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Diverse Examples From Managing Invasive Vertebrate Species On Inhabited Islands Of The United States, Richard M. Engeman, Michael L. Avery, Aaron B. Shiels, Are R. Berentsen, Kurt C. Vercauteren, Robert T. Sugihara, Anthony G. Duffiney, Craig S. Clark, John D. Eisemann

United States Department of Agriculture Wildlife Services: Staff Publications

A wide array of sizes, ecosystems, cultures, and invasive wildlife are represented among inhabited islands. Here, six cases from the United States of America (US) are selected to illustrate the high diversity of invasive animal management issues and objectives. We outline the background, define the problems and management objectives. We identify the management approaches and discuss the results and influences as they specifically relate to inhabited islands. The examples are: (1) Gambian giant pouched rats on Grassy Key, Florida; (2) coqui frogs on Kaua’i, Hawai’i; (3) feral swine on Cayo Costa Island, Florida; (4) rodents and monitor lizards on Cocos …

How Behavior Of Nontarget Species Affects Perceived Accuracy Of Scat Detection Dog Surveys, Karen E. Dematteo, Linsey W. Blake, Julie K. Young, Barbara Davenport

United States Department of Agriculture Wildlife Services: Staff Publications

Detection dogs, specially trained domestic dogs (Canis familiaris), have become a valuable, noninvasive, conservation tool because they remove the dependence of attracting species to a particular location. Further, detection dogs locate samples independent of appearance, composition, or visibility allowing researchers to collect large sets of unbiased samples that can be used in complex ecological queries. One question not fully addressed is why samples from nontarget species are inadvertently collected during detection dog surveys. While a common explanation has been incomplete handler or dog training, our study aimed to explore alternative explanations. Our trials demonstrate that a scat’s genetic …

Plumage Changes In Double-Crested Cormorants (Phalacrocorax Auritus) Within The Breeding Season: The Risks Of Aging By Plumage, Jennifer E. Chastant, D. Tommy King

United States Department of Agriculture Wildlife Services: Staff Publications

Scant attention has been given to the molting patterns of known-age Double-crested Cormorants (Phalacrocorax auritus). In general, subadult individuals are identified with a tan, buffy or mottled chest, and adults are identified with a black chest. While studying Double-crested Cormorant population dynamics in Ontario, Canada, with known-age birds, it was noted that the plumage of many (> 75%) breeding adults changed from black to heavily mottled during the course of the breeding season. No pattern with age was observed; plumage changed in equal proportions for all ages from 2-year-olds to 7-year-olds. A similar but reverse pattern has been …

State Management Of Human– Wildlife Conflicts, Kurt C. Vercauteren, Daniel Hirchert, Scott Hygnstrom

United States Department of Agriculture Wildlife Services: Staff Publications

Many positive experiences are associated with wildlife, from passively watching animals in our backyards to actively hunting in publicly owned forests. Unfortunately, wildlife can be a double- edged sword. Human– wildlife conflicts are pervasive in society, and nearly all segments—wealthy and in need, urban and rural, east and west—can experience problems with wildlife. Agricultural producers lose an estimated $45 billion each year as a result of crop and livestock damage caused by big game, predators, waterfowl, and other wildlife species (Conover 2002). Row crops, forages, rangeland, fruits, vegetables, ornamentals, turf, and livestock are susceptible to damage by wildlife at various …

Behavioral Differences Following Ingestion Of Large Meals And Consequences For Management Of A Harmful Invasive Snake: A Field Experiment, Shane R. Siers, Amy A. Yackel Adams, Robert N. Reed

United States Department of Agriculture Wildlife Services: Staff Publications

Many snakes are uniquely adapted to ingest large prey at infrequent intervals. Digestion of large prey is metabolically and aerobically costly, and large prey boluses can impair snake locomotion, increasing vulnerability to predation. Cessation of foraging and use of refugia with microclimates facilitating digestion are expected to be strategies employed by free-ranging snakes to cope with the demands of digestion while minimizing risk of predation. However, empirical observations of such submergent behavior from field experiments are limited. The brown treesnake (Serpentes: Colubridae: Boiga irregularis) is a nocturnal, arboreal, colubrid snake that was accidentally introduced to the island of Guam, …

Estimating The Economic Impact Of Canine Rabies To Viet Nam 2005–2014, Stephanie A. Shwiff, Vienna R. Brown, Thu Trang Dao, Julie Elser, Hoang Xuan Trung, Nguyen Ngoc Tien, Nguyen Thi Huong, Nguyen Thi Thanh Huong, Arthorn Riewpaiboon, Karina Ernst, Steven Shwiff, David Payne

United States Department of Agriculture Wildlife Services: Staff Publications

The global economic impact of canine rabies has been estimated by several studies. Asia bears a disproportionate burden of this zoonosis due to high levels of human deaths and rates of post-exposure prophylaxis (PEP), but low investment in preventative dog vaccination. The same factors that cause rabies to burden much of Asia are also present in Viet Nam. This study estimated the economic burden of canine rabies in a societal perspective including direct and indirect cost of rabies in dogs, livestock, and humans. Using data collected from personal interviews, published literature, published and supplementary reports, and primary data collection, we …

Quantification Of Avian Hazards To Military Aircraft And Implications For Wildlife Management, Morgan Pfeiffer, Bradley F. Blackwell, Travis L. Devault

United States Department of Agriculture Wildlife Services: Staff Publications

Collisions between birds and military aircraft are common and can have catastrophic effects. Knowledge of relative wildlife hazards to aircraft (the likelihood of aircraft damage when a species is struck) is needed before estimating wildlife strike risk (combined frequency and severity component) at military airfields. Despite annual reviews of wildlife strike trends with civil aviation since the 1990s, little is known about wildlife strike trends for military aircraft. We hypothesized that species relative hazard scores would correlate positively with aircraft type and avian body mass. Only strike records identified to species that occurred within the U.S. (n = 36,979) …

Fertility Control For Managing Free-Roaming Feral Cattle In Hong Kong, Giovanna Massei, Ka-Kei Koon, Siu-Iun Law, Matt Gomm, Darcy S. O. Mora, Rebecca Callaby, Kate Palphramand, Douglas C. Eckery

United States Department of Agriculture Wildlife Services: Staff Publications

Human-wildlife conflicts are increasing worldwide. For instance, growing numbers of free-roaming feral cattle in Hong Kong are causing traffic accidents and damaging crops. Public antipathy towards lethal methods to manage wildlife has promoted research into alternative options, such as fertility control. The aims of this study were to assess the potential side effects and effectiveness of the injectable immunocontraceptive vaccine GonaCon on free-roaming feral cattle in Hong Kong. Sixty female cattle were captured and randomly assigned to treatment or control groups. Treatment animals were administered one dose of GonaCon, followed by a booster dose 3–6 months later. Control animals were …

Roads Do Not Increase Carrion Use By A Vertebrate Scavenging Community, Jacob E. Hill, Travis L. Devault, James C. Beasley, Olin E. Rhodes Jr., Jerrold L. Belant

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife-vehicle collisions introduce a considerable amount of carrion into the environment, but scavenger use of this resource has not been extensively investigated. Scavengers may use roads for reliable foraging opportunities, but might also use roads for other purposes and encounter carrion opportunistically. We examined scavenging of carrion along linear features by placing 52 rabbit carcasses in each of three treatments in forested habitat during winter (Dec 2016-Mar 2017) in South Carolina, USA: roads, power line clearings (linear feature with fewer carcasses than roads due to lack of road kill), and forest interior. We used motion-activated cameras to compare arrival times …

Evaluating An Alleged Mimic Of The Monarch Butterfly: Neophasia (Lepidoptera: Pieridae) Butterflies Are Palatable To Avian Predators, Dale A. Halbritter, Johnalyn M. Gordon, Kandy L. Keacher, Michael L. Avery, Jaret C. Daniels

United States Department of Agriculture Wildlife Services: Staff Publications

Some taxa have adopted the strategy of mimicry to protect themselves from predation. Butterflies are some of the best representatives used to study mimicry, with the monarch butterfly, Danaus plexippus (Lepidoptera: Nymphalidae) a well-known model. We are the first to empirically investigate a proposed mimic of the monarch butterfly: Neophasia terlooii, the Mexican pine white butterfly (Lepidoptera: Pieridae). We used captive birds to assess the palatability of N. terlooii and its sister species, N. menapia, to determine the mimicry category that would best fit this system. The birds readily consumed both species of Neophasia and a palatable control species but …

Cross-Fostering As A Conservation Tool To Augment Endangered Carnivore Populations, Eric M. Gese, William T. Waddell, Patricia A. Terletzky, Chris F. Lucash, Scott R. Mclellan, Susan K. Behrns

United States Department of Agriculture Wildlife Services: Staff Publications

Cross-fostering offspring with nonbiological parents could prove useful to augment populations of endangered carnivores. We used cross-fostering to augment captive-born and wild-born litters for the endangered red wolf (Canis rufus). Between 1987 and 2016, 23 cross-fostering events occurred involving captive-born pups fostered into captive litters (n = 8 events) and captive-born pups fostered into wild recipient litters (n = 15 events). Percentage of pups surviving 3 and 12 months was 91.7% for captive-born pups fostered into captive recipient litters. For pups fostered into wild litters, percentage of pups surviving 5 months was > 94% among fostered pups …

Persistence Of Maternal Antibodies To Influenza A Virus Among Captive Mallards (Anas Platyrhynchos), Katherine L. Dirsmith, J. Jeffrey Root, Kevin T. Bentler, Heather J. Sullivan, Andrea B. Liebowitz, Lauren H. Petersen, Hailey E. Mclean, Susan A. Shriner

United States Department of Agriculture Wildlife Services: Staff Publications

Wild waterfowl are maintenance hosts of most influenza A virus (IAV) subtypes and are often the subjects of IAV surveillance and transmission models. While maternal antibodies have been detected in yolks and in nestlings for a variety of wild bird species and pathogens, the persistence of maternal antibodies to IAVs in mallard ducklings (Anas platyrhynchos) has not been previously investigated. Nonetheless, this information is important for a full understanding of IAV transmission dynamics because ducklings protected by maternal antibodies may not be susceptible to infection. In this study, we examined the transfer of IAV-specific maternal antibodies to ducklings. …

Absence Of Native Flower Visitors For The Endangered Hawaiian Mint Stenogyne Angustifolia: Impending Ecological Extinction?, Clare E. Aslan, Christina T. Liang, Aaron B. Shiels, William Haines

United States Department of Agriculture Wildlife Services: Staff Publications

If an organism becomes rare enough that it no longer participates in certain interspecific interactions, it can be said to have become ecologically extinct, even though it is still present. This form of extinction is much less recognized than global extinctions, although it may have ramifications for ecological community function. Here, we describe a case of possible or pending ecological extinction of an endemic Hawaiian plant. We performed over 120 h of systematic flower visitation observations of the endangered Hawaiian mint, Stenogyne angustifolia, in its wild habitat. The robust size and open shape of S. angustifolia flowers, along with their …

Tissue Tropisms Opt For Transmissible Reassortants During Avian And Swine Influenza A Virus Co-Infection In Swine, Xiaojian Zhang, Hailiang Sun, Fred L. Cunningham, Lei Li, Katie Hanson-Dorr, Matthew W. Hopken, Jim Cooley, Li-Ping Long, John A. Baroch, Tao Li, Brandon S. Schmit, Xiaoxu Lin, Alicia K. Olivier, Richard G. Jarman, Thomas J. Deliberto, Xiu-Feng Wan

United States Department of Agriculture Wildlife Services: Staff Publications

Genetic reassortment between influenza A viruses (IAVs) facilitate emergence of pandemic strains, and swine are proposed as a “mixing vessel” for generating reassortants of avian and mammalian IAVs that could be of risk to mammals, including humans. However, how a transmissible reassortant emerges in swine are not well understood. Genomic analyses of 571 isolates recovered from nasal wash samples and respiratory tract tissues of a group of co-housed pigs (influenza-seronegative, avian H1N1 IAV–infected, and swine H3N2 IAV– infected pigs) identified 30 distinct genotypes of reassortants. Viruses recovered from lower respiratory tract tissues had the largest genomic diversity, and those recovered …

Intercanine Width Measurements To Aid Predation Investigations: A Comparison Between Sympatric Native And Non-Native Carnivores In The Mexican Wolf Recovery Area, Tana Verzuh, David L. Bergman, Scott C. Bender, Maggie Dwire, Stewart W. Breck

United States Department of Agriculture Wildlife Services: Staff Publications

Mexican wolves (Canis lupus baileyi) share their range with a number of sympatric carnivores, many of which are a concern to livestock producers because they can prey on livestock. Determining which predator species is responsible for killing livestock is important for determining appropriate management actions and for the conservation of Mexican wolves. A variety of information can be used to decipher which carnivore species was responsible for making a kill, and mandibular (upper) and maxillary (lower) intercanine width measurements (i.e., bite mark analysis) can aid this process. No research has been conducted to validate the usefulness of bite …

Parental Habituation To Human Disturbance Over Time Reduces Fear Of Humans In Coyote Offspring, Christopher J. Schell, Julie K. Young, Elizabeth V. Lonsdorf, Rachel M. Santymire, Jill M. Mateo

United States Department of Agriculture Wildlife Services: Staff Publications

A fundamental tenet of maternal effects assumes that maternal variance over time should have discordant consequences for offspring traits across litters. Yet, seldom are parents observed across multiple reproductive bouts, with few studies considering anthropogenic disturbances as an ecological driver of maternal effects. We observed captive coyote (Canis latrans) pairs over two successive litters to determine whether among‐litter differences in behavior (i.e., risk‐taking) and hormones (i.e., cortisol and testosterone) corresponded with parental plasticity in habituation. Thus, we explicitly test the hypothesis that accumulating experiences of anthropogenic disturbance reduces parental fear across reproductive bouts, which should have disparate phenotypic …

American Black Bear Den-Site Selection And Characteristics In An Urban Environment, Toryn L. J. Schafer, Stewart W. Breck, Sharon Baruch-Mordo, David L. Lewis, Kenneth R. Wilson, Julie S. Mao, Thomas L. Day

United States Department of Agriculture Wildlife Services: Staff Publications

Selection of den sites is a crucial aspect of American black bear (Ursus americanus) life history. High-quality dens provide thermal insulation, protection from disturbance, suitable environment for parturition and cub development, and proximity to available forage upon emergence. Black bears are increasingly coexisting with people in human-dominated landscapes; however, little is known about whether urban environments influence characteristics of dens and den site selection. Our objective was to determine the effect of housing density (a proxy for human activity and availability of anthropogenic resources) on selection of den sites in years of good and poor natural forage.We additionally …

Viral Shedding Of Clade 2.3.4.4 H5 Highly Pathogenic Avian Influenza A Viruses By American Robins, J. Jeffrey Root, Angela M. Bosco-Lauth, Nicole L. Marlenee, Richard A. Bowen

United States Department of Agriculture Wildlife Services: Staff Publications

American robins (Turdus migratorius) are commonly associated with farmsteads in the United States and have shown previous evidence of exposure to an H5 avian influenza A virus (IAV) near a poultry production facility affected by a highly pathogenic (HP) H5 virus in Iowa, USA during 2015. We experimentally infected American robins with three clade 2.3.4.4 HP H5 viruses (H5N2 and H5N8). A total of 22/24 American robins shed virus, and all three strains were represented. The highest virus titres shed were 10^4.3, 10^4.3 and 10^4.8 PFU/ml, associated respectively with viruses isolated from poultry, a …

Social Conformity Affects Experimental Measurement Of Boldness In Male But Not Female Monk Parakeets (Myiopsitta Monachus), Kaan Kerman, Kathryn E. Sieving, Colette St. Mary, Michael L. Avery

United States Department of Agriculture Wildlife Services: Staff Publications

The standard approach for characterizing boldness rarely considers the influence of social environment on the expression of boldness in group-living animals. We studied a wild-caught, captive population of monk parakeets (Myiopsitta monachus) to investigate the impact of conspecific presence on boldness — a personality trait in monk parakeets — in a controlled environment. We quantified seven boldness metrics across three types of behavioural assay: novel object, emergence, and predator exposure tests in the presence of a companion pair of flock mates. Because of the high degree of sociality in this species, we hypothesized that the presence of companion …

Costs And Effectiveness Of Damage Management Of An Overabundant Species (Sus Scrofa) Using Aerial Gunning, Amy J. Davis, Bruce Leland, Michael Bodenchuk, Kurt C. Vercauteren, Kim M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

Context. Management of overabundant or invasive species is a constant challenge because resources for management are always limited and relationships between management costs, population density and damage costs are complex and difficult to predict. Metrics of management success are often based on simple measures, such as counts, which may not be indicative of impacts on damage reduction or cost-effectiveness under different management plans.

Aims. The aims of this study were to evaluate the effectiveness of aerial gunning for the management of wild pigs (Sus scrofa), and to evaluate how cost-effectiveness would vary under different relationships between levels of …

Accounting For Observation Processes Across Multiple Levels Of Uncertainty Improves Inference Of Species Distributions And Guides Adaptive Sampling Of Environmental Dna, Amy J. Davis, Kelly E. Williams, Nathan P. Snow, Kim M. Pepin, Antoinette J. Piaggio

United States Department of Agriculture Wildlife Services: Staff Publications

Understanding factors that influence observation processes is critical for accurate assessment of underlying ecological processes. When indirect methods of detection, such as environmental DNA, are used to determine species presence, additional levels of uncertainty from observation processes need to be accounted for. We conducted a field trial to evaluate observation processes of a terrestrial invasive species (wild pigs‐ Sus scrofa) from DNA in water bodies. We used a multi‐scale occupancy analysis to estimate different levels of observation processes (detection, p): the probability DNA is available per sample (θ), the probability of capturing DNA per extraction ( …

Evaluating Lethal And Nonlethal Management Options For Urban Coyotes, Stewart W. Breck, Sharon A. Poessel, Mary Ann Bonnell

United States Department of Agriculture Wildlife Services: Staff Publications

Human–coyote (Canis latrans) conflict in urban environments is a growing issue in cities throughout the United States, with the primary problem being the development of problem individuals that are overly bold and aggressive with people and pets. Little research has focused on management options to deal with this conflict. We better define lethal and nonlethal management strategies associated with proactive and reactive management of coyotes with an emphasis on management of problem individuals. We then provide data from research in the Denver Metropolitan Area (DMA), Colorado, USA that focused on reactive lethal removal of problem coyotes and reactive …

Using Resident-Based Hazing Programs To Reduce Human–Coyote Conflicts In Urban Environments, Mary Ann Bonnell, Stewart W. Breck

United States Department of Agriculture Wildlife Services: Staff Publications

The concept of hazing (aversive conditioning) is often promoted as a tool for reducing human–coyote (Canis latrans) conflicts in urban environments. Little scientific evidence exists on the effectiveness of hazing, particularly hazing applied by residents (i.e., community-level hazing). Wildlife professionals question if residents will properly and consistently apply hazing techniques and if hazing impacts coyote behavior over short- and long-term periods. We describe 2 separate efforts designed to encourage residents to haze coyotes in the Denver Metro Area, Colorado, USA: a citizen science program and an open space hazing trial. Both efforts were intended to be management techniques …

Double-Crested Cormorants: Too Much Of A Good Thing?, Brian S. Dorr, David G. Fielder

United States Department of Agriculture Wildlife Services: Staff Publications

For centuries, people have viewed double-crested cormorants Phalacrocorax auritus negatively, and human persecution coupled with environmental contamination severely reduced numbers of cormorants throughout North America. Shifts in paradigms for management of our natural resources resulted in reductions in environmental contaminants and regulatory protection of cormorants, allowing for an amazing population resurgence of this adaptable fish-eating bird. However, for cormorants, as with some other native wildlife species the populations of which have rebounded due to conservation efforts, there have been cormorant– societal conflicts with respect to commercial and natural resources such as aquaculture and sport fisheries. Increasing resource conflicts caused cormorants …

Clearing Muddied Waters: Capture Of Environmental Dna From Turbid Waters, Kelly E. Williams, Kathryn P. Huyvaert, Antoinette J. Piaggio

United States Department of Agriculture Wildlife Services: Staff Publications

Understanding the differences in efficiencies of various methods to concentrate, extract, and amplify environmental DNA (eDNA) is vital for best performance of eDNA detection. Aquatic systems vary in characteristics such as turbidity, eDNA concentration, and inhibitor load, thus affecting eDNA capture efficiency. Application of eDNA techniques to the detection of terrestrial invasive or endangered species may require sampling at intermittent water sources that are used for drinking and cooling; these water bodies may often be stagnant and turbid. We present our best practices technique for the detection of wild pig eDNA in water samples, a protocol that will have wide …

Impact Locations And Damage To Civil And Military Rotary-Wing Aircraft From Wildlife Strikes, Brian E. Washburn, Paul Cisar, Travis L. Devault

United States Department of Agriculture Wildlife Services: Staff Publications

Rotary-wing aircraft (e.g., helicopters and tilt-wing aircraft) are an important component of all U.S. military services and the U.S. civil aviation industry. Our analyses of wildlife strikes to military rotary-wing aircraft, both within the United States and during overseas deployments, as well as civil helicopters, have shown there are important patterns within wildlife strike data for flight operations conducted on airfields and during off -airfield missions. Birds accounted for 93% of the wildlife strikes where the animal was identified, and mammals (primarily bats) accounted for 7%. Wildlife impacted all parts of civil helicopters and military rotary-wing aircraft during strike events; …

Inventory Of Wildlife Use Of Mortality Pits As Feeding Sites: Implications Of Pathogen Exposure, Jeremy W. Ellis, Susan A. Shriner, Hailey E. Mclean, Lauren Petersen, J. Jeffrey Root

United States Department of Agriculture Wildlife Services: Staff Publications

To better understand the use of mortality pits by wildlife and possible pathogen dissemination from the resulting wildlife contact in these areas, we used 8 camera traps on 4 mortality pits in Colorado from June to December 2014 to create a species inventory and establish use estimates for those species. We observed 43 species visiting (in or near) the mortality pits during 1,168 total camera trap days. Of these, 24 species directly interacted with the mortality pits or carcasses contained within them. The most common visitors to mortality pits were raccoons (Procyon lotor), coyotes (Canis latrans), …

Reoccurrence Of Avian Influenza A(H5n2) Virus Clade 2.3.4.4 In Wild Birds, Alaska, Usa, 2016, Dong-Hun Lee, Mia K. Torchetti, Mary Lea Killian, Thomas J. Deliberto, David E. Swayne

United States Department of Agriculture Wildlife Services: Staff Publications

We report reoccurrence of highly pathogenic avian influenza A(H5N2) virus clade 2.3.4.4 in a wild mallard in Alaska, USA, in August 2016. Identification of this virus in a migratory species confirms low-frequency persistence in North America and the potential for re-dissemination of the virus during the 2016 fall migration.

Cross-Species Transmission Potential Between Wild Pigs, Livestock, Poultry, Wildlife, And Humans: Implications For Disease Risk Management In North America, Ryan S. Miller, Steven J. Sweeney, Chris Slootmaker, Daniel A. Grear, Paul A. Di Salvo, Deborah Kiser, Stephanie A. Shwiff

United States Department of Agriculture Wildlife Services: Staff Publications

Cross-species disease transmission between wildlife, domestic animals and humans is an increasing threat to public and veterinary health. Wild pigs are increasingly a potential veterinary and public health threat. Here we investigate 84 pathogens and the host species most at risk for transmission with wild pigs using a network approach. We assess the risk to agricultural and human health by evaluating the status of these pathogens and the co-occurrence of wild pigs, agriculture and humans. We identified 34 (87%) OIE listed swine pathogens that cause clinical disease in livestock, poultry, wildlife, and humans. On average 73% of bacterial, 39% of …

Seasonal Effects Of Wind Conditions On Migration Patterns Of Soaring American White Pelican, Javier Gutierrez Illan, Guiming Wang, Fred L. Cunningham, D. Tommy King

United States Department of Agriculture Wildlife Services: Staff Publications

Energy and time expenditures are determinants of bird migration strategies. Soaring birds have developed migration strategies to minimize these costs, optimizing the use of all the available resources to facilitate their displacement. We analyzed the effects of different wind factors (tailwind, turbulence, vertical updrafts) on the migratory flying strategies adopted by 24 satellite-tracked American white pelicans (Pelecanus erythrorhynchos) throughout spring and autumn in North America. We hypothesize that different wind conditions encountered along migration routes between spring and autumn induce pelicans to adopt different flying strategies and use of these wind resources. Using quantile regression and fine-scale atmospheric …