Waarnemingen in een wespendiefterritorium Pernis apivorus in oostelijk Holstein in 1969-2009

Between Liibeck and Neumiinster, eastern Holstein in Germany, a local Honeybuzzard pair was observed in the small forested estates of Diekhof and Perdol (53°59’N, 10°30’E) between 1969 and 2009. The estates are structurally diverse, with old Fagus sylvatica (140-150 yrs) interspersed with Quercus robur, Larix, Abies grandis, Alnus glutinosa and swamps, ponds and peat moor. Since 1969, moulted feathers of Honey-buzzards were collected (often near nests of Red Kites Milvus milvus), and the first Honey-buzzard nest was recorded in 1971 when the finding of moulted feathers of the adult female (six rectrices, most likely shed during fright moult) led to the nest’s discovery in a small stand of Picea abies. Moulted feathers collected in 1969 and 1970 indicate that this nest may have been occupied for some time already. This nest remained in use up to and including 1976 (successful in 1971, 1973 and 1976), even when a comparison of moulted feathers – used to recognise birds individually – seemed to indicate that several changes in pair composition took place in the mean time (female replaced in 1971 and again in 1973, male the same in 1973-76 but apparently absent in 1974). Breeding was apparently not even attemped in 1972 and 1974, when summer conditions were cool and wet, and wasp numbers poor. Although the summer of 1975 was above-average warm and dry, spring weather was particularly cold in late May and early June, the period when wasp queens start to emerge. Despite high wasp numbers in 1977, the Honey-buzzard nest was found deserted, although the Diekhof estate was being visited by at least one Honey-buzzard according to the scattering of moulted feathers (small feathers only). No evidence for the presence of Honey-buzzards was found in 1979-80 (poor wasp numbers, on average adverse weather during summer), not even during autumn migration. Breeding was again observed in 1981 (successful), a year with high wasp numbers, and in 1982 (failed, presumably because of depredation of one of the adults), in a new nest in a stand of old beech. No breeding was recorded from 1983 onwards.