Hunter observations as an index of moose Alces alces population parameters

The accuracy of hunter observations (moose seen per hunter day) as a source for various population parameters in moose Alces alces L was evaluated. We found an overall positive correlation between density and observation inde x. The strength of the relationship was similar in all of the three countie s studied. The observation index levelled off with increasing density (>1.0 moose/km(2)). Sightability of moose differed significantly among two of th e three counties studied which makes comparisons between the regions diffic ult. However, adjusting the regional observation index by independent estim ates of population size enables comparisons over larger areas. We found a p robability of 0.81 that a change in observation index also reflects the dir ection of a change in population size. The reproductive rate calculated fro m hunter observations (Sigma calves)/(Sigma females) was correlated with th e observed mean recorded reproductive rate among radio-collared moose in a county. Furthermore, moose reproduction as estimated from hunter observatio ns was positively correlated among counties in northern Sweden indicating l arge-scale synchrony. Our findings indicate that hunter observations of moo se reflect moose population size and reproductive rate reasonably well, and can be used to monitor population fluctuations. If calibrated, one may use observation indices for estimates of population size in local moose manage ment as an alternative or supplement to more costly monitoring methods. If not calibrated, observational data may be misleading if they are used as a density indicator.