WOLF PREDATION ON MOOSE - A CASE STUDY USING HUNTER OBSERVATIONS

Abstract

We studied predation by colonizing wolves on a high density and highly productive moose (Alces alces) population in south-eastern Norway (about 1.5 moose and 0.01 wolves per km² in winter). As indices to population changes, we used hunter observations. Over the summer, the wolf pack utilized about one tenth of their total territory (530 km²), with the den area as the centre of activity. Of the main prey taken (moose, roe deer, and beaver), moose calves contributed 61% of the biomass ingested by wolves in summer. Hunting statistics and hunters’ observations of moose showed no changes for the territory as a whole after wolves settled there in 1998. However, in the den areas (60 - 80 km²) the number of calves per cow and the total number of moose seen per hunter-day significantly decreased during the year of wolf reproduction. The following year, though, both indices increased again. We speculate that some of the lack of overall effects might be due to increased fecundity in cows that lost their calf. As the wolves changed their den from year to year, den areas were spatially spread over time. The pressure from wolf predation will differ between cohorts in the same area, and landowners should adjust their hunting quotas accordingly.