AR-News: (US) HI: Keahou Ranch to continue rat poisonings

[cathy goeggel]

Posted on: Monday, May 10, 2004

HAWAI'I'S ENVIRONMENT
Rat control meant to help birds

By Jan TenBruggencate
Advertiser Columnist

Some wildlife officials are hoping that controlling rats, which compete with
Hawaiian forest birds for food, will prompt some of the birds to begin
nesting year-round, or over a longer season, instead of just in winter.

Kamehameha Schools wildlife biologist Tonnie Casey said rats may compete for
food so effectively most of the year that the birds lack energy to
reproduce.

"If we get rats down to really low numbers, we may get nesting year-round,"
she said.

U.S. Fish and Wildlife Service biologist Eric VanderWerf is not so hopeful.

"Nesting is a big cost to the parents. It's a common pattern that birds time
their reproduction to coincide with peaks in food availability. I kind of
doubt that they would begin nesting at other times," he said.

However, controlling a major food competitor could make things easier. "It's
possible they will increase the length of the nesting season, and we may see
more nesting success," VanderWerf said.

Scientists will test the rat-control theory on a large chunk of koa
forestation land owned by Kamehameha Schools. The 3,000-acre fenced section
of Keauhou Ranch is between the 5,500- and 6,200- foot elevation on the
slopes of Mauna Loa.

Rat control was temporarily stopped there recently after feral pigs began
eating the rat bait and died. The pigs previously ignored the enclosed bait
stations, but after they got a taste for the fish-flavored bait during air
drops of unshielded bait pellets last summer, they began breaking into the
sturdy bait containers.

"Pigs had been left in the area to see what would happen. We've learned now
that we have to take the pigs out of an area if we want to use aerial bait
distributions," Casey said.

Pigs are now being eradicated within the fenced area, and bait placement
will resume in November.

"We will start rat control for the December bird nesting season," Casey
said. "We'll keep it up until the young birds fledge" and are able to fly
away and protect themselves from rats, who have been known to prey directly
on eggs and young birds as well as compete for food.

Casey said the Keauhou Ranch acreage has a good collection of endangered and
other native birds, including 'akiapola'au, Hawai'i creeper, Hawai'i 'akepa,
'elepaio, 'apapane, 'i'iwi, Hawaiian thrush or 'oma'o, Hawaiian hawk or 'io
and Hawaiian goose or nene.

If you have a question or concern about Hawai'i's environment, contact Jan
TenBruggencate at jant at honoluluadvertiser.com, (808) 245-3074, or P.O. Box
524, Lihu'e, HI 96766.