KLEEFSTRA R, HOOIJMEIJER J & NIJLAND F (2023) Geese on night roosts in the province of Friesland in 1996/97-2016/17. LIMOSA 96 (1): 30-43.

The Dutch province of Friesland is of great importance as a wintering area for geese. Every year, the province hosts more than 40% of all migrating and wintering geese in the Netherlands. In the foraging areas they have been counted for decades under the coordination of Sovon. In Friesland, however, also numbers of geese on night roosts have been counted, since the late 1990s on the initiative of the ‘FFF-Roost Survey Group Fryslân’ of the volunteers’ organization Fryske Feriening foar Fjildbiology (FFF).
In this article we give an overview of 21 years of geese counts on 50 inland night roosts (Appendix 1, Fig. 1). For the five most numerous species (Tundra Bean Goose Anser serrirostris, Pink-footed Goose Anser brachyrhynchus, White-fronted Goose Anser albifrons, Greylag Goose Anser anser and Barnacle Geese Branta leucopsis; Tab. 1-6) we give an overview of the most important night roosts and, if possible, the change in numbers over three periods of seven years. For Pinkfooted Geese also an integral count of night roosts in the winter of 2001/02 is given (Tab. 3). Night roosts with very high numbers of geese are mainly found in flooded grasslands, shallow water coastlines, and peat pools and puddles. Most of these important night roosts are protected under Nature 2000-legislation, but some important night roosts lack formal protection.
Monthly counts in the period October-March can give a good impression of the numbers of geese using a nature area for night roosting. As far as possible, trends indicate decreasing numbers of Pink-footed Geese, related to wintering further north, but possibly also due to an increasing disturbance by hunting on the edges of night roosts in some areas. This might also affect numbers of White-fronted Geese and Barnacle Geese on some of the most important night roosts. Greylay Geese show an increase on most roosts.

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