Toenemend aantal Toendrarietganzen Anser serrirostris rossicus op het Fochteloërveen

The Fochteloerveen is a large peat moor (2000 ha) in an open agricultural landscape in northwestern Drenthe. Bean geese are foraging on leftovers of potatoe, beet and green maize crops. During periods of prolonged frost they shift to foraging on grassland. The birds use roosting sites on open shallow water in the peat moor, but when these are covered by ice, they shift to deeper waters in nearby sandpits. In 1997-2001, geese were counted weekly on their foraging sites and occasionally at the roost. Numbers amounted to several hundreds before the winter 1978/79 and increased to 14.000 in 2001, i.e. more than 2% of the estimated world population (Table 1). In recent years the birds seem to arrive earlier in their wintering area (Table 2). In the 1970s only Anser fabalis fabalis was visiting the Fochteloerveen. Presently, this species is rarely seen. Nowadays almost all geese are A. serrirostris rossicus, with the occasional small group of A. s. serrirostris. The increase in numbers might be explained by better roosting conditions (higher water table in the peat moor) and several wet summers and autumns in recent years, resulting in an abundant food supply as crops were not harvested.