Aantalsontwikkeling van broedvogels in Boschoord in 1967-2013

Dijk A.J. van 2013. Breeding birds in Boschoord in 1967-2013. Drentse Vogels 27: . In the mixed and coniferous woodland of Boschoord (670 ha, table 1) in the northern Netherlands, all breeding birds have been censused since 1967. Rare breeding birds were counted every year, scarce species with an interval of 2 or 4 years, and common species with even longer intervals in in two plots of 20 and 38 ha each (Table 2). The breeding population comprised 107 species. Within this time frame, 26 species showed an increase, such as Stock Dove, Marsh Tit and Great Spotted Woodpecker. This category also includes colonizers like Lesser Spotted Woodpecker, Nuthatch and Hawfinch (fig. 1). Thirty-two species showed a decrease, including Turtle Dove, Long-eared Owl, Tree Pipit and Redstart, whereas Black Grouse, Pheasant became extinct and Linnet nearly so. More or less stable or fluctuating populations were found in 33 species, among others Woodcock, Green Woodpecker, Mistle Thrush, Firecrest, Wood Warbler, Crossbill and Siskin. Sixteen species were found to breed occasionally. Over the years, the composition of woodland changed from predominantly coniferous to a mixture of coniferous and deciduous, and as consequence the breeding bird fauna showed a similar change in species composition and abundance (species confined to deciduous and mixed woodland nowadays outnumber those of coniferous forest).