Constructing a Predator Exclusionary Fence to Protect Hawaiian Petrels (Pterodroma sandwichensis) at Hawai῾i Volcanoes National Park

Abstract

Remnant nesting colonies of endangered Hawaiian Petrels, or ‘Ua’u (Pterodroma sandwichensis), on Mauna Loa, Hawai’i Island, are primarily threatened by feral cats. At Hawai῾i Volcanoes National Park, trapping success has been variable due several challenges, including the difficulty of accessing remote, subalpine (9,000’) sites. To create a core area free from cat predation, the park, with support from multiple partners, constructed a five mile barrier fence encircling 640 acres of the richest known concentration of subalpine Hawaiian Petrel nests on Mauna Loa. We report on key fence design elements, pilot studies, step by step construction details, concurrent and subsequent monitoring, and lessons learned throughout the project for the benefit of other managers considering exclusionary fencing.