Een vast vangplaats voor Buizerds Buteo buteo: enkele resultaten
De Takkeling , Volume 23 - Issue 3 p. 228- 237
In a study plot in the province of Friesland the breeding biology of Buzzards has been registered since 1998. Nests are located and its content recorded, and moulted feathers of the breeding birds systematically collected (for individual recognition). From 2009 onwards, of the annually 50-60 breeding pairs most birds have been photographed to improve individual recognition. Moreover, in late 2010 a program was initiated to capture with a bal-chatri as many Buzzards as possible, preferably local breeding birds, to retrap ringed birds and to take photographs. In winter 2010/11 a follow-up program was started to trap Buzzards at a Constant Feeding Site where carrion was being provided. Numbers captured showed wide variations per winter, i.e. respectively 4, 9, 16, 7 and 7 Buzzards (2010/11-2014/15) and 1, 1, 0, 0 and 2 Goshawks. Interference competiton was noted between both species, normally with Goshawks on the receiving end of the interactions. Some Buzzards were repeatedly captured and photographed (using wildlife cameras), allowing reconstruction of condition and moult strategies over the years. Also, some Buzzards were only seen (and captured) in winter, among which a bird that had been captured in November 2012 and of which a moulted feather (on which the ring number had been stamped in Friesland) was freshly found in Schleswig-Holstein (northern Germany) in the breeding season. This bird was recaptured several times in Friesland in later years (apparently faithful to its wintering site). The oldest Buzzard captured so far was in its 17th calender-year. The results of this Constant Feeding Site, in combination with the other programs running to follow individual birds, is important in elucidating life histories.
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