Live trapping small mammals can inform us about the community structure in disturbed and restored habitats while providing exciting educational opportunities for future managers and conservationists. Unfortunately, trap mortality and low trap success can reduce the scientific value of these excursions and negatively impact the student experience. Increasing the frequency of trap checks has been shown to reduce mortality for some trap types and species, but the additional disturbance associated with these checks may discourage animals from approaching and entering traps. I was interested in how increasing the frequency of trap checks during an undergraduate summer field course would affect trapping outcomes. In June 2016, 2018, and 2019, students and I trapped small mammals using Sherman XLK traps at Hunt Hill Audubon Sanctuary near Sarona, Wisconsin. We trapped in a remnant prairie and a nearby old field that was intermittently grazed. In 2016 and 2018, we checked traps twice a day. In 2019, we checked traps three times a day.
Results/Conclusions
We had a total of 134 captures over 1944 trap-nights across the three sessions. The average number of captures at each trap check was 11.0 in 2016, 2.0 in 2018, and 2.7 in 2019. The higher number of captures in 2016 was most likely due to higher rainfall during the 2016 trapping session. Weather conditions were similar in 2018 and 2019, and we found similar numbers of animals each time we checked traps. The overall trap mortality rate was 0.052 (0.023, 0.109), and it did not depend on the frequency of trap checks (p = 0.653, Fisher’s Exact Test). These preliminary results suggest that increasing from two to three trap checks a day is unlikely to reduce the number of dead animals that students find in traps, although it also does not appear to deter animals from entering traps. During June 2020, I plan to run both schedules simultaneously on comparable grids to reduce the confounding effects of differences among the years.