their accuracy, the expected number of Sparrowhawk territories for each municipality is calculated. So far, 66-83 pairs have been located, resulting in an estimate of 147-198 pairs for the 232,541 ha of the province of Groningen. Breeding success was slightly smaller than in 2014, with 3x 1, 1x 2, 4x 3, 2x 4 and 2x 5 chicks per nest (mean 3.2). Start of laying averaged 30 April (range: 20 April-7 May). On three nests (21%) chicks were found to be infested with louse flies Hyppoboscidae. Pluck sites were searched for rings of prey, using a metal detector. Out of 21 rings found, 15 belonged to first calender-year passerines. Most prey had been ringed within 1 km of the breeding site, but rings were found from sites as far as 243-445 km in Belgium and France respectively.