Monitoring and Control of Feral Cats on Kaho`olawe: One Step Towards Eradication

The island of Kaho`olawe provides an extraordinary opportunity for conservation and has been referred to in numerous recovery plans for declining populations of Hawaiian avifauna. The feral cat is widely recognized as one of world’s most destructive invasive species and has been implicated in the decline or extinction in a number of native avian species. Of the main 8 Hawaiian Islands, Kaho’olawe presents the most feasible option to eradicate feral cats due to its limited access, remoteness, relatively small size (116 km2), and reserve status. With assistance from a U.S. Fish and Wildlife Service grant, the Kaho`olawe Island Reserve Commission restoration program monitored and controlled feral cats from November 2008 to February 2011. Monitoring techniques included camera traps, tracking stations, spotlight surveys, trapping, and diet and disease analysis. Feral cat density was estimated to be high based on a capture rate and regular monitoring surveys. Cat track observations declined significantly (P < 0.001) during the course of the study. Twenty-two of 46 (47.8%) cats tested positive for seroprevalence to the parasitic protozoan Toxoplasmosis gondii. A major component of prey items consisted of invertebrates mainly comprising centipedes and intertidal crabs. With cooperation from Island Conservation, information gathered helped create an implementation plan for the eradication of feral cats on Kaho`olawe