Black Bear Use of Forest Roads in Western Washington

Radiolocations (108) of 20 black bears were used to assess use or avoidance of 3 forest road types in western Washington. Distances of bears to each type of road were compared to distances of 108 random points using t-tests. Females and males avoided 2-lane roads, while only males avoided 1-lane roads, the most common road type in the area. Females, but not males, were located closer to overgrown, spur roads than expected. This road type has substantial cover of grasses, forbs, and berry-producing shrubs along with protective tree cover. This situation may provide easy travel for females along with security cover and a relatively abundant source of high-energy foods that could favor high reproductive success. It also suggests that 1-lane roads and overgrown roads are the best places to locate supplemental feeding stations aimed at providing nutrition to female bears in the spring

Reducing Prairie Dog Populations and Damage by Castration of Dominant Males

Black-tailed prairie dogs (Cynomys ludovicianus) occur widely across the prairie states of North America. They compete with livestock for forage, transmit plague, and damage lawns, landscaping, and property. Interest in non-lethal methods, such as immunocontraception, is growing; however, reductions in the population due to contraception may be offset by increases in survival because adults and yearlings are not subject to the energetic demands of reproduction, and lower densities may increase the amount of resources available to growing offspring. Surgical sterilization provides a means for modeling these effects. Thus, we castrated males prior to the 1998 breeding season to simulate the potential effects of some contraceptives on body mass and survival. During the summer following treatment, the proportion of male and female adults/yearlings and juveniles captured did not differ between treatment and control coteries; however, the proportion of adults and yearlings captured decreased with later trapping periods. Hence we cannot recommend castration of dominant males to reduce colony expansion and damage by prairie dogs. Other methods of fertility control (GonaCon and diazacon) have shown more promise in prairie dogs

Perspectives on Existing and Potential New Alternatives to Anticoagulant Rodenticides and the Implications for Integrated Pest Management

Comprising over 1400 species worldwide, rodents are the largest taxonomic group of mammals (Nowak 1999). Rodent use of habitats is extensive and varied. Most rodent species are relatively small, secretive, prolific, adaptable, and have continuously growing incisors which require constant eroding by gnawing. Rodents are known for their high reproductive potential; however, there is much variability between species as to the age at first reproduction, size of litters, and the number of litters per year. All rodent species have ecological, scientific, social, and/or economic values. They recycle nutrients, aerate soils, distribute seeds and spores, and affect plant succession. Some provide meat and furs for people. Several species are used in large numbers in medical research. Additionally, they provide an important prey base for many species of predatory animals

Rodent outbreaks in North America

Fluctuations in rodent population densities in North America are a reality. Our understanding of the factors causing such fluctuations is incomplete; therefore, it is important to monitor populations to increase our understanding of natural wildlife communities so as to avoid substantial damage to agriculture, forestry, and urban infrastructures, and to prevent rodent-borne disease transmission to humans. There is a need to establish integrated pest management programs in which monitoring, preventive cultural practices, and various control methods (mechanical, physical, biological, and chemical) are strategically coordinated to maintain rodent population densities at acceptable pest levels

STATUS OF COYOTES AND COYOTE DEPREDATIONS IN PENNSYLVANIA

The coyote (Canis latrans) population in Pennsylvania has grown in the last several decades to about4,000. It continues to grow, despite a known annual harvest of more than 850 animals. There is a growing concern about the effects of coyotes on game and livestock populations. We discuss known and potential coyote-human conflicts in Pennsylvania and propose a program of depredation prevention and control. To be successful, the program requires cooperation, funding, research, educational materials, and training workshops

Rodent outbreaks in North America

Fluctuations in rodent population densities in North America are a reality. Our understanding of the factors causing such fluctuations is incomplete; therefore, it is important to monitor populations to increase our understanding of natural wildlife communities so as to avoid substantial damage to agriculture, forestry, and urban infrastructures, and to prevent rodent-borne disease transmission to humans. There is a need to establish integrated pest management programs in which monitoring, preventive cultural practices, and various control methods (mechanical, physical, biological, and chemical) are strategically coordinated to maintain rodent population densities at acceptable pest levels

A field evaluation of a trap for invasive American bullfrogs

Native to the eastern United States, American bullfrogs (Rana catesbeiana [Lithobates catesbeianus]) have been introduced in many countries throughout the world. There have been relatively few effective and efficient control methods developed to manage bullfrogs. Particularly in the Hawaiian Islands, Pacific coast of North America, and Japan, finding effective methods for controlling invasive bullfrogs is needed with special emphasis on low impacts for sensitive native species. We conducted a field study to examine the efficacy of a newly designed live trap for capturing invasive bullfrogs. We found that our trap was successful at capturing bullfrogs because we captured up to seven in a single trap overnight. Fishing lures, live crickets, and lights were used as attractants and all capture bullfrogs, however more research is needed for finding effective attractants. We captured one known non-target frog that was released. Our findings suggest that the multiple capture traps could effectively be used as part of an integrated pest management strategy for controlling invasive bullfrog populations

Introduced Wildlife of Oregon and Washington

Each species of wildlife occurs as part of an ecosystem, interacting in many ways with other plant and animal species in that system as well as with the abiotic components such as soil, air, water, and other substrates. The array of wildlife species around the globe has been shaped by geological and climatological events as well as by eons of evolution and natural selection. Species have come and gone and those remaining have, in most cases, co-evolved or co-adapted with many other species so that relatively stable, and often complex, relationships exist. Usually, a great many niches have been carved out and occupied, creating a distinct flora and fauna in each region of the globe that is maintained under conditions of relative stability over time. Natural disturbances (wind, fire) and large-scale events (volcanic eruptions, drought) may occasionally alter that stability and the relationships between species, but an overall homeostatis a return to the climatic community steady state usually prevails. These and other concepts of biogeography have been discussed in detail

Understanding Vole Problems in Direct Seeding — Strategies for Management

Crop fields can provide habitat to a variety of wildlife and crop damage can result (Wywialowski 1996, 1998; Conover 1998). Among the vertebrates, damage can occur from numerous species of birds and mammals. Worldwide concern, however, has focused on rodents and a large number of species cause substantial agricultural losses each year (Witmer et al. 1995). After the advent of effective herbicides and clean farming practices in North America, however, many rodent problems became insignificant (Hines and Hygnstrom 2000). This is, in large part, because the fields were plowed each year, disrupting burrows and removing ground cover. The fields often lay bare a lengthy part of the year. The use of herbicides, plowing, and burning prevented the fields from developing the vegetative cover that wildlife needed for year-round food and shelter. This situation has been changing in recent years. The use of conservation tillage or no-till agriculture is increasing across much of North America, in part because these methods conserve soil and water resources. Many problems can arise, however, and an integrated pest management strategy is needed to deal with weed, insect, and vertebrate pests that can proliferate and cause substantial damage in the no-till agriculture setting (Holtzer et al. 1996). When the ground is not plowed each year, crop residues are maintained, and surrounding areas provide good harborage for rodents, the potential exists for substantial increases in rodent populations and subsequent crop damage. The microtine species group (Subfamily Microtinae, Nowak 1991) contains many species that are serious pests throughout the northern hemisphere. In North America, many of the pest species belong to the genus Microtus, commonly called voles or meadow mice. In this paper, we review the literature and provide background information on voles and the damage they cause. We also discuss management strategies that can help reduce agricultural damage by voles

Design of a Self-Resetting, Low-Maintenance, Long-Term Bait Station for Rodent Control

A low-maintenance, long-term bait station that resets itself after being triggered would be a very useful tool for controlling Richardson’s ground squirrels, or other problem rodent species, in remote locations. With collaborators, we developed and tested two such devices using lab rats in pen settings. The devices can be left in-situ for long periods of time without servicing, and requires only occasional bait and/or battery replacement. Squirrels would be unable to cache bait due to the integrated time-out mechanism. The devices use capacitive sensor or strain gauge systems for animal identification, making it very unlikely that smaller non-target species would be able to trigger the systems while the design precludes entry by larger non-target species. Further refinement and testing will be needed before a viable, commercial product can go into production. These refinements include increasing reliability, reducing power requirements, design features and triggering mechanisms tightly linked to the attributes of the targeted pest species, and reduction of production costs. The devices will also need to be tested in field settings for extended periods of time