Research has revealed alarming rates of decline for Hawai’i-endemic seabirds, but conservation efforts are building momentum and offer hope for these threatened species.
By: André Raine
Kaua’i’s endangered seabirds are facing catastrophic declines, as our new paper in the journal Condor shows. Using data from radar surveys conducted between 1993 and 2013, we found that the Endangered Newell’s Shearwater (Puffinus newelli) declined by 94% in this two decade period, and the Vulnerable Hawaiian Petrel (Pterodroma sandwichensis) by 78%. Both are staggering rates of decline for these two Hawai’i–endemic seabird species, and shows just how perilous their positions currently are.
Kaua’i is a vital last refuge for the two species—it holds 90% of the world population of the Newell’s Shearwater and large colonies of the Hawaiian Petrel. The two species are now mainly confined to the island’s lush and forested interior–wet montane forests carpeted with Uluhe Fern and moss-covered ʻŌhiʻa trees. The fossil record shows us that the Newell’s Shearwater and Hawaiian Petrel once bred across the island (and indeed across the Hawaiian island chain), but they have been steadily pushed back into remote forested areas over the centuries, leaving behind a trail of abandoned “ghost colonies” where thriving seabird colonies once existed.
Kaua’i is a vital last refuge for the two species—it holds 90% of the world population of the Newell’s Shearwater and large colonies of the Hawaiian Petrel.
What is the cause of this decline? Like seabirds around the world, they face a whole raft of issues. In the mountains they are dragged out of their burrows and eaten by introduced feral cats, rats and feral pigs, while the native forests around them are taken over by introduced plants, such as Strawberry Guava. Adult birds flying to and from their colonies collide with powerlines that almost entirely circle the island, and fledglings leaving their burrows for the first time are drawn into lights around the coast and become grounded. Then there are threats at sea, poorly understood but likely to include the effects of climate change and over-fishing.
Sounds pretty bleak, right? Well, although the story is a grim one, I also sense that we are at a turning point for these species; conservation work for seabirds on Kaua’i is at an all-time peak. Several colonies are now being protected through seabird management projects–in areas such as Upper Limahuli Preserve and the Hono o Nā Pali Natural Area Reserve. Dedicated teams spend long, wet, and muddy weeks in these areas monitoring the birds and removing introduced predators. We are working with the local utility company to try to prevent powerline collisions, including trialling innovative new techniques such as laser fences to divert birds up and over particularly bad stretches of power line. A translocation project involving multiple organisations is underway to move birds from montane colonies to a predator-proof fenced site called Nihoku, in the hopes of establishing a highly protected colony in this area. And a large, multi-entity Kaua’i Seabird Habitat Conservation Plan is in the works to mitigate for the effects of light attraction.
Although the story is a grim one, I also sense that we are at a turning point for these species.
There is still time–all hope is not lost. But as our paper has shown, we need to take action now, and we need to do so quickly. For species that were once so numerous that they darkened the skies of the island as they passed overhead, we are currently approaching the tail end of their story. We need to ensure there is a new chapter.
Featured photo: André Raine with an Endangered Newell’s Shearwater. Credit: Colleen Suttner