SEASONAL AND CIRCADIAN ACTIVITY PATTERNS OF FEMALE FISHERS, MARTES PENNANTI, WITH KITS

To assess factors that may influence reproductive success of Fishers ( Martes pennanti), we investigated the effects of kit development and l itter size on circadian pattern and levels of activity (proportion of locations classified as active) of four radio-collared females with ki ts in southcentral Maine during the March-June denning period in 1988, and two of these four females in 1989. Activity levels varied greatly among individuals (P = 0.0057). A significant interaction between cir cadian and developmental periods (P = 0.025) indicated that the circad ian pattern of activity changed after young were weaned. Females carin g for weaned offspring showed more diurnal activity, suggesting increa sed energetic costs because of foraging. The activity level during kit rearing did not increase significantly with litter size (P > 0.08).