AR-News: (US) HI: Unexpected feral pig deaths halt rat poisoning

[cathy goeggel]

http://the.honoluluadvertiser.com/article/2004/May/03/ln/ln10a.html
Posted on: Monday, May 3, 2004
Ka'u rat-control program halted after deaths of feral pigs

By Jan TenBruggencate
Advertiser Environment Writer

Kamehameha Schools has halted its rat-control program in the forests of Ka'u
on the Big Island after a dozen pigs died last year from eating poisoned
bait.

Officials said it was the first known case of feral pigs going after rat
bait, and the first known Hawai'i feral pig fatalities from the chemical
diphacinone.

Rats are considered one of the primary threats to native birds and plants in
the Hawaiian forest because they eat eggs, chicks, seeds and seedlings.

Hundreds of rats and mice were killed in the same period as the pig deaths,
according to landowner Kamehameha Schools.

Diphacinone is a blood-thinning, or anti-coagulant, compound sometimes used
in human medicine. It acts much like the more familiar rat bait warfarin.

"Kamehameha Schools regrets the inadvertent loss of the pigs in this
situation. While we do work with the local hunting community to control wild
pig populations on our land, our target in this case was the rat," said
schools Hawai'i Island region manager Robert Lindsey.

Studies with domestic pigs had suggested the animals were tolerant to the
chemical and not at risk, the schools said in a press release.

The landowner said it had been controlling rats in the area with bait traps
for about 10 years without any pigs breaking open the sturdy plastic traps
anchored by fence posts and 2-foot-long ground spikes.

In a test in August, the schools distributed fish-flavored diphacinone bait
aerially on about 750 acres of forest in addition to bait traps. The U.S.
Environmental Protection Agency approved the test.

"We think the pigs got a taste for the aerial bait, and then went after the
bait traps," said wildlife biologist Tonnie Casey.

Reach Jan Tenbruggencate at (808) 245-3074 or at
jant at honoluluadvertiser.com.