Monitoring Raccoon Rabies in Alabama: The Potential Effects of Habitat and Demographics

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/km2, and lower in the forested habitat at 5 raccoons/ km2. 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). Human-caused 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%).

The Eradication of Bovine Tuberculosis From Infected Wildlife Populations: A New Zealand Scenario

The Animal Health Board (AHB) is the agency responsible for controlling bovine tuberculosis (Tb) in New Zealand. In 2000, the AHB embarked on a strategy designed to reduce the annual period prevalence of Tb infected cattle and farmed deer herds from 1.67% to 0.2% by 2012/13. Under current rules of the Office International des Epizooties (OIE) this would allow New Zealand to claim freedom from Tb. The epidemiology of Tb in New Zealand is largely influenced by wildlife reservoirs of infection and control of Tb vector populations is central to the elimination of Tb from New Zealand’s cattle and deer herds. The AHB has classified New Zealand’s land area into Vector Risk Areas (VRAs) where Tb is established in wildlife (currently 39%) and Vector Free Areas (VFAs) where the disease is not established (61%). Within the VRAs the introduced Australian brushtail possum (Trichosurus vulpecula) is the primary wildlife maintenance host and the main source of infection for domestic cattle and deer herds. Southland is a region of New Zealand with a long history of wildlife associated Tb. Progress in reducing infected herd numbers has been impressive in recent years, primarily due to an intensive possum control program. As a result of this reduction, the focus is now shifting to that of providing increasing levels of confidence that Tb is absent from the remaining susceptible wildlife. High levels of confidence of Tb freedom in wildlife will allow the AHB to reduce the wildlife control programs and ultimately cease control altogether, with minimal risk of Tb reemerging. This paper examines the strategies being utilized to provide that confidence. The types of data, the format in which it is collected and the methods of analysis and review are outlined.

Development of Nicarbazin as a Reproductive Inhibitor for Resident Canada Geese

Expanding populations of resident Canada geese that remain in suburban and urban areas year-round often result in increased conflicts with humans. Non-lethal and humane means are needed for managing the size of Canada goose flocks residing near or on airports, golf courses, industrial parks, government sites, and city parks. A side effect of nicarbazin, a veterinary drug used to control coccidiosis in chickens, is decreased egg production and hatching. Exploiting this side effect, studies of nicarbazin for reducing the hatchability of eggs from Canada geese were conducted. An initial study in Coturnix quail verified reduction in hatchability in a species other than chickens. Because plasma nicarbazin was not routinely measured, a study in chickens was conducted to determine the relationship between plasma and egg nicarbazin. A comparative study in chickens, mallards, and Canada geese showed that nicarbazin absorption was lowest in geese. Studies in both penned and wild Canada geese showed that reduction in hatchability was possible but neither study used bait suitable for general field application. Bait development led to the OvoControl-G® (Innolytics LLC) bait, which resulted in reduction in hatchability of 51% at treated sites compared to control sites in the field. Previous studies showed that nicarbazin is practically non-toxic and is environmentally friendly; timing and management of baiting will minimize non-target hazards. OvoControl-G® 2500 ppm nicarbazin bait is recommended for incorporation into a comprehensive management plan as a reproductive inhibitor for use in controlling resident Canada goose flock sizes.

Effectiveness of Milorganite® as a Repellent to Protect Ornamental and Agronomic Plants From Deer Over-Browsing

When deer populations become locally overabundant, browsing of ornamental and agronomic plants negatively affects plant establishment, survival, and productivity. Milorganite® is a slow-release, organic fertilizer produced from human sewage. We tested Milorganite® as a deer repellent on chrysanthemums (Chrysanthemums morifolium) in an urban/suburban environment, and soybeans (Gycine max) in a rural agriculture environment. Six beds of chrysanthemums at two sites were monitored for 28 to 35 days. Treatment plants received a top dressing of 104 grams of Milorganite® (1120.9 kg/ha). Milorganite® treated plants had more (P < 0.001) terminal buds and achieved greater height (P < 0.002) compared to controls at one site, however damage observed was similar at the second site. In a second experiment, 0.2-ha plots of soybeans (Glycine max) were planted on five rural properties in northeastern Georgia and monitored for ≥ 30 days. Treated areas received 269 kg/ha of Milorganite®. In 4 of 5 sites, Milorganite® delayed browsing on treated plants from 1 week to > 5 weeks post-planting. Duration of the protection appeared to be related to the difference in deer density throughout most of the study areas. Results of this study indicate Milorganite® has potential use as a deer repellent.

Initial Development of a Web-Based Tool to Increase Hunter Harvest of Female Ungulates

Landowners and agencies have expressed difficulty finding hunters willing to harvest the female portion of the ungulate populations, and likewise, hunters have expressed difficulty achieving access to private lands. Since 2003, the Montana “DoeCowHunt” website (www.doecowhunt.montana.edu) has provided an avenue to improve hunter-landowner contact and wild ungulate population management. A product of Montana State University Extension Wildlife Program, this website provides a means for hunters and landowners in Montana to contact each other by listing contact information (email address, physical address, and telephone number) for the purpose of harvesting antlerless ungulates. In the first year over 10,000 users visited the site. Of those who actually registered, 11 were landowners and 1334 were hunters. An evaluation survey resulted in a 40% response rate. The survey indicated the average registered landowner had 20 hunter contacts. Many landowners contacted hunters through use of the website but did not register or list their contact information on the site.

Use of Confined Dogs for Reducing Deer Damage to Apple Orchards

We assessed the efficacy of free-ranging dogs, confined by buried fences and electronic collars, for reducing deer damage to apple trees in three commercial apple orchards in Oswego County, New York State. During 1995 and 1996, we monitored paired dog-protected and control plots in each orchard. Within dog-protected areas, the percentage of damaged buds was lower, and fruit yield was higher in both 1995 and 1996 than for control plots. Gross economic returns were higher from dog-protected than control plots in both 1995 (by 51%) and 1996 (by 184%). After two seasons of growth, trees planted in May 1995 had nearly three times the cross-sectional area, and were 60% taller if they were in dog-protected rather than control plots. Dogs provided increased economic returns for growers at much lower cost than conventional barrier fencing.

Seasonal Carbon Dioxide and Oxygen Concentrations in the Dens of Hibernating Mammals (Sciuridae)

This paper reports seasonal changes in respiratory gases in artificial dens of two species of hibernators indigenous to central and northern Alaska: Citellus parryi ablusus(Osgood) and Marmota broweri Hall and Gilmore (Sciuridae).

A Field-Test of Rhodamine B as a Biomarker in Raccoons

Rhodamine B is a dye that when ingested results in fluorescent bands in growing hair and whiskers of many mammals. Previous research at Wildlife Services’ (WS) National Wildlife Research Center (NWRC) found that rhodamine B is a successful biomarker in raccoon whiskers and that raccoons do not have a taste aversion to the dye when it comprises ≤ 3% of a bait. Our study assessed the ease of bait distribution, whisker collection, and evaluation of the biomarker for potential use in the Oral Rabies Vaccination (ORV) program administered by the WS National Rabies Management Program (NRMP). In collaboration with WS operations personnel from Ohio and Michigan, 750 fishmeal polymer baits each containing 150 mg of rhodamine B were hand distributed at NASA’s Plum Brook Station, Sandusky, Ohio in the summer of 2008. Four weeks after baits were distributed whiskers from 162 raccoons were collected. Wildlife Services biologists and technicians evaluated the whiskers for fluorescence using a handheld UV magnifying lamp. Biologists then sent the whiskers to the NWRC, Ft. Collins, Colorado for confirmation of fluorescence under a UV microscope. Results suggest a high level of agreement between the two methods of evaluation. Surveys completed by biologists confirmed that the ease of use, less invasive sampling techniques and promptness of results obtained through the use of rhodamine B are advantageous to the tetracycline biomarker presently used by the ORV program. All participants recommended further evaluation of rhodamine B for its inclusion in future efforts requiring biomarker evaluation.

The Eleventh Wildlife Damage Management Conference: Table of Contents

Table of Contents

Use of Natural Vegetative Barriers to Limit Expansion of Blacktailed Prairie Dog Towns

Prairie dog (Cynomys ludovicianus) control has historically consisted of lethal methods to maintain, reduce, or eliminate populations in South Dakota and throughout the species range. Non-lethal methods of control are desired to meet changing management objectives for the black-tailed prairie dog. The use of naturally occurring buffer strips as vegetative barriers may be effective in limiting prairie dog town expansion. The objectives of this study were: 1) to evaluate effective width of vegetative barriers in limiting prairie dog towns expansion in western South Dakota; and 2) to document effect native vegetation height on expansion of prairie dog towns in western South Dakota. Five study sites were established in western South Dakota on rangelands containing prairie dog towns of adequate size. Electric fences were constructed for the purpose of excluding cattle and creating buffer strips of native grasses and shrubs. Prairie dogs were poisoned to create a prairie dog free buffer zone adjacent to active prairie dog towns. Grazing was allowed on both sides of the buffer strip. When grazing pressure was not sufficient, mowing was used to simulate grazing. Buffer strips were 100 meters long and 10, 25, and 40 meters in width. A zero meter control was included on all study sites. Quadrats (25) were randomly distributed throughout the buffer strips. Evaluation of study sites included visual obstruction, vegetation cover, vegetation frequency, vegetation height, and vegetation identification. Barrier penetration was evaluated by the presence of new active burrows behind vegetative barriers. Significant relationships were documented for both VOR and vegetation height. No significant difference was found between frequency of breakthroughs and buffer widths.

Assessment of Texas Medical Providers Concerning Rabies Vaccines

Rabies is an important zoonotic disease in Texas and thousands of people each year either request or require rabies prophylaxis because they have ‘high risk’ jobs or are exposed to the disease. After experiencing difficulty in receiving rabies prophylaxis from physicians, we conducted a survey of Texas medical providers to assess their knowledge of rabies vaccine procedures and their experience with rabies vaccines. Most providers in Texas (>95% of 297) rarely saw patients for rabies prophylaxis; therefore, providers have minimal, if any, experience with the procedures of acquiring and administering the vaccine. Providers varied greatly in their responses to our questions of where to acquire the vaccine, how and where to administer the vaccine, and where to acquire information about the vaccine. State and local health departments should target medical clinics and physician associations as outlets to disseminate information regarding rabies, rabies prophylaxis, and treatment.

In-Burrow Application of Rozol to Manage Black-Tailed Prairie Dogs

Our experiment demonstrated that black-tailed prairie dogs (Cynomys ludovicianus) will consume rodenticide underground in their burrows. We demonstrated the efficacy of Rozol Pocket Gopher Bait containing the active ingredient chlorophacione (0.005%) 21 days post treatment for managing black-tailed prairie dogs in their burrows in Kansas. Active prairie dog burrows were reduced 90% when 54 grams of Rozol was placed in the burrow without prebaiting. Results indicate use of this toxicant when placed in the burrow can be an effective means of managing prairie dogs. In-burrow application of rodenticides for black-tailed prairie dog management should markedly reduce exposure of birds to toxic bait.

The Use of Digital Motion-Sensor Cameras to Capture Coyote Presence in Western Georgia

Because of their learned avoidance of humans and the dense cover provided by forested areas, observation of coyote activity is often very limited in the Southeast. In this study we used digital motion-sensor cameras to detect activity among coyote populations in various urban and rural habitats. Camera stations were placed adjacent to regenerating clear cuts, forest trails and roads, agriculture fields, residential areas, and within city parks to determine activity and presence of coyotes in these various areas. Cameras were successful in detecting coyotes in all study sites throughout the year. Coyotes appear to show no avoidance of camera stations. Cameras may be helpful in gathering general biological and activity information on coyote populations in an area.

Modifying Fences to Prevent Ungulate Use of Cropland and High-Value Pastures

Big game can damage crops and compete with livestock for valuable forage. Ranchers have reported their tolerance for big game would increase if the animals could be prevented from using key areas critical for spring livestock use. Likewise, some farmers have high value areas that must be protected. Fences provide the most consistent long term control compared to other deterrent methods, but are costly to erect. Many designs of woven wire and electric fences are currently used. Costs of erecting deer proof fencing could be greatly reduced if an existing fence could be modified instead of being replaced entirely. This study investigates the possibility of modifying existing fences to prohibit deer and elk crossings. Preliminary results indicate effective modifications can be made to existing fences for $1300- $3500 per mile for materials. Traditional complete construction of game fences cost more than $10,000 per mile. These fences may be used in lieu of compensation programs for ranchers. Also, if farmers and ranchers can keep big game out of important foraging areas, their tolerance for these animals on the rest of their property may greatly increase.

Effectiveness of a White-Tailed Deer Exclusion Fence Based on Traction Limitations of the Hoof: The Slippery Fence

We hypothesized that an exclusion fence could be devised to capitalize on traction limitations of the hooves of white-tailed deer (Odocoileus virginianus). Hexagonal plots (9.8 m wide) enclosed by a 2.4 m field fence with two openings (4.9 m) were established. Data were collected daily on consumption of corn provided (2.27 kg) and events recorded by infrared monitors (IR) for treatment and control sites. Five-day treatment periods consisted of test panels (4.9 m x 2.4 m) placed in plot openings at 0°, 5° and 10° slopes, and lubricant applied at the 10° slope. Deer consumed all corn provided at control sites. At the 10° slope, daily corn consumption decreased (1.50 kg ± 0.26, p < .01), and IR events were lower (p < .01) at treatment sites (23.6 ± 3.2) compared to controls (50.3 ± 9.6). With the addition of a lubricant, corn consumption decreased further (p < .001) to 0.17 kg ± 0.03, and IR recorded events were lower (p < .001) at treatment sites (6.58 ± 0.89) compared to controls (44.8 ± 3.1). Results of this study indicate that traction limitation of the hoof can be exploited.