Predator-proof fencing To combat invasive predators and plants, an eight acre predator-free area (Nihoku) was created at Kilauea Point National Wildlife Refuge in 2014 by constructing a predator-proof fence and removing all mammalian predators from inside of it. The fence is tall enough to prevent animals from jumping over, has a hood to prevent them from climbing, mesh that is small enough even mice can’t squeeze through and has a skirt underground that prevents them from digging in. All of the materials are marine grade stainless steel to ensure it lasts in the harsh coastal environment. Left: Habitat restoration at Nihoku. Right photo: Artificial burrow designed for nesting seabirds Habitat restoration To restore the habitat inside the fence, invasive plants were removed and more than 10,000 native plants representing 30 species have been outplanted to date . Plants were chosen that were not only adapted for the harsh coastal ecosystem but provided food for Nene and cover for nesting seabirds. Each year one acre is restored so that over time, the entire enclosure will ultimately be comprised of native plants. To encourage seabirds to nest in the area, 50 artificial burrows were installed to provide nesting habitat for the seabirds. Below: video on habitat restoration at Nihoku
Below: video describing seabird artificial burrows put in at Nihoku
Seabird social attraction and translocation The final phase of the Nihoku Ecosystem Restoration Project has been translocating and attracting threatened seabirds (Newell's Shearwater and Hawaiian Petrels) into the area. This is done in two ways- social attraction relies on broadcasting their calls from two large speakers to ‘call them in’ and encourage adult birds to nest. Second, chicks that have not yet left their burrows in the mountain colonies are translocated to the site, and cared for at Nihoku until they fly out to sea for the first time. By choosing chicks who have not yet emerged from their mountain burrows, we ensure that they imprint on Nihoku by observing the night sky there. In 3-5 years we expect the first translocated chicks to return to Nihoku and breed as adults. The first Hawaiian Petrel chicks were translocated to the site in 2015, and the first Newell's Shearwater chicks were moved in 2016; we hope to do at least five years of translocations of each species.
Left: Newell's Shearwater chick in pet carrier being removed from it's mountain burrow on translocation day Right: Newly translocated Hawaiian Petrel chicks at Nihoku Managing mountain colonies and finding chicks for translocation Over the last five years, a number of known colonies have been considered as potential source colonies for translocation. Using a range of criteria, up to seven colonies were selected. These colonies are monitored extensively each year. Burrows in these colonies have been located (though a combination of nocturnal auditory surveys and active searching) and are then monitored using cameras and burrow checks to assess the suitability of chicks for translocation. At the same time, extensive predator control operations are undertaken in these colonies to protect the chicks from being eaten by introduced predators such as cats and rats. A few weeks before natural fledging, a cohort of chicks that have not yet left their burrows in the mountain colonies are translocated to the site.