KOFFIJBERG K, BEEKMAN J VAN DEN BERGH L, BERREVOETS C, EBBINGE B, HAITJEMA T, PHILIPPONA J, PROP J, SPAANS B & ZIJLSTRA M (1998) Goose and swan numbers in the Netherlands 1990-95. LIMOSA 71 (1): 7-32.

This paper summarises results of goose and swan counts in The Netherlands from 1990/91 through 1994/95, presenting information on numbers and percentage of first year birds (Tabs. 2-13), trends (Fig. 2), seasonal patterns (Fig. 3) and spatial distribution (Fig. 4). A mid-monthly counting scheme runs from October to March (all species: both geese and swans), additional counts being orgamsed for Greylag Geese in September and Brent Geese in May (Tab. I). Prior to 1993, only geese were taken into account whereas census work was mainly undertaken during periods of peak-occurrence of the various species.
      Seven goose and three swan species occur as regular visitors to The Netherlands. Most abundant species are White-fronted, Greylag, Barnacle and Brent Geese. In all species, numbers recorded are of international importance (Tab. 13). Occurrence of Bewick's Swan and Pink-footed, White-fronted, Greylag, Barnacle and Brent Geese highlight the important position of The Netherlands in the West-Palearctic network of flyways. The entire Svalbard population of Pinkfooted Goose stages in the Netherlands in autumn (November).
      In general, maximum numbers are present during mldwmter (December-February, Fig. 3), except for Pmk-footed, Greylag and Brent Geese, which reach peak- numbers during migration: Pinkfeet and Greylag in October/November, Brent in May. Greylag Geese also occur in large numbers (up to 62 000) during wingmoult in June-July in Oostvaardersplassen, Flevoland province. Throughout the season, species such as Lesser White-fronted, Canada and Red-breasted Goose are recorded in small numbers (Tab. 12). Compared with previous data, Pink-footed, White-fronted and Barnacle Geese have changed their seasonal pattern, i.e., arriving earlier in autumn (Pink-footed and White-fronted in September-November) or departing later in spring (Barnacle in AprillMay). The majority of the more important staging areas is situated in the lower, western part of the country; important regions being the Wadden Sea area, the SW part of Friesland province, the Lake IJssel area, the river district and the Delta area (Fig. 4). Especially Whooper Swan, Taiga Bean Goose, Pink-footed Goose and Brent Goose frequent a limited number of sites.
      Since the 1960s, most species have shown a marked increase (Fig. 2). This trend conforms with overall West-Palearctic trends, often attributed to better protection measures (lower hunting pressure), improvement of feeding habitats in winter and/or changes in flyways. Results of Dutch counts suggest that in most species population growth has leveled off during the 1990s. Fluctuations in numbers over the past decades may be due to severe winter conditions, resulting in an influx of species which regularly winter in the Baltic or eastern Europe (e.g., Whooper Swan, Tundra and Taiga Bean Goose), or in an efflux of birds wintering in the Netherlands to the British Isles and Belgium and northern France (e.g., Bewick's Swan, White-fronted Goose). Since there were no severe winters during 1990/91-1994/95 (Fig. 1), goose and swan numbers as well as seasonal patterns and distribution throughout the country reflect the situation in mild winters. The series of mild winters from 1986/87 onwards, eventually may have contributed to increasing numbers of wintering Bewick's Swans and Greylag Geese, whereas numbers of Whooper Swan and Taiga and Tundra Bean Geese have dropped to a lower level as compared to the 1980s.

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