Proulx: The 2010 Richardson's Ground Squirrel Research and Control Program

Date: January 2011
Term: 1 year
Status: Completed
Researcher(s): Gilbert Proulx, Alpha Wildlife Research and Management Ltd, SK
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: SARM, SPG, CAAP

Project Summary

Previous research conducted from the 2007 to 2009 by the Richardson’s Ground Squirrel (RGS) (RGS; Spermophilus richardsonii) Research Program in search of effective and socially acceptable toxicants, has provided a greater understanding of ground squirrel populations and control methods. In 2010, a new study was carried out in southern Saskatchewan with the objectives of testing various attractants, toxicants and bait station designs to determine their control efficacy. Overall, the differences observed in control efficacy suggest that Richardson’s ground squirrels are less receptive to man-made baits when natural food is abundant, and that the acceptability of strychnine baits varies between populations and seasons. Researchers recommend that more work should be invested in attractants, and that strychnine baits be studied and improved to be effective under different environmental conditions.

Previous research conducted from the 2007 to 2009 by the Richardson’s Ground Squirrel (RGS) (RGS; Spermophilus richardsonii) Research Program in search of effective and socially acceptable toxicants, has provided a greater understanding of ground squirrel populations and control methods. Researchers demonstrated that fresh strychnine baits could be used in multi-capture (pen) traps to control ground squirrels while minimizing risks of non-target and secondary priorities.

In 2010, a new study, led by the Alpha Wildlife Research and Management Ltd., was carried out in grasslands and pure or mixed alfalfa fields in southern Saskatchewan near Hazenmore with the objectives of testing various attractants, toxicants and bait station designs to determine their control efficacy. Three attractants with the potential of increasing capture efficiency were tested: peanut oil, vanilla extract and linoleic acid (a component of canola and sunflower oil) and several strychnine baits or toxicants were tested. In addition, three types of bait stations and pen traps were tested.

The results showed that peanut or canola-sunflower oils attracted ground squirrels, but the vanilla extract did not. Although the control levels were similar among most of the strychnine baits, from a biological point of view, the strychnine-treated oats with salt and mineral mix was the most effective formula and was the only strychnine bait to control 70% of all animals in both study plots where it was applied. Strychnine baits with corn syrup had the highest and lowest control values, this pointing out a large variation in the acceptation of baits by ground squirrels. Baits with salt and mineral mix were more effective than all other baits, followed by baits with sunflower and canola oils, and Nu-Gro and Maxim baits with and without peanut butter.

Overall, the differences observed in control efficacy from 2008 (drought year) to 2010 (wet year), and between spring and summer 2010, suggest that Richardson’s ground squirrels are less receptive to man-made baits when natural food is abundant, and that the acceptability of strychnine baits varies between populations and seasons. The 2010 study showed that oils were particularly attractive to ground squirrels. Adding different oils to different grain types, some already rich in natural oils, could lead to the development of more attractive baits. Researchers recommend that more work should be invested in attractants, and that strychnine baits be studied and improved to be effective under different environmental conditions.

The results of the bait stations control varied greatly among treatments, but the highest control occurred in a study plot where baits had been placed in burrow openings. The Bell box bait stations were superior to Inverted T bait stations. These pre-filled boxes were easy to handle, did not require any special anchor and were less likely to impact non-target species. The pen traps had limited success, and the results showed that pen trap doors should be modified to eliminate escapes. Researchers recommend further work should be conducted on the development and testing of multi-capture pen traps.

Figure 1. Comparison of the efficacy of various strychnine baits to control Richardson’s ground squirrels. Treatments within a same group had similar (P>0.05) mean control levels.

Figure 2. Richardson’s ground squirrels feeding at an Inverted T and Bell box bait stations.

Full Report PDF: The 2010 Richardson's Ground Squirrel Research and Control Program