KLEEFSTRA R (2010) Monitoring geese on night roosts in the central lake district of Friesland 1998-2010. LIMOSA 83 (4): 160-167.

Although the Frisian lakes, swamps and coastlines are known for their enormous concentrations of geese on night roosts, the actual numbers involved are poorly known. This became clear once more when important bird areas in The Netherlands were selected for the European Birds Directive, now Natura 2000. This was the reason for some volunteers to start up roost counts in the central lake district of the province of Friesland. Between November 1998 and March 2010 the geese on roosts in the Natura 2000-areas 'Sneekermeergebied' and 'Witte en Zwarte Brekken&##9; were counted monthly. Lake Sneekermeer turned out to be of great international importance for White-fronted Goose Anser albifrons and Barnacle Goose Branta leucopsis, with seasonal maxima exceeding 100,000 and 95,000 birds respectively. Lake Witte and Zwarte Brekken is a main area for Pink-footed Goose Anser brachyrhynchus, with maximum numbers up to 12,000 (Table 1). For most species the numbers on the roosts are much higher than on the foraging grounds in the surroundings, where geese are counted monthly as part of the national waterfowl monitoring scheme. This shows that regular roost counts are needed to find out how important wetlands really are for geese.
      In recent years numbers of geese on the roosts in the central lake district have shown a decline, which might be the result of a new goose policy in The Netherlands since the winter of 2004/05. 80,000 ha of foraging areas for wintering geese were assigned on agricultural land where geese are left in peace; outside these foraging areas they are chased and hunted. Insufficient foraging space was assigned near the considered Nature 2000-areas and it is now even possible for hunters to hunt close to the roosts. Continuing the geese counts on roosts will make it possible to monitor this recent development.

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