LIHUE — Two of Kauai’s endangered seabird species are in peril, according to a study released Wednesday by the Kauai Endangered Seabird Recovery Project.
The study shows between 1993 and 2013, populations of the ‘a’o (Newell’s Shearwater) declined by 94 percent and ua’u (Hawaiian Petrel) declined by 78 percent.
“The results of this study demonstrate just how poorly these two iconic birds have fared on Kauai over that time period,” said Andre Raine, lead author of the paper.
And the fate of these bird species indicates a more systemic problem, said kumu Sabra Kauka.
“To me it’s an indicator of the health of Earth both on land and on sea,” she said. “Is the sea able to produce the food that these birds need to live? Is the land safe for them to raise their young?”
The majority of the radar sites showed massive decreases in numbers of the birds over the years, adding up to a “rapid downward trajectory” Raine said, particularly in the south and east of the island.
The North Shore hasn’t escaped the trends, however. Kauka said she found two dead shearwater birds at Nu’alolo Kai during a maintenance project with Ohana over Memorial Day weekend.
She took photos, but didn’t send the carcasses over to Raine.
“One was banded so I’ll get that band number to him and it’ll tell us where it came from,” she said.
It is still early in the nesting season, but Kauka said she didn’t see as many seabirds nesting in the cliffs, either.
“I only heard a few of them this year and not right above where we camped,” Kauka said.
The study used truck-mounted radar at 15 standard sites around the island. Radar surveys at these sites were started in 1993 by Robert Day and Brian Cooper of ABR Inc., and were continued near-annually by KESRP from 2006 onwards.
Radar is utilized worldwide to study birds and is a key tool to monitor the island’s seabirds as they fly overhead in darkness to and from their breeding colonies and the sea. The radar allows observers to “see” the birds flying overhead in the darkness as a series of dots passing across the radar screen.
By assessing the speed of movement, the direction of travel, and the time that the event is recorded, birds are identified to their respective species.
The study highlights just how critical recent conservation initiatives are for the species on Kauai in order to have a hope of reversing the situation, Raine said.
“Kauai holds 90 percent of the world’s population of ‘a‘o and a significant proportion of the world’s population of ua‘u, so it is vital that we protect these birds,” Raine said.
He continued: “Recent conservation initiatives on the island from a wide range of different organizations, land-owners and entities have shown that people are become more and more aware of the perilous state of these birds. This gives me hope that we can reverse these spiraling trends.”
Some of the threats to the species are feral cats and other introduced predators, powerline collisions, light attraction and invasive plants. Sea-based threats include overfishing, by-catch and the effects of climate change, according to the state Department of Land and Natural Resources.
A predator-proof haven for the endangered seabirds has been created at Nihoku at the Kilauea Point National Wildlife Refuge and since 2015, 30 ua’u have been transferred there by staff members from various state and federal agencies, as well as Lindsay Young from Pacific Rim Conservation. The group has translocated eight ‘a’o into the enclosure in the beginning of 2016.
But, translocation into a single predator-free area is only one tool that is being used to achieve recovery for these species, according to Young.
“Protection of their existing breeding colonies in their mountain habitats through fencing and predator control and removal is extremely important in the long term survival of the species,” she said.
Radar work will continue on Kauai until mid-July.
“The decline is significant because they (‘a’o and ua’u) have always been an indicator of the condition of our environment,” Kauka said. “Traditionally, they’ve directed the fishermen to schools of fish.”