Masters Thesis

Daily activity patterns of mountain lions (Puma concolor) in relation to the activity of their prey species in southern Arizona

Food resources are not evenly distributed over space or time, and therefore, changes in prey abundance and availability may influence predator behavior both spatially and temporally. It has been suggested that mountain lions (Puma concolor) follow the daily activity patterns of their main prey species. In the Sonoran Desert the javelina (Pecari tajacu) is an important prey item for mountain lions and it has been shown that javelina shift from a diurnal activity pattern during winter months to a nocturnal pattern in the summer. I examined whether mountain lions shift their activity patterns between summer and winter following the activity of the javelina. Alternatively, I examined whether mountain lions shifted their diet to other species that were more active during the period when mountain lions were active. I analyzed 117 mountain lion fecal samples to determine their diet during summer (16 April–15 October) and winter (16 October–15 April) and I used the date/time stamps from 4,528 trail-camera photographs collected during March 2001-September 2006 in southern Arizona to index daily activity patterns of mountain lions and their prey species. Mountain lions did not track the activity of one particular prey species, but appeared to shift their daily activity patterns and diet according to temperature and availability of different prey species in a given season. Coues white-tailed deer (Odocoileus virginianus couesi) were the most common prey in both winter and summer, but the mountain lion diet was supplemented with seasonally abundant and vulnerable domestic calves (Bos taurus) in summer and javelina in winter. Because mountain lion activity patterns and their diet both changed between winter and summer, it was difficult to discern exactly what drove these seasonal shifts. High temperatures may have influenced mountain lions to shift towards nocturnal activity in the summer. Coues white-tailed deer remained primarily diurnal through the summer, while the excessive daytime temperatures may have limited mountain lion movements and reduced their ability to exploit this resource. The occurrence of deer in mountain lion diet decreased in summer, and cattle increased. With the cooler daytime temperatures and the absence of calves of domestic cattle in the winter, mountain lions became more diurnal, which coincided with the activity of Coues white-tailed deer and javelina, both of which became more prevalent in the mountain lion diet at that time.

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