ARTICLES ON HAWAIIAN BIRDS AND BIRDWATCHING AND OTHER PACIFIC WILDLIFE

CATS KILL INDIGENOUS BIRDS by Maui News, August 2002.
http://www.maui.net/~mauinews/lnews4a.htm


HOOKIPA - A feral cat or cats are likely responsible for killing nearly the entire Hookipa colony of wedge-tailed shearwaters, a total of 93 indigenous Hawaiian seabirds, over the past two weeks. "I just get so sick of doing this," said state wildlife biologist Fern Duvall as he trudged up and down the slope filling plastic trash bags with carcasses. He said the colony gets hit "all the time." Bite marks on the birds' chests and heads were typical of cat kills. The fact that the carcasses were left intact indicate the guilty feline was hunting out of instinct, not for food. Duvall said a single cat could have caused all the damage. "An animal probably found the colony and it's just coming back repeatedly," he said.

Wedge-tailed shearwaters, or 'ua'u kani, are about 17 inches long, with sooty-brown feathers and a slender, hooked bill. There are 73 known shearwater burrows on the windswept slope near Hookipa Beach Park, each home to a nesting pair. Only one hole appeared to still be occupied when Duvall inspected the site on Wednesday afternoon. He called the deaths "a major hit" to the colony, adding that he hoped the birds that are still out at sea leave the area when they see their nests are abandoned and their eggs are cold.

For two years state officials have been banding shearwaters at the site, which is one of eight monitored colonies on Maui. None of the banded birds were among the dead, allowing Duvall to hope that some of them will return to nest in the future, re-establishing the colony after the cat problem has been addressed. Duvall said that the only way to protect the birds, which are awkward on land and not accustomed to dealing with predators, is to control the nearby cat population. "We've just got to start getting more aggressive about it," he said.

Animal Control Supervisor Aimee Anderson with the Maui Humane Society said no caretaker has registered a cat colony in the Hookipa area. She said the Humane Society could work with the state to trap any wild cats that have been killing birds there. "We don't want to see natural bird populations decimated," she said. Duvall said the kill's timing is somewhat unusual. Cats usually are attracted to shearwater sites before eggs are laid in early June, when the birds are at the peak of calling to each other, or right after the eggs hatch, when hungry chicks call to parents returning from sea.

Wedge-tailed shearwaters are a relatively common ocean bird around the Pacific and Indian oceans, and are not considered threatened or endangered. The majority of the birds live on offshore islands where they are not threatened by cats and other predators. The population nesting at the Hookipa slope likely selects the site because it faces into a strong breeze; they like to be able to take off into the wind right from the mouths of their deep burrows. The colony, which is located on an old dump site, also offers many natural holes and loose dirt that is good for digging with beaks and claws.

Maui News, August 2002.

CATS SUSPECTED IN SEA-BIRD KILL ON MAUI By Timothy Hurley, Honolulu Advertiser, August 2002.
http://the.honoluluadvertiser.com/article/2002/Aug/09/ln/ln23a.html

HO'OKIPA, Maui - A rare colony of wedge-tailed shearwaters, a native Hawaiian sea bird, was nearly wiped out by one or more feral cats in attacks over the last two weeks, a state wildlife official said yesterday. "This is a terrible biological loss,'' said state wildlife biologist Fern Duvall. In all 96 adult birds were killed and 22 eggs destroyed. The bite marks on the breasts and heads of the dead birds match the bite of a cat. The carcasses were left intact, indicating that the kills were not for food.

During an inspection of the site near Ho'okipa Beach Park yesterday, Duvall found only 15 of the colony's 73 burrows still
active. But the number of deaths likely will rise, he said, because two shearwater parents are required to raise a chick. While the wedge-tailed shearwater, or 'ua'u kani, is abundant in the Northwestern Hawaiian Islands, most of the birds around the main islands inhabit offshore islets where they are not threatened by cats and other predators. The Ho'okipa colony is one of eight Maui communities of the brown-and-gray sea bird that is about the size of a pigeon. Scientists have been banding younger shearwaters at the former dump site near Ho'okipa Beach Park for three years.

Judging from the decomposed condition of the bird carcasses, Duval said that the carnage apparently began two weeks ago,
with most of the kills occurring in the last five days. Duvall said the Ho'okipa colony has been hit by cat kills before and he suspects that one or more animals from a cat colony maintained at or near the beach park is responsible for the damage.
But Aimee Anderson, animal control supervisor with the Maui Humane Society, said there is no record of a cat colony in the
Ho'okipa area. While that doesn't rule out the possibility that someone is feeding cats in the area, animal control officers who
patrol the park twice a week for leash-law violations haven't seen any cats, she said. Anderson said the Maui Humane Society would be willing to help the state trap any cats that have been killing birds there. "We're not going to put cats above the native species,'' she said.

While the Ho'okipa colony is virtually decimated for now, there is hope that it will recover in the years to come. Duvall said
fledglings leave the nest for four years and don't come back until they are sexually mature. None of the banded birds were
killed in the attacks, he said. The threat of attack from wild cats is a constant one for sea birds in the main Hawaiian islands and especially for the wedge-tailed shearwater, which is awkward on the ground and unaccustomed to dealing with predators.
A study of Maui wedge-tailed shearwaters in 1999 and 2000 found that 65 percent of nested burrows failed to yield new
birds, largely because of feline predation, Duvall said. By comparison, only 17 percent of the burrows at Molokini islet, which
is free of cats, failed, and that was because of predation by native frigate birds.

Hawai'i's wedge-tailed shearwaters arrive on land in March. The pairs dig a burrow, and the female lays a single egg in June.
Usually arriving at the nest at dusk and leaving again at dawn, the parents take turns feeding the burrowed chick.

Timothy Hurley, Honolulu Advertiser, August 2002.

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