Terreingebruik door Wespendieven Pernis apivorus Woodland use of Honey Buzzards
Drentse vogels , Volume 4 - Issue 1 p. 27- 31
Flights of Honey Buzzards were mapped in July and August 1990 in the Forestry of Smilde/Berkenheuvel (3200 ha). Six territories were found, a seventh being present just outside the study area. Territory holders were individually recognised by means of plumage characteristics. Display flights were frequent in July and August, and showed no connection with nest sites whatsoever. Home ranges of males were mapped using all observations of flying, soaring and displaying birds which were individually recognisable (fig. 1). Display flights were centred around the areas with a large food supply (as measured by the number of depredated nests of Vespula vulgaris and V. germanica). Most social wasps preferred 50- 60 year old stands of Picea abies (table 2). It is argued that display flights, which increased in intensity in the course of the summer, are apparently used to demarcate favourable feeding areas, rather than nest sites. Individual recognition is obligatory during a census of breeding Honey Buzzards. The overlap in home ranges is immense (fig. 1, table 1), and whereas not all pairs are soaring or displaying at the same time, it is conceivable that birds of different pairs are combined during the interpretational phase of the survey: an underestimate of up to 50% is possible without individual recognition. Flight lines with a length of 2.5-5 km were noticed in the Forestry of Smilde!
|551774.jpg Cover Image , 5kb|