The Role of Toxicants in Forest Management

Although the emphasis of the Olympia Field Station is on the development of non-lethal methods to control pest species, sometimes lethal methods are necessary. Toxicants can be an effective means of quickly reducing high populations of some problem animals or maintaining acceptable population densities. Depending on their mode of action, toxicants are classified into three categories: fumigants, acute toxicants and chronic toxicants

Is it a Pocket Gopher or Mole?

Depending on where you are, the term “gopher” is applied to a variety of mammal species including ground squirrels, prairie dogs and moles. The true pocket gopher is actually very distinguishable once you recognize their appearance and sign, or indicators of the animal. Pocket gophers are burrowing rodents named for their external fur-lined cheek pouches. Unlike mole mounds, which have been characterized as miniature volcanoes, gopher mounds are fan-shaped in appearance. Pocket gophers are distributed throughout the Pacific Northwest, but occur more frequently in the drier climates of eastern Washington and Oregon

The Role of Toxicants in Forest Management

Although the emphasis of the Olympia Field Station is on the development of non-lethal methods to control pest species, sometimes lethal methods are necessary. Toxicants can be an effective means of quickly reducing high populations of some problem animals or maintaining acceptable population densities. Depending on their mode of action, toxicants are classified into three categories: fumigants, acute toxicants and chronic toxicants

Assessing the efficacy of registered underground baiting products for mountain beaver (Aplodontia rufa) control

The mountain beaver (Aplodontia rufa) is a fossorialrodent species endemic to the Pacific Northwest and portions of California. This herbivore inflicts millions of dollars of damage annually to forest seedling plantations. Currently, extensive trapping prior to planting is the most reliable method for reducing damage. With increasing restrictions placed on trapping, forest resource managers need alternative tools to minimize forest damage. This study assessed the potential of four toxicants registered for underground use to controlmountain beaver; zinc phosphide, diphacinone, chlorophacinone, and strychnine. Zinc phosphide and strychnine are acute toxicants, whereas diphacinone and chlorophacinone are anticoagulants. Anticoagulants prevent the recycling of vitamin K in the body, which inhibits the production of clotting factors. Efficacy varied among treatments. Zinc phosphide and strychnine were avoided by mountain beaver. Pre-baiting marginally increased acceptance of strychnine, but did not alter mountain beaver acceptance of zinc phosphide. Diphacinone and chlorophacinone were both readily consumed, but only chlorophacinone was 100% effective after a 14-day baiting regime. Subsequently, we tested the effects of diet on the efficacy of diphacinone by varying the availability of food containing vitamin K, the anticoagulant antidote. Restricting access to potential sources of vitamin K appeared to increase efficacy. We conclude that anticoagulants hold some promise as additional tools for managers to reduce mountain beaver populations with chlorophacinone showing the most promise. However, limitations to anticoagulant baits include the necessity of long-term baiting (greater than 10 days), a possible decrease in toxicity if baits contact moisture, and potential primary hazards

Assessing the efficacy of registered underground baiting products for mountain beaver (Aplodontia rufa) control

The mountain beaver (Aplodontia rufa) is a fossorialrodent species endemic to the Pacific Northwest and portions of California. This herbivore inflicts millions of dollars of damage annually to forest seedling plantations. Currently, extensive trapping prior to planting is the most reliable method for reducing damage. With increasing restrictions placed on trapping, forest resource managers need alternative tools to minimize forest damage. This study assessed the potential of four toxicants registered for underground use to controlmountain beaver; zinc phosphide, diphacinone, chlorophacinone, and strychnine. Zinc phosphide and strychnine are acute toxicants, whereas diphacinone and chlorophacinone are anticoagulants. Anticoagulants prevent the recycling of vitamin K in the body, which inhibits the production of clotting factors. Efficacy varied among treatments. Zinc phosphide and strychnine were avoided by mountain beaver. Pre-baiting marginally increased acceptance of strychnine, but did not alter mountain beaver acceptance of zinc phosphide. Diphacinone and chlorophacinone were both readily consumed, but only chlorophacinone was 100% effective after a 14-day baiting regime. Subsequently, we tested the effects of diet on the efficacy of diphacinone by varying the availability of food containing vitamin K, the anticoagulant antidote. Restricting access to potential sources of vitamin K appeared to increase efficacy. We conclude that anticoagulants hold some promise as additional tools for managers to reduce mountain beaver populations with chlorophacinone showing the most promise. However, limitations to anticoagulant baits include the necessity of long-term baiting (greater than 10 days), a possible decrease in toxicity if baits contact moisture, and potential primary hazards

Coyote and Wolf Habitat Use in Northwestern Montana

Being a habitat generalist is an adaptation suategy that has allowed the coyote to expand its range. As wolves reestablish, or are reintroduced, resident populations of coyotes may change habitat use. We compared habitat use between coyotes and wolves in Glacier National Park after successful recolonization by wolves. Two wolf oacks and nine coyotes were monitored from June 1994 throueh June 1997 to determine habitat use in northwestern Montana. Wolves used habitat types within their home ranges in proportion to availability during the winter, but not the summer when more open areas and burned forests were used. Most coyotes used habitat types within their home ranges in proportion to availability in summer and winter. Coyotes may use open habitats to avoid encounters with predators other than wolves (i.e., cougars), and for access to small mammals during the summer. In addition, coyotes used areas closer to roads than wolves, and used NE-NW aspects more frequently while wolves occupied SE-SW and SW-NW aspects. Although habitat use was similar between canids, coexistence of coyotes and wolves in the Glacier National Park area may be facilitated through differential use of topographic charactenstics (i.e., slope, aspect, and areas near roads)

MONITORING RACCOON RABIES IN ALABAMA: THE POTENTIAL EFFECTS OF HABITAT AND DEMOGRAPHICS

Abstract: Density, morphometrics, and disease prevalence of raccoon populations were determined in 4 habitats (agriculture, riverine, managed, and forested) in central Alabama. In addition we monitored 71 collared raccoons to determine survival. Density estimates were similar in the agriculture (ag) and riverine habitats in central Alabama with 8 raccoons/km 2 , and lower in the forested habitat at 5 raccoons/ km 2 . Retention of juveniles did not appear to contribute to observed higher populations in the riverine and ag habitat. Although the riverine and ag, possibly due to supplemental resources, likely provide better habitat for raccoons, we found only body size in female raccoons to be different across habitats (P = 0.001). Humancaused mortality (either hunting or missing and presumed killed) was the main cause of mortality in several raccoon populations during fall; however, fall survival did not differ between the habitats (χ = 1.47, d.f. = 3, P = 0.69). Although rabies and distemper virus were prevalent in all habitats, they did not appear to contribute to mortality even with a high proportion of the population exhibiting positive CDV titers (ag -44%, managed-50%) and rabies titers (managed-57% and riverine habitat-60%)

Assessing the Efficacy of Chlorophacinone for Mountain Beaver (\u3ci\u3eAplodontia rufa\u3c/i\u3e) Control

The mountain beaver is a fossorial rodent species endemic to the Pacific Northwest and portions of California. This herbivore is managed as a pest species because of the impact it has on newly planted Douglas-fir seedlings. Currently, managers are limited to trapping for population control; however, in Washington trapping has been further curtailed by anti-trapping legislation. Presently there are no registered underground toxicants for mountain beaver control. We have documented the efficacy of chlorophacinone, presented in daily doses, as a possible alternative for mountain beaver control. Daily baiting would be unreasonable and costly alternative for timber managers, so we conducted a series of tests to determine if a single or double baiting was efficacious. In addition, we tested the caching behavior of the mountain beaver when offered bags of oats. This behavior may help reduce impacts to non-target species as well reduce environmental exposure and degradation. Mountain beaver readily cached bags of chlorophacinone within their artificial burrows, and efficacy of a one-lime and two-time dose was 100%. We determined that even with the highest chlorophacinone residuals (0.354 ppm) that the risk quotient for mink and red-tailed hawk was exactly at the level of concern that EPA recognizes for endangered and threatened species

Assessing the Efficacy of Chlorophacinone for Mountain Beaver (\u3ci\u3eAplodontia rufa\u3c/i\u3e) Control

The mountain beaver is a fossorial rodent species endemic to the Pacific Northwest and portions of California. This herbivore is managed as a pest species because of the impact it has on newly planted Douglas-fir seedlings. Currently, managers are limited to trapping for population control; however, in Washington trapping has been further curtailed by anti-trapping legislation. Presently there are no registered underground toxicants for mountain beaver control. We have documented the efficacy of chlorophacinone, presented in daily doses, as a possible alternative for mountain beaver control. Daily baiting would be unreasonable and costly alternative for timber managers, so we conducted a series of tests to determine if a single or double baiting was efficacious. In addition, we tested the caching behavior of the mountain beaver when offered bags of oats. This behavior may help reduce impacts to non-target species as well reduce environmental exposure and degradation. Mountain beaver readily cached bags of chlorophacinone within their artificial burrows, and efficacy of a one-lime and two-time dose was 100%. We determined that even with the highest chlorophacinone residuals (0.354 ppm) that the risk quotient for mink and red-tailed hawk was exactly at the level of concern that EPA recognizes for endangered and threatened species

Assessing the Efficacy of Chlorophacinone for Mountain Beaver (\u3ci\u3eAplodontia rufa\u3c/i\u3e) Control

The mountain beaver is a fossorial rodent species endemic to the Pacific Northwest and portions of California. This herbivore is managed as a pest species because of the impact it has on newly planted Douglas-fir seedlings. Currently, managers are limited to trapping for population control; however, in Washington trapping has been further curtailed by anti-trapping legislation. Presently there are no registered underground toxicants for mountain beaver control. We have documented the efficacy of chlorophacinone, presented in daily doses, as a possible alternative for mountain beaver control. Daily baiting would be unreasonable and costly alternative for timber managers, so we conducted a series of tests to determine if a single or double baiting was efficacious. In addition, we tested the caching behavior of the mountain beaver when offered bags of oats. This behavior may help reduce impacts to non-target species as well reduce environmental exposure and degradation. Mountain beaver readily cached bags of chlorophacinone within their artificial burrows, and efficacy of a one-lime and two-time dose was 100%. We determined that even with the highest chlorophacinone residuals (0.354 ppm) that the risk quotient for mink and red-tailed hawk was exactly at the level of concern that EPA recognizes for endangered and threatened species