COMPARISON OF TRAP-CATCH AND BAIT INTERFERENCE METHODS FOR ESTIMATING POSSUM DENSITIES

摘要

Leg-hold trapping is a standard method for estimating possum population densities in New Zealand. However, the method is costly because traps are heavy and bulky and by law are required to be checked daily. This limits the number of sampling lines that can be used, which reduces precision. Traps also threaten rare native ground-birds. We evaluated two lightweight alternatives that are more cost-effective to use, orange quarters and WaxTags~(R). WaxTags~(R) are wax-blocks on a plastic tag and are marketed specifically for possum and rat population monitoring. Results showed that both the orange quarters and WaxTags~(R) were more effective for indicating the presence of possums than leg-hold traps. WaxTags~(R) were considered the better of the two alternatives because they did not attract more possums through time which can confound density estimates. Observers also indicated that possum bite-marks were easier to identify on the WaxTags~(R) than orange quarters.