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Declining Mortality In American Crow (Corvus Brachyrhynchos) Following Natural West Nile Virus Infection, Lisa M. Reed, Michael A. Johansson, Nicholas Panella, Robert Mclean, Terry Creekmore, Rose Puelle, Nicholas Komar

United States Department of Agriculture Wildlife Services: Staff Publications

The American crow (Corvus brachyrhynchos) is known to suffer 100% mortality from infection with the New York 1999 strain of West Nile virus (WNV). Following the initial detection of WNV in North America in 1999, we measured prevalence of WNV-reactive antibodies (‘‘seroprevalence”) in free-ranging American and fish crows (Corvus ossifragus) of central New Jersey after each transmission season through 2005. In 2002, seroprevalence in American crow juveniles increased to 14% from the 5% of the previous year, potentially indicating increased survival in this species. Using the annual seroprevalence measurements and the number of human West Nile …

Invasive Litter, Not An Invasive Insectivore, Determines Invertebrate Communities In Hawaiian Forests, Nathania C. Tuttle, Karen H. Beard, William C. Pitt

United States Department of Agriculture Wildlife Services: Staff Publications

In Hawaii, invasive plants have the ability to alter litter-based food chains because they often have litter traits that differ from native species. Additionally, abundant invasive predators, especially those representing new trophic levels, can reduce prey. The relative importance of these two processes on the litter invertebrate community in Hawaii is important, because they could affect the large number of endemic and endangered invertebrates. We determined the relative importance of litter resources, represented by leaf litter of two trees, an invasive nitrogen-fixer, Falcataria moluccana, and a native tree, Metrosideros polymorpha, and predation of an invasive terrestrial frog, Eleutherodactylus …

Feasibility Of Infectious Prion Digestion Using Mild Conditions And Commercial Subtilisin, John L. Pilona, Paul B. Nash, Terry Arver, Don Hoglund, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Two serine protease enzymes, subtilisin 309 and subtilisin 309-v,were used to digest brain homogenates containing high levels of prion infectivity using mildly alkaline conditions to investigate prion decontamination methods. To establish that PrP^res infectivity was eliminated, we utilized the Rocky Mountain Laboratory (RML) mouse-adapted scrapie model system for bioassay. Only one digestion condition (subtilisin 309 at 138mAU/ml, 55 ◦C and 14 h digestion time pH 7.9) was considered to be highly relevant statistically (P < 0.001) compared to control, with 52% of challenged mice surviving until the end of the study period. In contrast, treatment of PrP^res by autoclaving at 134 ◦C or treatment with hypochlorite at a concentration of 20,000ppm completely protected mice from prionosis. Further, in vitro assays suggest …

Eight Polymorphic Microsatellite Loci Developed And Characterized From Townsend’S Big-Eared Bat, Corynorhinus Townsendii, Antoinette J. Piaggio, Katie Erin G. Miller, Marjorie D. Matocq, Susan L. Perkins

United States Department of Agriculture Wildlife Services: Staff Publications

Two of the five subspecies of the western big-eared bat, Corynorhinus townsendii, are listed as federally endangered with the remaining three being of conservation concern. Knowing the degree of connectivity among populations would aid in the establishment of sound conservation and management plans for this taxon. For this purpose, we have developed and characterized eight polymorphic microsatellite markers.

Intraspecific Comparison Of Population Structure, Genetic Diversity, And Dispersal Among Three Subspecies Of Townsend’S Big-Eared Bats, Corynorhinus Townsendii Townsendii, C. T. Pallescens, And The Endangered C. T. Birginianus, Antoinette J. Piaggio, Kirk W. Navo, Craig W. Stihler

United States Department of Agriculture Wildlife Services: Staff Publications

Townsend’s big-eared bat, Corynorhinus townsendii, is distributed broadly across western North America and in two isolated, endangered populations in central and eastern United States. There are five subspecies of C. townsendii; C. t. pallescens, C. t. australis, C. t. townsendii, C. t. ingens, and C. t. virginianus with varying degrees of concern over the conservation status of each. The aim of this study was to use mitochondrial and microsatellite DNA data to examine genetic diversity, population differentiation, and dispersal of three C. townsendii subspecies. C. t. virginianus is found in isolated populations in the eastern United States and …

Experimental Infection Of Cliff Swallows (Petrochelidon Pyrrhonota) With Varying Doses Of West Nile Virus, Paul T. Oesterle, Nicole M. Nemeth, Kaci K. Vandalen, Heather Sullivan, Kevin T. Bentler, Ginger R. Young, Robert G. Mclean, Larry Clark, Cynthia Smeraski, Jeffrey S. Hall

United States Department of Agriculture Wildlife Services: Staff Publications

Cliff swallows (Petrochelidon pyrrhonota) were inoculated with differing doses of West Nile virus (WNV) to evaluate their potential role as reservoir hosts in nature. Swallows often nest in large colonies in habitats and months associated with high mosquito abundance and early WNV transmission in North America. Additionally, cliff swallow diet consists of insects, including mosquitoes, leading to an additional potential route of WNV infection. The average peak viremia titer among infected cliff swallows was 10^6.3 plaque-forming units (PFU)/mL serum and the reservoir competence index was 0.34. There was no correlation between dose and probability of becoming infected …

Capturing And Handling Wild Animals, Sanford D. Schemnitz, Gordon R. Batcheller, Matthew J. Lovallo, H. Bryant White, Michael W. Fall

United States Department of Agriculture Wildlife Services: Staff Publications

The art of capturing wild animals for food and clothing is as old as human existence on earth. However, in today’s world, reasons for catching wild species are more diverse. Millions of wild animals are captured each year as part of damage and disease control programs, population regulation activities, wildlife management efforts, and research studies. Many aspects of animal capture, especially those associated with protected wildlife species, are highly regulated by both state and federal governmental agencies. Animal welfare concerns are important regardless of the reason for capture. In addition, efficiency (the rate at which a device or system catches …

Deer Responses To Repellent Stimuli, Bruce A. Kimball, Jimmy D. Taylor Ii, Kelly R. Perry, Christina Capelli

United States Department of Agriculture Wildlife Services: Staff Publications

Four repellents representing different modes of action (neophobia, irritation, conditioned aversion, and flavor modification) were tested with captive white-tailed deer in a series of two-choice tests. Two diets differing significantly in energy content were employed in choice tests so that incentive to consume repellent-treated diets varied according to which diet was treated. When the high energy diet was treated with repellents, only blood (flavor modification) and capsaicin (irritation) proved highly effective. Rapid habituation to the odor of meat and bone meal (neophobia) presented in a sachet limited its effectiveness as a repellent under conditions with a high feeding motivation. Thiram, …

Feasibility Of Infectious Prion Digestion Using Mild Conditions And Commercial Subtilisin, John L. Pilon, Paul B. Nash, Terry Arver, Don Hoglund, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Two serine protease enzymes, subtilisin 309 and subtilisin 309-v,were used to digest brain homogenates containing high levels of prion infectivity using mildly alkaline conditions to investigate prion decontamination methods. To establish that PrP^res infectivity was eliminated, we utilized the Rocky Mountain Laboratory (RML) mouse-adapted scrapie model system for bioassay. Only one digestion condition (subtilisin 309 at 138mAU/ml, 55^◦C and 14 h digestion time pH 7.9) was considered to be highly relevant statistically (P < 0.001) compared to control, with 52% of challenged mice surviving until the end of the study period. In contrast, treatment of PrP^res by autoclaving at 134^◦C or treatment with hypochlorite at a concentration of 20,000ppm completely protected mice from prionosis. Further, in …

Oral Rabies Vaccination In North America: Opportunities, Complexities, And Challenges, Dennis Slate, Timothy P. Algeo, Kathleen M. Nelson, Richard B. Chipman, Dennis Donovan, Jesse D. Blanton, Michael Niezgoda, Charles E. Rupprecht

United States Department of Agriculture Wildlife Services: Staff Publications

Steps to facilitate inter-jurisdictional collaboration nationally and continentally have been critical for implementing and conducting coordinated wildlife rabies management programs that rely heavily on oral rabies vaccination (ORV). Formation of a national rabies management team has been pivotal for coordinated ORV programs in the United States of America. The signing of the North American Rabies Management Plan extended a collaborative framework for coordination of surveillance, control, and research in border areas among Canada, Mexico, and the US. Advances in enhanced surveillance have facilitated sampling of greater scope and intensity near ORV zones for improved rabies management decision-making in real time. …

Mammalian Hazards At Small Airports In Indiana: Impact Of Perimeter Fencing, Travis Default, Jacob Kubel, David Glista, Olin E. Rhodes Jr.

United States Department of Agriculture Wildlife Services: Staff Publications

Fences are used at many airports and small airfields to exclude wildlife from entering critical areas. However, not all fences exclude hazardous mammals reliably, and effective fences can be too expensive for small airports to purchase and maintain. In this study, we evaluated fencing at 10 small airports in Indiana and documented the presence and relative abundance of wildlife within airport boundaries using remote cameras and spotlight surveys. Only 4 airports were completely fenced, and four were Odocoileus virginianus) or coyotes (Canis latrans) at nine of the airports with remote cameras and during spotlight surveys. There were fewer …

Historic And Recent Distributions Of Elk In Nebraska, Kent A. Fricke, Michael A. Cover, Scott E. Hygnstrom, Hugh H. Genoways, Scott R. Groepper, Kit Hams, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Elk (Cervus elaphus) were historically found throughout North America but were extirpated from Nebraska and much of the Great Plains in the 1880s due to consumptive uses by settlers, miners, market hunters, and others. Elk began to reappear in Nebraska in the 1950s and 1960s, and established a stable, nonmigratory population that currently consists of seven herds and an estimated 1,400 individuals throughout western and central Nebraska. The reappearance and subsequent persistence of elk in Nebraska suggests there is adequate habitat to support a self-sustaining population. The general movement of elk eastward may lead to an eventual statewide …

Foods Scraps Composting And Vector Control, Bradley F. Blackwell, Thomas W. Seamans

United States Department of Agriculture Wildlife Services: Staff Publications

Nontraditional waste management facilities, particularly new projects to compost food scraps, are becoming more common because of national and state initiatives to promote recycling and extend landfill capacities. In fact, food waste is the third largest component of generated waste by weight, following yard trimmings and corrugated boxes. The U.S. Department of Agriculture (USDA) estimates that each American disposes of 1.3 pounds of food waste daily or nearly 474 pounds annually. While there is a clear need to recycle food waste, the location of waste management facilities and national initiatives on waste management are increasingly controversial, partly because of potential …

Physiological Effects Of Gonadotropin-Releasing Hormone Immunocontraception On White-Tailed Deer, Paul D. Curtis, Milo E. Richmond, Lowell A. Miller, Fred W. Quimby

United States Department of Agriculture Wildlife Services: Staff Publications

Before immunocontraceptives can be considered safe to use on wildlife species, potential health risks should be assessed. Gonadotropin-releasing hormone (GnRH) immunocontraceptive has successfully reduced fertility of white-tailed deer (Odocoileus virginianus); however, associated deer physiology has rarely been examined. We conducted gross necropsy examinations, histology, and blood chemistry comparisons on euthanized deer previously vaccinated with immunogenic GnRH (n = 18 females and n = 4 males), or left as untreated controls (n = 7 females and n = 6 males). Granulomas were found at injection sites of most deer, even 3 years post-treatment. There were no significant differences in …

Gnrh Immunocontraception Of Male And Female White-Tailed Deer Fawns, Lowell A. Miller, James P. Gionfriddo, Jack C. Rhyan, Kathleen A. Fagerstone, Donald C. Wagner, Gary J. Killian

United States Department of Agriculture Wildlife Services: Staff Publications

Immunocontraceptive vaccines based on gonadotropin-releasing hormone (GnRH) have been tested in adult white-tailed deer (Odocoileus virginianus), but their effects on fawns are unknown. The purpose of this study was to determine if early immunization against GnRH would induce a long-lasting immune response in fawns, and if it would delay or prevent sexual development. We gave primary and subsequent booster injections of a KLH-GnRH/Freund’s vaccine to 6 male and 6 female fawns. This vaccine contained the same active ingredients as GonaCon™ vaccine, but it contained Freund’s adjuvant instead of AdjuVac™ adjuvant. Two 450-μg injections were given 1 month apart …

Just Green Iguanas? The Associated Costs And Policy Implications Of Exotic Invasive Wildlife In South Florida, Arthur Sementelli, Henry T. Smith, Walter E. Meshaka Jr., Richard M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive exotic species have begun to emerge as a policy issue at the federal, state, and local levels. Although invasive species are often understood as a function of the damage they cause to localized ecosystems, this study diverges by discussing the infrastructural damage caused by an invasive exotic species, the green iguana (Iguana iguana). Specifically, the authors discuss the magnitude and scope of damage caused by iguana burrows on canals in southern Florida and offer policy recommendations to move discussions of this potentially disastrous public works issue forward.

Estimating Population Size Of Mexican Wolves Noninvasively (Arizona), C. A. Cariappa, Warren Ballard, Stewart W. Breck, Antoinette J. Piaggio, Melissa Neubaum

United States Department of Agriculture Wildlife Services: Staff Publications

Monitoring wolf abundance is a significant problem confronting biologists coordinating the recovery of the Mexican wolf (Canis lupus baileyi) population in the Blue Range Wolf Recovery Area (BRWRA) in Arizona and New Mexico (Figure 1). Thus far, radiotelemetry has been a satisfactory method. However, collaring and tracking more wolves in the expanding population is expensive. The development of a cost-effective method to estimate Mexican wolf populations will assist the long-term management and recovery of wolves.

We are attempting species and individual identification using DNA extracted from wolf scat because scat is both readily available and easy to collect …

Overwintering Site Selection By Short-Horned Lizards (Phrynosoma Hernandesi) In Northeastern Colorado, Tom Mathies, Daniel J. Martin

United States Department of Agriculture Wildlife Services: Staff Publications

Radio telemetry was used to track 16 adult Short-Horned Lizards (Phrynosoma hernandesi) to their individual overwintering sites on the Central Plains Experimental Range (CPER) in Weld County, Colorado. Above-ground habitat characteristics of overwintering sites and randomly selected points within the study area were assessed. All individuals entered overwintering between 29 August and 19 September with a mean estimated entrance date of 7 September. Arrival of the first subzero nighttime air temperatures occurred shortly thereafter on 16 September. No lizard left its normal area of use to overwinter, and there was no tendency to aggregate. Lizards did not necessarily …

Livestock Protection Dogs For Deterring Deer From Cattle And Feed, Kurt C. Vercauteren, Michael J. Lavelle, Gregory Phillips

United States Department of Agriculture Wildlife Services: Staff Publications

Disease transmission between wildlife and livestock is a worldwide issue. Society needs better methods to prevent interspecies transmission to reduce disease risks. Producers have successfully used livestock protection dogs (LPDs) for thousands of years to reduce predation. We theorized that LPDs raised and bonded with cattle could be used to also reduce risk of bovine tuberculosis (Myobacterium bovis; TB) transmission between white-tailed deer (Odocoileus virginianus) and cattle by minimizing contact between the 2 species and use of cattle feed by deer. We evaluated 4 LPDs over 5 months, utilizing 2 data collection methods (direct observation and …

Passive Immunity To West Nile Virus Provides Limited Protection In A Common Passerine Species, Nicole M. Nemeth, Paul T. Oesterle, Richard A. Bowen

United States Department of Agriculture Wildlife Services: Staff Publications

Passerine birds have played an important role in the establishment, maintenance, and spread of West Nile virus (WNV) in North America, and some are susceptible to WNV-associated mortality. Characterization of passive transfer of anti-WNV antibodies in passerines is important to understanding transmission and demographic effects of WNV on wild birds. We showed passively acquired maternal antibodies to WNV in the house sparrow (Passer domesticus). Although all seropositive females (N = 18) produced antibody-positive egg yolks, only 20% of seropositive mothers (3/15) produced seropositive chicks. The estimated average half-life of maternal antibodies in chick sera was 3 days, …

Skunk Rabies In California (1992–2003)—Implications For Oral Rabies Vaccination, Ray T. Sterner, Ben Sun, Jean B. Bourassa, Robert L. Hale, Stephanie A. Shwiff, Michele T. Jay, Dennis Slate

United States Department of Agriculture Wildlife Services: Staff Publications

Skunk-variant rabies is endemic in California (United States), and the development of oral vaccines and baits to vaccinate skunks is in progress. In 2003, the California Department of Public Health (CDPH) began to quantify the impacts of skunk-variant rabies and to assess the feasibility of using oral rabies vaccination (ORV) as a containment measure. The CDPH rabies case data for skunks were spatially depicted and analyzed using a geographic information system. Statewide, rabid skunks (1992–2003) primarily occurred in seven physiographic regions: Central Coast, North Coast, North Sierra, Sacramento Valley, San Francisco Bay and Delta, San Joaquin Valley, and South Sierra. …

Food Color, Flavor, And Conditioned Avoidance Among Red-Winged Blackbirds, Scott J. Werner, Bruce A. Kimball, Frederick D. Provenza

United States Department of Agriculture Wildlife Services: Staff Publications

The relationship between food flavors and postingestive feedback enables mammalian herbivores to procure nutrients and avoid toxins within ever-changing environments. We conducted four experiments with red-winged blackbirds (Agelaius phoeniceus) in captivity to determine the relative roles of color and flavor cues paired with negative postingestive feedback. We first conducted baseline tests to assess preferences for colors and flavors. All blackbirds preferred red- to blue-colored food, and they preferred umami- (L-alanine) flavored to bitter/astringent food (tannic acid). We observed no difference in consumption of salty (NaCl) vs sour (citric acid) foods during baseline tests (i.e., neutral flavors). We then …

Nicarbazin Bait Reduces Reproduction By Pigeons (Columba Livia), Michael L. Avery, Kandy L. Keacher, Eric A. Tillman

United States Department of Agriculture Wildlife Services: Staff Publications

Development of effective methods for reducing populations of overabundant nuisance bird species continues to challenge wildlife biologists. Reproductive inhibition, although conceptually pleasing, has been difficult to implement because of the lack of a safe, approved avian contraceptive. Recently, however, nicarbazin received regulatory approval in the United States for use as a bait to decrease hatchability of resident Canada goose (Branta canadensis) and feral pigeon (Columba livia) eggs. In anticipation of the feral pigeon registration, we evaluated efficacy by exposing captive pairs of nesting pigeons to nicarbazin bait for 4 h daily. Egg production was unaffected, but …

Evaluation Of Aerial Cluster Sampling Of Double-Crested Cormorants On Aquaculture Ponds In Mississippi, Brian S. Dorr, Loren W. Burger Jr., Scott C. Barras

United States Department of Agriculture Wildlife Services: Staff Publications

Concern over increasing numbers of double-crested cormorants (Phalacrocorax auritus) and their impacts on channel catfish (Ictalurus punctatus) aquaculture has resulted in increased need for quantitative information to develop and evaluate depredation management efforts. We evaluated aerial surveys in a stratified cluster sampling (SCS) design to estimate and monitor abundance of cormorants on catfish aquaculture ponds in the Yazoo River Basin of Mississippi, USA (hereafter Yazoo Basin). Twice monthly abundance estimates and coefficient of variation during winter averaged 8,128 (n = 29, SE = 1,233) and 33% (n = 29, SE = 0.02), respectively. Counts of cormorants …

Foot-And-Mouth Disease In North American Bison (Bison Bison) And Elk (Cervus Elaphus Nelsoni): Susceptibility, Intra- And Interspecies Transmission, Clinical Signs, And Lesions, Jack Rhyan, Ming Deng, He Wang, Gordon Ward, Thomas Gidlewski, Matthew Mccollum, Samia Metwally, Thomas Mckenna, Sherrilyn Wainwright, Antonio Ramirez, Charles Mebus, Mo Salman

United States Department of Agriculture Wildlife Services: Staff Publications

There is limited information about the pathogenesis and epidemiology of foot-andmouth disease (FMD) in North American bison (Bison bison) or elk (Cervus elaphus nelsoni). In these two experimental infection studies, we compared the susceptibilities of bison and elk to FMD virus (FMDV), respectively, with that of cattle; determined whether intra- and interspecies transmission could occur in bison and cattle, and elk and cattle; determined suitability of conventional available laboratory tests to detect FMDV infection in bison and elk; and investigated whether bison or elk are efficient long-term carriers of FMDV. In both studies, after a period …

Mammalian Visitation To Candidate Feral Swine Attractants, Tyler A. Campbell, David B. Long

United States Department of Agriculture Wildlife Services: Staff Publications

Few data exist regarding suitable feral swine (Sus scrofa) attractants in the United States. We compared species-specific visitation and contact rates of mammals to 11 candidate feral swine attractants at scent stations using motion-sensing digital photography to identify promising attractants. We found feral swine had greater visitation rates to apple and strawberry stations than to control stations. We recommend managers consider using strawberry attractants for feral swine-specific applications. If, however, a general feral swine attractant is needed, then apple, berry, or caramel attractants may perform well.

Avoidance Of Hydrolyzed Casein By Mice, Kristin L. Field, Bruce A. Kimball, Julie A. Mennella, Gary K. Beauchamp, Alexander A. Bachmanov

United States Department of Agriculture Wildlife Services: Staff Publications

When casein, a milk protein, is hydrolyzed, it renders human foods that contain it (e.g., hypoallergenic infant formula, cheeses) distasteful to many people. This rejection of hydrolyzed casein (HC)-containing foods has recently been found to also occur in a non-human species (deer, Odocoileus spp.). Identifying other animals that avoid HC would facilitate understanding how and why HC-containing food is often rejected. This study determined whether HC-containing food is avoided by Mus musculus and whether consumption patterns were sensitive to testing conditions, specifically food form (powder, pellet or dough) and food access (ad libitum or 1.5 h/day following 6 h …

Breeding Red-Winged Blackbird Response To Conspecific Models Placed In Pre-Copulatory Position: Implications For Reproductive Control, Laurel L. Moulton, George M. Linz, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

Sunflower producers in the northern Great Plains are annually plagued by feeding flocks of blackbirds, especially red-winged blackbirds (RWBL). Increased sunflower production and concomitant human-blackbird conflicts have prompted sunflower producers to demand that management strategies be developed to reduce the annual crop losses estimated at ≥ $10 million (Linz et al. 1996). Past techniques aimed at reducing blackbird damage have had varying degrees of success and the annual loss of sunflower remains the same (Peer et al. 2002). Thus, there is a need for new innovative approaches to managing blackbird damage.

One approach is to find non-lethal species-specific methods of …

Evaluation Of Stop-Level Vs. Route-Level Breeding Bird Survey Counts For Modeling The Influence Of Land Use And Climate On Breeding Blackbird Abundance In North Dakota, Michelle L. Petersen, George M. Linz, Greg Forcey, Wayne Thogmartin, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

The Red-winged Blackbird (Agelaius phoeniceus), Yellow-headed Blackbird (Xanthocephalus xanthocephalus), and Common Grackle (Quiscalus quiscula) are the three most abundant blackbird species (Icteridae) found in North Dakota and comprise almost 10% of its avian population (Stewart and Kantrud 1972). Blackbird abundance combined with their food habitats make them significant agricultural pests on sunflower. Cost estimates for blackbird damage to sunflower in the North Dakota are likely over $10 million dollars annually (Kleingartner, pers. comm). Because of this economic impact blackbirds have on agriculture, it is important to understand land use and climatic factors influencing blackbird …

Development Of Polymorphic Microsatellite Loci For The Common Vampire Bat, Desmodus Rotundus (Chiroptera: Phylostomidae), Antoinette J. Piaggio, John J. Johnston, Susan L. Perkins

United States Department of Agriculture Wildlife Services: Staff Publications

The common vampire bat (Desmodus rotundus) is one of three haematophagous species of bats and the only species in this genus. These New World bats prey on mammals and create significant economic impacts through transmission of rabies in areas where livestock are prevalent. Furthermore, in some portions of their range, it is not uncommon for them to prey upon humans. It is critical to the management of this species and for understanding the spread of bat rabies that detailed studies of D. rotundus population structure be conducted. To further such studies, we have characterized 12 microsatellite loci for …