Proceedings of the Vertebrate Pest Conference

On Hawaii Island, within Hawai’i Volcanoes National Park, remnant nesting colonies of Hawaiian petrels, or ‘Ua’u, persisting in subalpine lava flows of Mauna Loa are threatened by feral cats. Trapping has not fully protected these approximately 60 known nests. In some years, cats have killed multiple petrels over the protracted breeding season. To create a core area free from cat predation, the Natural Resources Management Division of Hawai’i Volcanoes National Park, with support from multiple partners, is constructing a 5.5-mile-long barrier fence around the largest known colony. Project planning began in 2009, and fence construction started in 2013. Our design, modified from an Australian fence, is skirted to the substrate at the bottom and rolled over at the top to form a springy, outward-facing arc. Work to date includes finalizing the route, helicoptering in fencing materials and gear to the 9,000+ foot elevation site, pulverizing a narrow work corridor along the fence route (most of it on rough, aa lava), installing approximately 3,900 posts, and attaching visibility marking tape to alert flying petrels. We anticipate needing 1-2 additional work seasons to complete the fence. Ongoing petrel nest monitoring will help us assess response of the colony. Additionally, recently-installed interpretive panels inform park visitors of the conservation needs of this elusive bird.