An endangered native bird has been found on Maunakea for the first time in nearly 70 years.
University of Hawaii at Hilo researchers announced Thursday that they located an ‘ua‘u — a seabird also called the Hawaiian petrel — at a nesting site on Maunakea in May, the first time one has been recorded on the mauna since 1954.
The ‘ua‘u is a federally endangered species mostly found around the Haleakala crater on Maui, but other populations exist on other islands.
On the Big Island, the species largely nest on Mauna Loa. Only 50 or 60 breeding pairs are believed to remain on the island, according to the National Park Service.
Researchers first detected the Maunakea ‘ua‘u using sound recorders and thermal imagery in April on land managed by the Department of Hawaiian Home Lands. DHHL staff then discovered a burrow and set traps around the site to deter predators such as cats and mongooses.
UH-Hilo researcher Patrick Hart said the burrow likely is home to a breeding pair of ‘ua‘u. The male and female take turns incubating a single egg while the other flies to the sea for sustenance. Because of this, he said, the birds are difficult to detect.
“They come in after dark, and they leave before sunrise,” Hart said, adding that the bird’s numbers have dwindled substantially over the years because of human interference as well as the introduction of cats, which are invasive predators.
Based on the bird’s behavior, Hart said he and other researchers assume an egg is in the burrow. ‘Ua‘u eggs incubate over 60 days, and then the hatchling takes another several months before it’s ready to leave the nest and fly on its own.
Eventually, however, the ‘ua‘u will return to the burrow if they can, Hart said — the birds typically return to where they were born to breed.
Because of this, Hart said the discovery probably does not indicate a rebounding population, but rather just a sign that a small population has survived on Maunakea undetected for decades.
Hart said ‘ua‘u are thought to be genetically distinct island-to-island, or maybe even volcano-to-volcano, as populations on Mauna Loa and Maunakea have not interbred. Therefore, the discovery of a remnant of the formerly abundant Maunakea population was a relief, he said.
“We’ve been looking for them for three and a half years, so I couldn’t believe it,” Hart said. “We really thought the whole population was gone. It was a mixture of elation and relief.”
Hart and other researchers will continue to search for ‘ua‘u and other endangered birds on Maunakea through the end of the year. Meanwhile, the anti-predator measures around the ‘ua‘u burrow will remain for the time being.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.
