The Ecology Of Marten In Southcentral Alaska

Abstract

The ecology of marten in the upper Susitna Basin, southcentral Alaska was studied from January 1980 to June 1982. Data were gathered on home range and movements, seasonal food habits, habitat use and winter energetic strategies. Radio telemetry was used to obtain a total of 560 locations for 17 marten. Mean home range sizes of marten along the Susitna River were 3.71 km('2) for females, 6.82 km('2) for males and 6.75 km('2) for adult males (2+ years). Marten were found to be nocturnal in autumn and to show strong variability in their diel activity patterns in late winter. Marten tended to move upward in elevation during spring and downward in autumn, contrary to the prevailing views of trappers. Analyses of marten scats and colon contents collected during four seasons showed the most important foods to be microtine rodents, squirrels, fruits and birds. Major foods showed strong seasonal variation in utilization. Microtines were most important in autumn and showed declining use over winter. Northern red-backed voles were the most important microtine species. Sciurids were most important in spring and appeared to be a nonpreferred alternative food. Marten made little use of shrews, snowshoe hares, porcupines or insects. Carrion and human foods were highly preferred and consumed when available. Habitat utilization was studied through the use of aerial transects and snow tracking and by identifying resting sites. Marten foraged for microtines more frequently than expected in vegetation types dominated by black spruce. Marten rested in winter primarily in active red squirrel middens in stands dominated by old-growth white spruce. Fat depot and organ weights and total body fat of marten were measured to find an indicator to total body fat. Marten were found to have extremely low body fat ratios which did not show a significant change over winter.