Pest Control Research developed the patented peanut butter WaxTag (NZ Patent 516900) to detect rodents on offshore islands. WaxTags are a plastic tag that contain a lump of non-toxic wax. The rats are attracted to the peanut butter smell in the wax and bite it to determine if it is palatable. The resulting bite-marks allow the animal that bit the tag to be identified. Animals that commonly bite the tags are mice, rats and hedge hogs. For identification of bitemarks click on the following link
In New Zealand the Department of Conservation has sucessfully eradicated rodents from islands resulting in a dramatic increase in birdlife. However rats can be reintroduced onto islands from visiting boats or they can swim from the mainland or other island if they are close enough. Research has shown that the peanut butter WaxTags will detect the presence of reinvading rats indicating that rodent control measures need to be used. For research results regarding WaxTag use on islands click on the following links.
Peanut butter Waxtags have also been shown to be effective for the detection of mice when compared to tracking tunnels. For the reserach paper regarding this research click on the following link http://newzealandecology.org/nzje/3069.pdf. Peanut butter WaxTags have also been shown to be a ggod device for estimating the density of rats and mice in wetlands. Click on the following link for a presentation describing the results of this research. http://www.sanctuariesnz.org/meetings/documents/Gillies2016.pdf