Diet and dispersal of Barnacle geese on Spitsbergen: the advantage of being first

Geese fly from their wintering grounds in the temperate climate zone to the arctic to breed. They are faced with a decrease in the quality of their food plants. Directly after snowmelt the protein content is highest and shows a sharp decline afterwards. The quantity of foodplants also shows a sharp decline during the short summer, due to grazing by geese and due to natural leaf death. In this research is illustrated that there are big changes in the diet of geese during the season, and there are big differences in the diet (and diet changes) between different areas. Geese show shifts in their habitat use during the season. There are marked changes between the dispersal of non breeders and families. Family birds disperse much more than non breeders. The family birds leave the heavily grazed areas and go to feed on areas with a higher biomass of graminoids. In this way their diet can contain more of the preferred graminoids. They first start to feed on save places close to water near the village and later move towards the fast tundra area. Early and late hatched families show the same distribution pattern during the season. The difference is that the early families are always the first ones to arrive in a certain area. So the early families have an advantage in the availability of food they encounter, and are able to have a higher proportion of preferred food plants in their diet.