The northern Idaho ground squirrel (Urocitellus brunneus) is a small fossorial mammal endemic to central Idaho. The northern Idaho ground squirrel (NIDGS) was listed as a threatened species under the Endangered Species Act (ESA) in April 2000. Mark-recapture is one of the primary methods used to monitor abundance and population trends of NIDGS. Our objective was to determine whether we could make improvements to trapping methods to increase success rates and decrease the amount of time that animals were disturbed by trapping efforts. We compared two methods to improve capture of NIDGS: 1) a polyethylene landscape fabric, and 2) a natural covering (rocks, leaves, or bark). We compared both cover methods associated with two trap types (a Tomahawk trap with a gate trap) to evaluate differences in both trap success rate and time to capture. We predicted NIDGS would enter burrow traps with the fabric cover at a faster rate than with the natural cover because it was more effective at excluding natural light. We believed that NIDGS would see only the light at the end of the trap when covered with fabric and be less inclined to burrow out underneath the trap extension of the gate trap. Furthermore, we believed NIDGS might enter the burrow traps more quickly because of the shade. We believed the fabric might simulate the feeling of safety and seclusion provided by a natural burrow and thus would result in NIDGS more readily and quickly entering into the focal traps.
Results/Conclusions
We evaluated trapping method efficiency based on their deployment time and capture success rates. We used paired t-tests and ANOVA to compare the two trapping methods. We detected no statistical difference in the efficiency of the 2 trapping methods (P > 0.05) and no difference in capture success of NIDGS using either a polyethylene fabric or natural covering over traps.