Moult and age determination of Eurasian sparrowhawks Accipiter nisus in Spain
Published: Volume 56(2), December 2009. Pages 241-251.
The moult sequence of sparrowhawks in Spain and its variations regarding the previously described pattern, and how to use it for on-hand age determination of individuals is described. Eighteen adult sparrowhawks were trapped during the breeding seasons between 2001 and 2007 in Vizcaya and 129 sparrowhawks were examined in Wildlife Rehabilitation Centres between 1999 and 2007, including individuals from Vizcaya and Alava (Northern Spain), Madrid, Guadalajara, Salamanca and Toledo (Central Spain), and Granada and Jaén (Southern Spain). A total of 147 full-grown sparrowhawks were analysed in order to determine the moult sequence. The moult in primaries and their respective primary coverts went in order from the innermost (P1) to the outermost (P10). The moult of secondaries started in four separate moult foci, S5 being normally the first to be shed; afterwards the second focus was located in S11, the third was located in S1 and the fourth in S13. The moult of rectrices usually started in the central pair followed by R4 and R6, while R5 and specially R2 were the last tail feathers moulted. The moult started in June and finished in November. 18.75 % of breeding females and 55.5 % of breeding males had arrested the moult. None of the breeding birds retained flight feathers from the previous season, whilst 32 % of the wintering females and 30 % of wintering males presented retained feathers. Sparrowhawks in Spain follow closely the pattern described by Newton and Marquiss (1982) for Scottish sparrowhawks. However, the effect of wintering birds on the sedentary population and other variables provoke some differences with regard to the Scottish model. These data can be used as a tool to determine the age of Spanish sparrowhawks and could be hypothetically used to distinguish wintering birds from local populations.