The Rat Apocalypse of Lehua


photo by C+H

The Hawaiian island of Lehua will soon be ratless or, if you prefer, without rats. It is not a piper, pied or otherwise, that is leading these rats to their demise. Instead, helicopters are the chosen harbingers of doom. Equipped with bait hoppers full of diphacinone pellets, the whirlybirds of the apocalypse shall descend upon the uninhabited island and discharge their poisonous payload. The Polynesian rats, deemed invasive and destructive, will gorge themselves upon these granules from heaven, and lo! The day of reckoning shall be upon them. Invasive Species on Lehua
Lehua, a Hawaiian state seabird sanctuary, is a 284-acre tuff cone just north of Ni’ihau. The condemned rats are not native to the tiny, crescent-shaped isle. They arrived in the 1930s and have ravenously devoured native plants, luckless eggs, defenseless seeds and hapless birds. Rats weren’t the first invasive pest removed from the island. Feral rabbits, ravagers of the native plant population, were eliminated in 2006 through hunting efforts. Other threats to the island’s native lifeforms include the big-headed ant, barn owls and, ironically enough, Coast Guard helicopters.

How Poisonous is the Poison?
Diphacinone is an anti-coagulant that causes death by internal hemorrhaging in rats. This method of rodent removal has been used before on an islet off the Hawaiian isle of Molokai as well as other places worldwide. According to the US Fish and Wildlife Service, Diphacinone is made out of 99.995% inert grain-based material and will not harm Hawaiian monk seals or sea turtles.

Other safety precautions from the USFWS include:

"The operation will be conducted only during the winter months (December through February) when rat populations and the presence of dependent juvenile rats are lowest and native nontarget migratory species are present in the lowest numbers. In addition, Lehua is rarely used during this time by fisherman, tourists, and opihi pickers.

If the application of rodenticide pellets happens after albatross chicks hatch, then all pellets within 6 feet of each nest will be manually removed so chicks cannot play with or accidentally eat the pellets.

Aerial application is more effective for distributing the pellets over very rough and unsafe terrain, this also results in fewer disturbances to birds and monk seals and is safer on Lehua for all involved, and therefore no bait stations, hand broadcast or burrow baiting will be used."-


Lehua’s Life After Rats
Once the rats are dead, there is hope that the plant and bird populations will heal naturally. There are also plans for a plant restoration project that will help return the island to an approximation of its pre-rat state. The rat apocalypse is scheduled for early January.

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Tags: Animals | Biodiversity | Hawaii