Research and IPM

Determine the effect of bait density on squirrel foraging behavior.

Determine the optimum baiting area and bait density for delivering a lethal dose of anticoagulants.

Determine the occurrence and extent of non-target bait consumption.

Develop and test a single application baiting strategy for currently registered anticoagulants "that lead(s) to a more judicious use of pesticides".

Using the knowledge obtained through investigating S. beecheyi foraging behavior, a potential alternative control method was developed. Conventional control methods require broad area application of toxicant baits with repeated applications. The developed method required only a single application and represented a significant reduction in both labor and in the quantities of toxicant spread into the environment. While the alternative method did not successfully meet the required level of population reduction (70 percent as established by the Environmental Protection Agency), it did demonstrate that a substantial population reduction could be achieved with significantly less pesticide and application effort. Using the knowledge obtained it is hoped that a method that retains the increased environmental safety can be developed that meets the efficacy needs of those in agriculture.

During the summer of 2002 non-target bait consumption was conducted using surveillance video camera systems placed on the treatment sites. Monitoring was conducted before and after supplementation to determine possible changes in non-target visit rates. No difference was observed between the before and after supplementation. However, it should be noted that this was conducted on sites with single applications. Current use requires a minimum of two applications; this could increase the draw of non-target animals into a baited area.

Preliminary results from 2002 were examined and a potential single feeding strategy was developed. This preliminary strategy was tested on an un-replicated plot in October 2002. Although the single application rate showed efficacious control (approximately 77%) with greatly reduced pesticide use, there were several confounding factors. Results indicate that an effective single feeding strategy may be developed. However, the timing of this application was not optimal. In the next field season more extensive testing of the developed method will be conducted.

The determination of seed acquisition and consumption by ground squirrels will allow the development of a reduced use baiting strategy. To do this we will track the fate of fluorescent-dyed oats dispersed on our plots at various application rates. Testing of the effects of this dye on consumption has been completed and indicates that the dye used, at the treatment concentration, will not affect consumption.

Work also progressed in developing a technique for monitoring oat density. We developed a portable light box with multiple long wave UV lights. With this device, we can easily record oat density in the field. The light box has an opening for the lens of a camera to record the presence of oat groats. The treated oat groats fluoresce under UV light, making oats visible and density easily determined. Field tests of this technique will be conducted in the spring when environmental conditions more resemble those that will be found during testing.

Determination of actual foraging rate and area will commence this spring and summer.