Monitoring Eradication of European Mouflon Sheep from the Kahuku Unit of Hawai‘i Volcanoes National Park

Eradicating invasive European mouflon sheep from the Kahuku Unit of Hawai‘i Volcanoes National Park required a 15-year, multi-method approach that demonstrated significant challenges in scaling up ungulate control efforts. Despite initial success with aerial and ground-based removals—totaling 4,868 animals, including 261 from aerial shooting—efforts intensified dramatically in the final years, with the removal of each remaining animal requiring nearly 15 times more effort by 2013–2016. The study highlights that while ground-based methods (e.g., shooting with dogs) were most effective for large-scale removals, techniques like baiting and trapping proved ineffective for detecting small, isolated groups. Complementary active and passive monitoring, including camera traps and forward-looking infrared (FLIR)-assisted surveys, were critical in tracking the population's decline and pinpointing remaining individuals. The research underscores the logistical and operational complexities of eradicating invasive ungulates from unenclosed areas.

Judge, S. W., Hess, S. C., Faford, J. K., Pacheco, D., & Leopold, C. R. (2017). Monitoring Eradication of European Mouflon Sheep from the Kahuku Unit of Hawai‘i Volcanoes National Park. Pacific Science, 71(4), 425–436. https://doi.org/10.2984/71.4.3