Annual Variation in Carcass Weight of Norwegian Moose in Relation to Climate along a Latitudinal Gradient

Abstract

Annual variation in carcass weight during the autumn was studied in four Norwegian populations of moose (Alces alces) distributed along a latitudinal gradient (59.degree.N-66.degree.N). In the nothernmost population, mean yearling weights were correlated to mean weight of bulls (2 1/2 years old) and adult cows (.gtoreq. 3 1/2 years). Similarly, the mean weight of the calves was correlated with that of yearlings in the southernmost population. In all but one comparison, a combination of climatic variables explained a significant portion of the annual variation in mean carcass weight. Mean summer temperature, especially the June mean, and summer precipitation were the most important variables. Smaller animals were found in the autumn after a hot rather than a cool summer in the two northern populations. Weather conditions in winter showed little relationship to the annual variation in mean carcass weight. However, a significant relationship was found in the two southern populations, where snow-rich or cold winters were associated with small calves and yearlings in the following autumn.