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 litter size on circadian pattern and levels of activity (proportion of locations classified as active) of four radio-collared females with kits 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. A significant interaction between circadian and developmental periods indicated that the circadian pattern of activity changed after young were weaned. Females caring for weaned offspring showed more diurnal activity, suggesting increased energetic costs because of foraging. The activity level during kit rearing did not increase significantly with litter size.