COS 280-4 - Activity Patterns of Fox Squirrels Sciurus niger and American Red Squirrels Tamiasciurus hudsonicus Based on Camera Traps

Background/Question/Methods

North American red squirrels (Tamiasciurus hudsonicus) and fox squirrels (Sciurus niger) are prevalent throughout the northern United States and along southern Canada. Both species are believed to be diurnal with a unimodal to bimodal activity pattern and variable activity duration depending on season and latitude. However, the fox squirrel was also shown to exhibit substantial individual variation in both activity duration and pattern. Our first objective was to verify if camera trapping can describe and contrast activity patterns between species and seasons. Our second goal was to compare activity patterns of individual fox squirrels. We established four camera traps, each facing a tree-mounted feeding platform from 1-2 meters away. Four individual fox squirrels were tagged using differently colored neck collars. For each picture, we recorded date/time, species, and collar color. For some analyses, we only included first/last daily frames as indicators for the onsets and offsets of the activity phase and determined the activity durations as the time difference between first and last frames. The statistical significance of the timing and differences between species and seasons were tested using circular statistics while differences in the activity duration were examined using a two-way ANOVA, both at p-levels below 0.05.

Results/Conclusions

In the first year of this ongoing study, we recorded 1,460 trapping days, totaling 350 first/last frames for fox squirrels but only 126 first/last frames for red squirrels as the species was almost absent in the winter and spring of 2020/21. In summer, first and last frames taken were almost indifferent between the two species and occurred at about 7:20 and 16:10 ET, respectively, whereas in the fall, first frames of fox squirrels were taken about an hour later than red squirrels (8:35) and last frames were taken about an hour earlier than red squirrels (14:57). First frames for fox squirrels were taken significantly earlier during the spring and summer as compared to fall (+1 hour) and winter (+2 hours), whereas last frames occurred significantly earlier in fall and winter (-2 hours) compared to spring and summer. Individual fox squirrels showed significantly different timing and activity durations compared between each other and the unmarked population. The duration of the activity phase was significantly influenced by species, season, and their interaction. Our results compare well to the findings of other studies using more laborious, expensive, or obstructive methods suggesting that camera trapping should be more commonly used in chronoecological research.