Geen sprookje maar werkelijkheid: een 3-legsel bij een Wespendief Pernis apivorus

After preliminary observations of wing-clapping Honey-buzzards in late summer 2002, wing-clapping was again observed in May 2003 above a woodlot in the valley of a small stream. When checking a Common Buzzard Buteo buteo nest in this woodlot on 18 June, an incubating adult on 3 eggs was recorded. One of the eggs was pipping on 10 July, and 3 chicks were seen on 25 July. During ringing on 7 August, maximum wing chords were 205, 193 and 145 mm (i.e. 24, 23 and 19 days old). Onset of laying was back-calculated at 9 June. On 2 September both oldest chicks were branching, the youngest was still on the nest. All three were flying by 8 September. During nest visits, few wasp combs were found on/undemeath the nest (consistent with poor wasp numbers overall in 2003, i.e. wasp index 2 on a scale of 1-5; Rob G. Bijlsma), but depredated frogs were encountered each time. Several large samples in The Netherlands showed that a clutch size of 3 eggs is rare, viz. 8x C/1, 175x C/2 and 3x C/3 (in 1976, 1982 and 1986, one of which resulted in 3 fledglings) on Veluwe and in Drenthe in 1971-2003 (Rob G. Bijlsma) and 3x C/1 and 120x C/2 in The Netherlands in 1996-2002 (Dutch Raptor Group).