TIME BUDGET OF FEMALE MT. GRAHAM RED SQUIRRELS

Nickie Seto , Dr. John L. Koprowski

TIME BUDGET OF FEMALE MT. GRAHAM RED SQUIRRELS

Allocation of time to daily activities has often been used to elucidate the constraints that organisms face.  For female mammals, lactation is the most energetically costly period.  Time budgets have been observed for male and female Mt. Graham red squirrels (Tamiasciurus hudsonicus grahamensis) at various reproductive stages; however, a comprehensive assessment of how time allocation changes across the period of lactation has not been accomplished.  Time budgets of females at different reproductive stages were compared to one another in order to analyze reproductive female strategies.  Female squirrels (n=13) were located using radio telemetry and their activity and time allocation recorded.  Four reproductive stage categories (non-reproductive, early-lactating, lactating, and late-lactating) were determined via trapping and observation.  Early-lactating and lactating females spent an average of 32.1% more time in nests with young than non-reproductive and 27.3% more than late-lactating females.  Morning nest departure times indicate that lactating females leave the nests later than early-lactating females.  Similarly, early-lactating and lactating females spent less time feeding and foraging than non-reproductive and late-lactating females.  The costs of lactation appear to be a decrease in time spent foraging and suggest a significant energetic trade-off may exist. This research was made possible with help from the Howard Hughes Medical Institute (52006942), the University of Arizona, Mt Graham Red Squirrel Research Project, and USDA Forest Service.

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