EFFECTS OF PREY SIZE, MEAL SIZE, MEAL COMPOSITION, AND DAILY FREQUENCY OF FEEDING ON THE RECOVERY OF RODENT REMAINS FROM CARNIVORE SEATS

Recovery of rodent bone and teeth from coyote (Canis latrans) scats (f eces) varied with prey size, meal size, energy content of the meal, an d the frequency with which prey were consumed. Mean percentages of mou se and rat teeth recovered ranged from 1% (SE = 0.5%, n = 5) to 24.4% (SE = 3.6%, n = 4) and from 13.8% (SE = 3.8%, n = 5) to 52.5% (SE = 16 .6%, n = 5), respectively. A significant portion of this variation res ulted from physiological mechanisms affecting how long prey were retai ned in the digestive acids of the stomach. Recovery of hair did not va ry and thus it was considered to be nondigestible. Owing to the variat ion in the recovery of bone and teeth and the lack of variation in the recovery of hair, we recommend the use of teeth or bone to identify t he small rodents present in carnivore seats, and then the use of a vis ual estimate of hair, or sample of hair, to apportion the seat to the prey items present. We caution against using the numbers of teeth or d iagnostic bones to determine the number or amount of a prey item repre sented by a seat without addressing the variability in their recovery. The effects of gastrointestinal physiology should be considered when planning feeding trials to derive correction factors for seat analysis .