San Nicolas Island supports the densest and perhaps most stable population of island foxes. In fact, it is the only population not known to have experienced a sudden and dramatic decline in recent years. The health of the San Nicolas Island fox population contrasts starkly with those from Catalina Island, where disease nearly caused the extinction of the local subspecies, and the northern Channel Islands (Santa Cruz, Santa Rosa, and San Miguel islands) where a novel predator, golden eagles, decimated local populations. We are developing methods, in cooperation with the U.S. Navy and funded by the Department of Defense Legacy Resource Management Program, to monitor island foxes on San Nicolas Island to ensure that novel diseases or predators do not decimate this population.

The primary goal of this project is to efficiently monitor a large sample of foxes using newly developed radio-telemetry techniques. Special collars and remote receivers designed by Communications Specialists, Inc. allow a single IWS biologist to conduct daily mortality checks on 60 animals. In addition to monitoring the survival of over 60 animals on San Nicolas Island, we are collecting data on food resources and habitat use by foxes in collaboration with researchers at (Brian Cypher) and San Francisco State University (Robyn Powers). The data collected during this study will be used to design criteria triggering specific management actions to mitigate the introduction of a novel disease or predator to San Nicolas Island and reduce the risk that this subspecies ever has to join the four island fox subspecies already listed under the Endangered Species Act.