Oregon should revise policy on rodent poisons

By Kim Leval, Debbie Schlenoff and Louise Shimmel
Printed in The Register-Guard
December 27, 2016


We are writing on behalf of the organizations we represent to express concerns about the use of rodenticides such as Rozol to control native species, including boomers, also known as mountain beaver.

In a recent case, opened for public comment, Rozol was proposed for use to kill native boomers on 183.6 acres of private timberland near Florence, in the Siltcoos Lake drainage. Public and industrial use of anticoagulant poisons such as Rozol not only kill the targeted animals, but also nontargeted species.

There are better ways to manage wildlife that create problems, whether in forestry or in urban chicken keeping. We need to revise policies in Oregon that allow the use of these poisons because of the risks they pose to nontargeted animal species.

Animals sickened by anticoagulants become dehydrated from bleeding internally and seek out water. Rozol pellets may continue to be eaten for several days, with the poison accumulating at levels several times the lethal dose. The label clearly states that Rozol is “extremely toxic to birds and mammals.”

Specific examples of anticoagulant-poisoned raptors that the Cascades Raptor Center has seen recently include an entire screech owl nest poisoned inadvertently in the River Road area, a barred owl from a gated community in Florence, and poisoned barn owls from Pleasant Hill and west Eugene. All were killed by indiscriminant use of these poisons.

Our concerns include:

1) Effects on predators and scavengers: Rozol is a slow-acting poison, meaning that poisoned animals will be mobile and easy prey for several days. Even when the pellets are placed in dens, poisoned animals will roam because of the weakness and dehydration caused by the anti­coagulant.

Subsequently, the sickened (or dead) animals are then exposed to predators or scavengers in the area who, in turn, are poisoned. It is almost impossible to effectively find and remove poisoned carcasses before predators or scavengers obtain them.

2) Effects on other animals that ingest the pellets: Pet dogs, other domestic animals and other nontargeted animals that enter burrows may be exposed to poisons, further perpetuating the potential for poisoning of nontargeted species.

3) Effects on waterways and aquatic animals: According to the label, the rodenticide Rozol should not be used near water, when rain is forecast or where runoff might occur. It is poisonous to fish, amphibians and aquatic invertebrates. When the application site contains waterways, they may become contaminated by poisoned and dead animals.

4) Ecosystem-wide effects: Native predators are critical for healthy functioning ecosystems. Ironically, as the predators and scavengers in the area succumb to the poison, the natural control on all rodent pest species becomes less effective, possibly resulting in the use of more poisons.

Boomers mainly eat ferns, salal, nettles, fireweed, brambles and, only occasionally, very young trees. Boomers are unique to our area and provide burrows for other animals, including their natural predators. Boomers are not a social species, and their home ranges can be up to two acres, which makes it unlikely that the number of boomers in the area where Rozol use is prescribed warrants a wholesale poisoning campaign.

There are better ways to manage rodents, whether at your own home in forestry or in your urban backyard chicken coop. Look for healthier options. Both Ore­gon and Washington have suggestions for nonpesticide boomer control. These include fencing of vulnerable plants, repellants, and harassment at the burrows.

Using rodenticides for home, farm, chicken coop or forest management does not justify the danger to our pets, the harm done to our native fish and wildlife, or the long-term risk to our valued waterways and ecosystems.

We need stronger safety measures in Oregon that include restricted use of rodenticides and better education about alternative management practices that are healthier for people, fish and wildlife, and our waterways.

Please call your legislators and ask them to take action on this issue. If you have a rodent problem, ask your pest managers for alternatives to rodenticides, such as Integrated Pest Management.

Call the Northwest Center for Alternatives to Pesticides (541-344-5044) for help and referrals, or go to its website at www.pesticide.org and look under the resources tab.

Kim Leval is executive director of the Northwest Center for Alternatives to Pesticides. Debbie Schlenoff is conservation chair and board member of the Lane County Audubon Society. Louise Shimmel is founder and executive director of the Cascades Raptor Center.

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