Wintering White-Tailed Eagles Haliaeetus albicilla in the Netherlands: Aspects of Habitat Scale and Quality

The coastal wetlands of The Netherlands have always served as winter haunts for juvenile and immature White-tailed Eagles from breeding populations further north and east. Even as these populations were at their lowest ebb by the 1960s and 1970s, each winter a few individuals showed up, invariably favouring large wetlands with a good supply of wintering, mainly herbivorous, waterfowl. An analysis of the presence of eagles in the wetland Oostvaardersplassen showed that wintering numbers as well as the duration of individual stays increased as a function of the number and biomass of waterbirds present. During the pioneering stage of this newly reclaimed area the dynamic vegetation produced huge seed supplies that attracted vast numbers of herbivorous waterbirds. The increase in eagle numbers in the Oostvaardersplassen reserve preceded the recovery of the northern and eastern breeding populations of Whitetailed Eagles, but did not increase any further after reaching a maximum of 3–4 wintering birds, despite ...