FOOD-HABITS AND OBSERVATIONS OF THE HUNTING BEHAVIOR OF ARCTIC FOXES, ALOPEX-LAGOPUS, IN SVALBARD

Food habits of Arctic Foxes in Svalbard were determined by examining 898 stomachs from trapped foxes, by recording prey remains outside dens and by observing feeding and hunting behaviour in the field. Sixty percent of the stomachs contained food. Reindeer (Rangifer tarandus) was the most frequently encountered food item (41%) followed by Rock Ptarmigan (Lagopus mutus) (30%) and sea birds/fulmar (Fulmarus glacialis) (35%). Several other food items were found in the stomachs, supporting the general perception of the Arctic Fox as an opportunistic feeder and scavenger. The weights of different food items in stomachs generally reflected their frequency of occurrence. There were no differences in food habits between sexes, between juveniles and adults, or between seasons. Reindeer, ptarmigan, alcids, fulmars and geese were the most frequently found prey remains at dens. Prey remains from terrestrial species (Reindeer, ptarmigan) were recorded significantly more often at inland dens (>10 km from the coast) than at coastal dens. Remains from Reindeer calves (< 4 months old) were found at several dens, and one adult fox was observed killing a Reindeer calf. Arctic Foxes also preyed heavily on breeding geese. Barnacle Geese (Branta leucopsis) did not protect themselves as well as Pink-Foot Geese (Anser brachyrhynchus). Arctic Foxes in Svalbard are both skilled predators and scavengers, and they are typical opportunistic and generalistic feeders. Fluctuations in the mortality of Reindeer and in the density of ptarmigan may affect Arctic Fox numbers in Svalbard.