Ardea
Official journal of the Netherlands Ornithologists' Union

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Meire P. & Kuijken E. (1991) Factors affecting the number and distribution of wintering geese and some implications for their conservation in Flanders, Belgium. ARDEA 79 (2): 143-157
The Oostkustpolders in the NW part of Flanders is an important wintering haunt for Pinkfooted and White-fronted Geese. Their numbers, distribution and behaviour have been studied for nearly 30 years. The numbers of Pinkfeet have been increasing gradually in our study area, whereas the numbers of Whitefronts have mainly increased after the three severe winters 1984/85 - 1986/87. In severe winters there is always a large influx of birds of both species. Pinkfeet arrive in early November and there is a tendency to arrive earlier in recent years. Numbers peak at the end of December. Whitefronts arrive in mid November and peak in the first half of January. By the end of February most geese leave the Oostkustpolders. Over the years the geese dispersed from the core feeding area near Damme to the surrounding polders. This dispersion came about by a shooting ban and the influx of large numbers of birds during severe winters. Within winters, birds disperse over the whole polder area. They seem to follow a pattern of cyclic grazing different parts of the polder. Based on behavioural observations it can be shown that the dispersal occurs when feeding conditions deteriorate due to decreasing grass length. In this way all polders are grazed to a certain extent after which the whole cycle can start again. Although there are clear indications that at some times the maximum number of geese feeding in an area may be reached, the cumulative number of goose-days varies greatly between complexes. No relation is found however with the amount of food but a significant negative correlation is found between the number of goose-days per complex and the time of first arrival in that complex. The density of geese is found to be similar between all the polder complexes studied. The changes in the population of both Pinkfeet and Whitefronts are discussed and the factors influencing the occurrence of geese in the Oostkustpolders and the carrying capacity of the polders are analysed. Finally two contrasting views on goose protection, concentrating versus dispersing the geese, are discussed.


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