Studies of Artificial Light, Seabird Fallout, and Habitat Suitability Concerning Newell's Shearwater and Hawaiian Petrel Conservation
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The federally threatened Newell’s Shearwater (Puffinus newelli; listed as endangered on the IUCN Red List) and endangered Hawaiian Petrel (Pterodroma sandwichensis) formerly nested throughout the main islands of the Hawaiian Archipelago. As a result of anthropogenic threats, breeding ranges of these species are now restricted to high-elevation regions of particular islands and numbers of Newell’s Shearwaters are currently declining. I conducted large-scale GIS-based studies of artificial light, seabird fallout, and habitat suitability concerning the conservation of these two seabirds. Models that I developed suggest that there are few to no portions of Kauai from which young birds could fledge and not view light on their post-natal nocturnal flights. Additionally, the spatial pattern of observed Newell’s Shearwater fallout is consistent with the amount of light that fledglings may view along their first flights to and beyond the coastline, providing support for the idea that fledglings could be attracted back to land after reaching the ocean in numbers large enough to contribute significantly to island-wide fallout. Terrestrial habitat suitability models for both species on Kauai predict that a large portion of the interior of Kauai could be suitable for both of these species in the absence of anthropogenic threats. Habitat suitability models incorporating threats identified the mountains on the north-central portion of the island as the most isolated from a combination of anthropogenic disturbances, making it ideal for future surveys. Much of this region, however, is privately owned and not currently designated as a reserve. In addition, a moderate degree of overlap between habitat predicted to be suitable for both the Hawaiian Petrel and Newell’s Shearwater suggests that some of the same larger tracts of land could potentially be managed jointly for both species. These studies provide information that is crucial for conservation biologists, federal and state employees, and private landowners because expanding efforts to further reduce artificial light output and control non-native predators, as well as management of additional lands as reserves, may be necessary for the protection and preservation of these two endemic tropical seabirds.