HAWAI'I'S ENVIRONMENT
Rat poison creates problems
By Jan TenBruggencate
Advertiser Columnist
Q. Rats breeding in a canal near our home on Kane'ohe Bay Drive have been coming into our yard. We've been using rat poison, placed on a two-by-four, but birds and other animals have been eating it. Is there a safer way to control rats?
— B.C., Kane'ohe
A. A survey of resources on rat control and a discussion with University of Hawai'i rat expert Barry Brennan, pesticide coordinator with the Cooperative Extension Service, yielded some tips.
First, find the reason rats are entering your property. Remove food sources near the home, such as pet food, bird seed, and fruit that may have fallen to the ground. Clean up hiding places such as stacked lumber or gardening supplies next to the foundation. Repair any leaking outdoor plumbing; Norway rats, particularly, require a lot of water.
If they're entering your home, find out how, and seal holes with concrete, lumber or heavy-gauge wire mesh.
Consider all other options before poisons, which can hurt other wildlife and children, can cause suffering to the rats, and can result in rats dying and decomposing in inaccessible places around or under your home.
Snap traps and cage traps can be effective. Good baits include dried fruit, peanut butter, cheese and anything the rats have been feeding on around your home. Let them feed from an unset trap for a few nights before setting it.
"They tend to be very smart," Brennan said.
If you must use poisons, make them tamper proof. One technique is to put the poison bait inside a piece of 3- or 4-inch pipe a couple of feet long, where birds can't see it and where cats, dogs and children can't get at it.
Hawai'i has four rodents of note. The biggest is the Norway rat (Rattus norvegicus), which can weigh a pound and can be brown, gray or black in color. It has small ears, a blunt nose and a stout tail shorter than the 10-inch length of its head and body combined. It tends to live in moist areas.
The black rat (Rattus rattus), also known as the ship rat or roof rat, grows to half a pound, is gray or black in color with a tail longer than its 6-inch head and body. It readily climbs trees or wires, and likes ceilings and attics.
The 3-ounce Polynesian rat (Rattus exulans), which can be brown on top and tan or gray below, tends to be a field animal and isn't normally found around homes.
The house mouse or field mouse (Mus musculus) is light brown to light gray and weighs just half an ounce.
If you have an issue, question or concern about the Hawaiian environment, drop a note to Jan TenBruggencate, The Advertiser's Kaua'i Bureau chief and its science and environment writer. Reach him via e-mail at jant@honoluluadvertiser.com, by telephone at (808) 245-3074, or by mail at P.O. Box 524, Lihu'e, HI 96766.
