Life Sciences Commons^™

Novel Eurasian Highly Pathogenic Avian Influenza A H5 Viruses In Wild Birds, Washington, Usa, 2014, Hon S. Ip, Mia Kim Torchetti, Rocio Crespo, Paul Kohrs, Paul Debruyn, Kristin G. Mansfield, Timothy Baszler, Lyndon Badcoe, Barbara Bodenstein, Valerie Shearn-Bochsler, Mary Lea Killian, Janice C. Pedersen, Nichole Hines, Thomas Gidlewski, Thomas J. Deliberto, Jonathan M. Sleeman

United States Department of Agriculture Wildlife Services: Staff Publications

The novel Eurasian lineage clade 2.3.4.4 highly pathogenic avian influenza (HPAI) A(H5N8) virus (http://www.who.int/influenza/gisrs_laboratory/h5_nomenclature_clade2344/en/) spread rapidly and globally during 2014, substantially affecting poultry populations. The first outbreaks were reported during January 2014 in chickens and domestic ducks in South Korea and subsequently in China and Japan (1–4), reaching Germany, the Netherlands, and the United Kingdom by November 2014 and Italy in early December 2014 (5). Also in November 2014, a novel HPAI H5N2 virus was reported in outbreaks on chicken and turkey farms in Fraser Valley, British Columbia, Canada (5). This H5N2 influenza virus is a reassortant that contains the …

Increased Diphacinone And Chlorophacinone Metabolism In Previously Exposed Wild Caught Voles, Microtus Californicus, Katherine E. Horak, Steven F. Volker, Christopher M. Campton

United States Department of Agriculture Wildlife Services: Staff Publications

Rodents have been noteworthy pests in agricultural areas for decades. Because rodents impact diverse ecosystems, anticoagulant rodenticides have been heavily used throughout the world to control rodent populations. This continued use has led to the development of resistance to anticoagulant rodenticides in some populations of targeted rodents. Although many studies have investigated the genetic and molecular basis of anticoagulant resistance, few have focused on potential changes in metabolic function of resistant animals. In this study, vole (Microtus californicus, Peale) liver microsome preparations were made from unexposed animals living in areas that had never used anticoagulant rodenticides for either crop protection …

Modeling And Mapping The Probability Of Occurrence Of Invasive Wild Pigs Across The Contiguous United States, Meredith L. Mcclure, Christopher L. Burdett, Matthew L. Farnsworth, Mark W. Lutman, David M. Theobald, Philip D. Riggs, Daniel A. Grear, Ryan S. Miller

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa), also known as wild swine, feral pigs, or feral hogs, are one of the most widespread and successful invasive species around the world. Wild pigs have been linked to extensive and costly agricultural damage and present a serious threat to plant and animal communities due to their rooting behavior and omnivorous diet. We modeled the current distribution of wild pigs in the United States to better understand the physiological and ecological factors that may determine their invasive potential and to guide future study and eradication efforts. Using national-scale wild pig occurrence data reported between 1982 and …

Mechanisms Of Antimicrobial Resistant Salmonella Enterica Transmission Associated With Starling–Livestock Interactions, James C. Carlson, Doreene R. Hyatt, Jeremy W. Ellis, David R. Pipkin, Anna M. Mangan, Michael Russell, Denise S. Bolte, Richard M. Engeman, Thomas J. Deliberto, George M. Linz

United States Department of Agriculture Wildlife Services: Staff Publications

Bird–livestock interactions have been implicated as potential sources for bacteria within concentrated animal feeding operations (CAFO). European starlings (Sturnus vulgaris) in particular are known to contaminate cattle feed and water with Salmonella enterica through their fecal waste.We propose that fecal waste is not the only mechanisms through which starlings introduce S. enterica to CAFO. The goal of this study was to assess if starlings can mechanically move S. enterica. We define mechanical movement as the transportation of media containing S. enterica, on the exterior of starlings within CAFO.We collected 100 starlings and obtained external wash and gastrointestinal tract (GI) samples. …

Evaluating And Validating Abundance Monitoring Methods In The Absence Of Populations Of Known Size: Review And Application To A Passive Tracking Index, Lee R. Allen, Richard M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

Rarely is it possible to obtain absolute numbers in free-ranging populations and although various direct and indirect methods are used to estimate abundance, few are validated against populations of known size. In this paper, we apply grounding, calibration and verification methods, used to validate mathematical models, to methods of estimating relative abundance. To illustrate how this might be done, we consider and evaluate the widely applied passive tracking index (PTI) methodology. Using published data, we examine the rationality of PTI methodology, how conceptually animal activity and abundance are related and how alternative methods are subject to similar biases or produce …

Predator-Induced Renesting And Reproductive Effort In Indigo Buntings: More Work For Less Pay?, Dana L. Morris, John Faaborg, Brian E. Washburn, Joshua J. Millspaugh

United States Department of Agriculture Wildlife Services: Staff Publications

Renesting after nest predation is ultimately an adaptive response to increase productivity in birds. However, renesting also increases reproductive effort to replace lost clutches. We investigated the consequences of this increased reproductive effort by determining whether renesting in female indigo buntings (Passerina cyanea) is associated with a decline in body condition (size-corrected mass) and haematocrit and an increase in stress hormones and whether renesting or maternal body condition is associated with a decline in productivity (clutch size, nestling body condition). Next, because a consequence of multiple renesting attempts is a prolonged breeding season and later timing, we predicted …

Assessment Of Variation Of Nest Survival For Grassland Birds Due To Method Of Nest Discovery, Tara J. Conkling, Jerrold L. Belant, Travis L. Devault, Guiming Wang, James A. Martin

United States Department of Agriculture Wildlife Services: Staff Publications

Capsule Interpretation of nest survival estimates may be improved by incorporating the search method used to locate nests as a covariate.

Aims To compare annual survival estimates for Dickcissel Spiza americana nests and determine if incorporating search method (structured, opportunistic, or behavioural searches) improved model fit.

Methods Dickcissel nests were located using structured, opportunistic, or behavioural searches over three years (2011–2013) in Mississippi, USA. Models were used to estimate daily survival rates (DSRs) and to analyse factors influencing nest survival.

Results DSRs for Dickcissels were best explained by quadratic date, nest age, age found, and year, but incorporating search method …

Impacts Of Colonial Waterbirds On Vegetation And Potential Restoration Of Island Habitats, Christopher R. Ayers, Katie C. Hanson-Dorr, Sadie O'Dell, Charles D. Lovell, Michael L. Jones, Jason R. Suckow, Brian S. Dorr

United States Department of Agriculture Wildlife Services: Staff Publications

Colonial waterbirds have impacted forested island ecosystems throughout their breeding range, changing vegetation, and soil characteristics and bird communities. Our objectives were to (1) determine effects of three levels of colonial waterbird exclusion on overall vegetation diversity and growth, and survival of a candidate restoration species (black elderberry; Sambucus nigra canadensis); (2) investigate effects of different planting techniques on survival and growth of black elderberry; and (3) determine effects of waterbird colonization on soil chemistry. In 2012, we investigated effects of three levels of waterbird exclusion (none control plots [CON]; partial, which excluded waterbirds larger than gulls [PEX]; and …

Tick-Borne Diseases In Syntopic Populations Of Fallow Deer (Dama Dama) And Axis Deer (Axis Axis) In Northern Mexico, Zeferino García-Vázquez, J. Alfonso Ortega-S., Antonio Cantu-Covarruvias, Juan Mosqueda, David G. Hewitt, Randall W. Deyoung, Tyler A. Campbell, Fred C. Bryant

United States Department of Agriculture Wildlife Services: Staff Publications

We harvested 21 fallow deer (Dama dama) and 17 axis deer (Axis axis) in northern Mexico. Two fallow deer were positive for Babesia bigemina and one for Babesia bovis. Amplicons had the expected 170 and 291 base pairs and were identical to B. bigemina (S45366) and B. bovis (M38218), respectively.

Spatially Explicit Modeling Of Blackbird Abundance In The Prairie Pothole Region, Greg M. Forcey, Wayne E. Thogmartin, George M. Linz, Patrick C. Mckann, Shawn M. Crimmins

United States Department of Agriculture Wildlife Services: Staff Publications

Knowledge of factors influencing animal abundance is important to wildlife biologists developing management plans. This is especially true for economically important species such as blackbirds (Icteridae), which cause more than $100 million in crop damages annually in the United States. Using data from the North American Breeding Bird Survey, the National Land Cover Dataset, and the National Climatic Data Center, we modeled effects of regional environmental variables on relative abundance of 3 blackbird species (red-winged blackbird, Agelaius phoeniceus; yellow-headed blackbird, Xanthocephalus xanthocephalus; common grackle, Quiscalus quiscula) in the Prairie Pothole Region of the central United States. We …

Potential For Great Egrets (Ardea Alba) To Transmit A Virulent Strain Of Aeromonas Hydrophila Among Channel Catfish (Ictalurus Punctatus) Culture Ponds, Madison M. Jubirt, Larry A. Hanson, Katie C. Hanson-Dorr, Lorelei Ford, Scott Lemmons, Paul Fioranelli, Fred L. Cunningham

United States Department of Agriculture Wildlife Services: Staff Publications

Aeromonas hydrophila is a gram-negative, rod-shaped, facultative, anaerobic bacterium that is ubiquitous in freshwater and slightly brackish aquatic environments and infects fish, humans, reptiles, and birds. Recent severe outbreaks of disease in commercial channel catfish (Ictalurus punctatus) aquaculture ponds have been associated with a highly virulent A. hydrophila strain (VAH), which is genetically distinct from less-virulent strains. The epidemiology of this disease has not been determined. Given that A. hydrophila infects birds, we hypothesized that fish-eating birds may serve as a reservoir for VAH and spread the pathogen by flying to uninfected ponds. Great Egrets (Ardea alba …

Antibody Response Of Cattle To Vaccination With Commercial Modified Live Rabies Vaccines In Guatemala, Amy T. Gilbert, Lauren Greenberg, David Moran, Marlon Alvarado, Daniel L. Garcia, Leonard Peruski

United States Department of Agriculture Wildlife Services: Staff Publications

Vampire bat rabies is a public and animal health concern throughout Latin America. As part of an ecological study of vampire bat depredation on cattle in southern Guatemala,we conducted a vaccine seroconversion study among three dairy farms. The main objectives of this cross sectional and cohort study were to understand factors associated withbat bites among cattle, to determine whether unvaccinated cattle had evidence of rabies virus exposure and evaluate whether exposure was related to bat bite prevalence, and to assess whether cattle demonstrate adequate seroconversion to two commercial vaccines used in Guatemala. In 2012, baseline blood samples were collected immediately …

Non-Target Species Mortality And The Measurement Of Brodifacoum Rodenticide Residues After A Rat (Rattus Rattus) Eradication On Palmyra Atoll, Tropical Pacific, William C. Pitt, Are R. Berentsen, Aaron B. Shiels, Steven F. Volker, John D. Eisemann, Alexander S. Wegmann, Gregg R. Howald

United States Department of Agriculture Wildlife Services: Staff Publications

The use of rodenticides to control or eradicate invasive rats (Rattus spp.) for conservation purposes has rapidly grown in the past decades, especially on islands. The non-target consequences and the fate of toxicant residue from such rodent eradication operations have not been well explored. In a cooperative effort, we monitored the application of a rodenticide, ‘Brodifacoum 25W: Conservation’, during an attempt to eradicate Rattus rattus from Palmyra Atoll. In 2011, Brodifacoum 25W: Conservation was aerially broadcasted twice over the entire atoll (2.5 km²) at rates of 80 kg/ha and 75 kg/ha and a supplemental hand broadcast application …

Evaluation Of Anthelmintic Fishmeal Polymer Baits For The Control Of Baylisascaris Procyonis In Free-Ranging Raccoons (Procyon Lotor), Timothy J. Smyser, Shylo R. Johnson, Melissa D. Stallard, Ashley K. Mcgrew, L. Kristen Page, Nikki Crider, Lora R. Ballweber, Robert K. Swihart, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Baylisascaris procyonis is a common gastrointestinal parasite of raccoons (Procyon lotor) and is a zoonotic helminth with the potential to cause severe or fatal infection. Raccoons thrive in human-dominated landscapes, and the fecal-oral transmission pathway and lack of effective treatment make B. procyonis a serious threat to public health. The distribution of medicinal baits has emerged as a socially acceptable and cost-effective method for managing disease in free-ranging wildlife. We assessed the suitability of a mass-producible anthelmintic bait for B. procyonis mitigation by evaluating the willingness of free-ranging raccoons to consume anthelmintic baits and determining whether bait consumption …

Collisions Between Eagles And Aircraft: An Increasing Problem In The Airport Environment, Brian E. Washburn, Michael J. Begier, Sandra E. Wright

United States Department of Agriculture Wildlife Services: Staff Publications

Most known fatalities for both Bald Eagles (Haliaeetus leucocephalus) and Golden Eagles (Aquila chrysaetos) are associated with humans (e.g., collisions with vehicles and artificial structures). Notably, the risk of collisions between eagles and aircraft is an increasing problem at civil airports and military airfields. Of the 234 eagle collisions with civil and military aircraft reported to the Federal Aviation Administration, the U.S. Air Force, and the U.S. Navy during 1990–2013, 52% caused damage to the aircraft. During this 23-yr time period, Bald Eagle–aircraft collisions increased by 2200% and Golden Eagle–aircraft collisions increased by 400%. Eagle–aircraft collisions …

Anthraquinone-Based Repellent For Horned Larks, Great-Tailed Grackles, American Crows And The Protection Of California's Specialty Crops, Scott J. Werner, Shelagh T. Deliberto, Anna M. Mangan, Susan E. Pettit, Jeremy W. Ellis, James C. Carlson

United States Department of Agriculture Wildlife Services: Staff Publications

Specialty crops include fresh and dried fruits, vegetables, tree nuts, and horticultural and nursery crops. California accounts for 28% of the specialty crop acreage in the United States of America, including 72% of U.S. lettuce production (Lactuca sativa L.), 27% of U.S. melon production and 100% of U.S. almond production (Prunus dulcis L.). We conducted controlled feeding experiments to evaluate an anthraquinonebased repellent for horned larks (Eremophila alpestris L.), great-tailed grackles (Quiscalus mexicanus Gmelin) and American crows (Corvus brachyrhynchos Brehm) associated with the depredation of California's lettuce, melon and almond crops, respectively.We observed 38-100% feeding …

Prion Amplification And Hierarchical Bayesian Modeling Refine Detection Of Prion Infection, A. Christy Wyckoff, Nathan Galloway, Crystal Meyerett-Reid, Jenny Powers, Terry Spraker, Ryan J. Monello, Bruce Pulford, Margaret Wild, Michael F. Antolin, Kurt C. Vercauteren, Mark Zabel

United States Department of Agriculture Wildlife Services: Staff Publications

Prions are unique infectious agents that replicate without a genome and cause neurodegenerative diseases that include chronic wasting disease (CWD) of cervids. Immunohistochemistry (IHC) is currently considered the gold standard for diagnosis of a prion infection but may be insensitive to early or sub-clinical CWD that are important to understanding CWD transmission and ecology. We assessed the potential of serial protein misfolding cyclic amplification (sPMCA) to improve detection of CWD prior to the onset of clinical signs. We analyzed tissue samples from free-ranging Rocky Mountain elk (Cervus elaphus nelsoni) and used hierarchical Bayesian analysis to estimate the specificity …

Dynamics Of Virus Shedding And Antibody Responses In Influenza A Virus-Infected Feral Swine, Hailiang Sun, Fred L. Cunningham, Jillian Harris, Yifei Xu, Li-Ping Long, Katie Hanson-Dorr, John A. Baroch, Paul Fioranelli, Mark W. Lutman, Tao Li, Kerri Pedersen, Brandon S. Schmit, Jim Cooley, Xiaoxu Lin, Richard G. Jarman, Thomas J. Deliberto, Xiu-Feng Wan

United States Department of Agriculture Wildlife Services: Staff Publications

Given their free-ranging habits, feral swine could serve as reservoirs or spatially dynamic ‘mixing vessels’ for influenza A virus (IAV). To better understand virus shedding patterns and antibody response dynamics in the context of IAV surveillance amongst feral swine, we used IAV of feral swine origin to perform infection experiments. The virus was highly infectious and transmissible in feral swine, and virus shedding patterns and antibody response dynamics were similar to those in domestic swine. In the virus-inoculated and sentinel groups, virus shedding lasteddays, respectively. Antibody titres in inoculated swine peaked at 1 : 840 on day 11 post-inoculation (p.i.), …

Molecular Characterization Of Salmonella Enterica Isolates Associated With Starling–Livestock Interactions, James C. Carlson, Doreene R. Hyatt, Kevin Bentler, Anna M. Mangan, Michael Russell, Antoinette J. Piaggio, George M. Linz

United States Department of Agriculture Wildlife Services: Staff Publications

Bird–livestock interactions have been implicated as potential sources for bacteria within concentrated animal feeding operations (CAFO). In this study we characterized XbaIdigested genomic DNA from Salmonella enterica using pulsed-field gel electrophoresis (PFGE). The PFGE analysis was conducted using 182 S. enterica isolates collected from a single CAFO between 2009 and 2012. Samples collected in 2012 were subjected to antimicrobial susceptibility testing. The analysis was limited to S. enterica serotypes, with at least 10 isolates, known to occur in both European starlings (Sturnus vulgaris) and cattle (Bos taurus) within this CAFO. A total of five different serotypes were screened; S. Anatum, …

Using The “Placeholder” Concept To Reduce Genetic Introgression Of An Endangered Carnivore, Eric M. Gese, Patricia A. Terletzky

United States Department of Agriculture Wildlife Services: Staff Publications

One of the most endangered species is the redwolf, Canis rufus. Reintroduction of the red wolf began in 1987, but in 1993 hybridization between coyotes (Canis latrans) and wolves was documented. To reduce genetic introgression, coyotes and coyote–wolf hybridswere captured, sterilized, and released as “placeholders”. Placeholders held territories until either displaced or killed by a wolf, or management personnel removed them before releasing a wolf. We evaluated the placeholder concept by examining the number of animals sterilized and released, likelihood of displacement by a wolf, factors influencing displacements, territory fidelity of placeholders, and survival rates and causes of mortality of …

Demographic And Spatiotemporal Patterns Of Avian Influenza Infection At The Continental Scale, And In Relation To Annual Life Cycle Of A Migratory Host, Rodolfo Nallar, Zsuzsanna Papp, Tasha Epp, Frederick A. Leighton, Seth R. Swafford, Thomas J. Deliberto, Robert J. Dusek, Hon S. Ip, Jeffrey Hall, Yohannes Berhane, Samantha E.J. Gibbs, Catherine Soos

United States Department of Agriculture Wildlife Services: Staff Publications

Since the spread of highly pathogenic avian influenza (HPAI) H5N1 in the eastern hemisphere, numerous surveillance programs and studies have been undertaken to detect the occurrence, distribution, or spread of avian influenza viruses (AIV) in wild bird populations worldwide. To identify demographic determinants and spatiotemporal patterns of AIV infection in long distance migratory waterfowl in North America, we fitted generalized linear models with binominal distribution to analyze results from 13,574 blue-winged teal (Anas discors, BWTE) sampled in 2007 to 2010 year round during AIV surveillance programs in Canada and the United States. Our analyses revealed that during late summer staging …

Network Analysis Of Host–Virus Communities In Bats And Rodents Reveals Determinants Of Cross-Species Transmission, Angela D. Luis, Thomas J. O'Shea, David T.S. Hayman, James L.N. Wood, Andrew A. Cunningham, Amy T. Gilbert, James N. Mills, Colleen T. Webb

United States Department of Agriculture Wildlife Services: Staff Publications

Bats are natural reservoirs of several important emerging viruses. Cross-species transmission appears to be quite common among bats, which may contribute to their unique reservoir potential. Therefore, understanding the importance of bats as reservoirs requires examining them in a community context rather than concentrating on individual species. Here, we use a network approach to identify ecological and biological correlates of cross-species virus transmission in bats and rodents, another important host group. We show that given our current knowledge the bat viral sharing network is more connected than the rodent network, suggesting viruses may pass more easily between bat species. We …

Boa Constrictor (Boa Constrictor), Are R. Berentsen, Juan G. Garcia-Cancel, Edna M. Diaz-Negron, Oscar A. Diaz-Marrero, Alberto R. Puente-Rolón, Robert N. Reed, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

USA: PUERTO RICO: MUNICIPALITY OF CABO ROJO: Cabo Rojo National Wildlife Refuge (17.978958°N, 67.170910oW; NAD 83). 10 November 2014. O. A. Diaz-Marrero. Verified by S. M. Boback. National Museum of Natural History, Smithsonian Institution (USNM Herp Image 2838a, b; photo vouchers). First municipality record for this exotic species; all previous reports were restricted to the Municipality of Mayaguez, located ca. 25 km north of Cabo Rojo National Wildlife Refuge. Reynolds et al. (2013. BioI. Invasions 15:953-959) concluded that Boa Constrictor introductions into Puerto Rico were likely related to the pet trade and that they genetically matched snakes belonging to the …

Exploring The Role Of Ospreys In Education, Rebecca Cushing, Brian E. Washburn

United States Department of Agriculture Wildlife Services: Staff Publications

Recent research in childhood education has demonstrated that experiences in nature are important in shaping early environmental consciousness (Hinds and Sparks 2008, Hussar and Horvath 2011, Cheng and Monroe 2012) and ultimately the expression of pro-environmental attitudes and behaviors during adulthood (Wells and Lekies 2006, Chawla and Cushing 2007, Collado et al. 2013). Increasingly, those experiences happen via written and electronic media (e.g., textbooks, computer screens) or in very anthropogenic environments (e.g., in parks and zoos) and less through direct contact with nature, a concept Louv (2005) referred to as ‘‘nature deficit disorder.’’ Even in schools where environmental education is …

Ospreys (Pandion Haliaetus) In The 21st Century: Populations, Migration, Management, And Research Priorities, Richard O. Bierregaard, Alan F. Poole, Brian E. Washburn

United States Department of Agriculture Wildlife Services: Staff Publications

Ospreys (Pandion haliaetus) are remarkable raptors. Their choice of conspicuous nest sites and surprising tolerance for nesting in nearly intimate association with humans render them an iconic piece of aquatic ecosystems in both marine and freshwater habitats across the northern hemisphere and much of Australasia (Australia to Indonesia). Wintering in Central and South America and Africa as well, they are among the few truly cosmopolitan birds of prey. Ecologically, they might be termed generalized specialists. They are, with exceptions so rare that they can safely be ignored, obligate fish eaters. From their talons to the tip of their …

Speed Kills: Ineffective Avian Escape Responses To Oncoming Vehicles, Travis L. Devault, Bradley F. Blackwell, Thomas W. Seamans, Steven L. Lima, Esteban Fernandez-Juricic

United States Department of Agriculture Wildlife Services: Staff Publications

Animal–vehicle collisions cause high levels of vertebrate mortality worldwide, and what goes wrong when animals fail to escape and ultimately collide with vehicles is notwell understood.We investigated alert and escape behaviours of captive brown-headed cowbirds (Molothrus ater) in response to virtual vehicle approaches of different sizes and at speeds ranging from 60 to 360 km h^-1. Alert and flight initiation distances remained similar across vehicle speeds, and accordingly, alert and flight initiation times decreased at higher vehicle speeds. Thus, avoidance behaviours in cowbirds appeared to be based on distance rather than time available for escape, particularly …

White-Tailed Deer Response To Vehicle Approach: Evidence Of Unclear And Present Danger, Bradley F. Blackwelll, Thomas W. Seamans, Travis L. Devault

United States Department of Agriculture Wildlife Services: Staff Publications

The fundamental causes of animal-vehicle collisions are unclear, particularly at the level of animal detection of approaching vehicles and decision-making. Deer-vehicle collisions (DVCs) are especially costly in terms of animal mortality, property damage, and safety. Over one year, we exposed free-ranging white-tailed deer (Odocoileus virginianus) to vehicle approach under low ambient light conditions, from varying start distances, and vehicle speeds from 20 km/h to approximately 90 km/ h. We modeled flight response by deer to an approaching vehicle and tested four hypotheses: 1) flight-initiation distance (FID) would correlate positively with start distance (indicating a spatial margin of safety); …

Does Lethal Control Of Top-Predators Release Mesopredators? A Re-Evaluation Of Three Australian Case Studies, Benjamin L. Allen, Geoff Lundie-Jenkins, Neil D. Burrows, Richard M. Engeman, Peter J.S. Fleming, Luke K.-P. Leung

United States Department of Agriculture Wildlife Services: Staff Publications

Top-predators can sometimes be important for structuring fauna assemblages in terrestrial ecosystems. Through a complex trophic cascade, the lethal control of top-predators has been predicted to elicit positive population responses from mesopredators that may in turn increase predation pressure on prey species of concern. In support of this hypothesis, many relevant research papers, opinion pieces and literature reviews identify three particular case studies as supporting evidence for top-predator controlinduced release of mesopredators in Australia. However, many fundamental details essential for supporting this hypothesis are missing from these case studies, which were each designed to investigate alternative aims. Here, we re-evaluate …

Sympatric Prey Responses To Lethal Top-Predator Control: Predator Manipulation Experiments, Benjamin L. Allen, Lee R. Allen, Richard M. Engeman, Luke K.-P. Leung

United States Department of Agriculture Wildlife Services: Staff Publications

Introduction: Many prey species around the world are suffering declines due to a variety of interacting causes such as land use change, climate change, invasive species and novel disease. Recent studies on the ecological roles of top-predators have suggested that lethal top-predator control by humans (typically undertaken to protect livestock or managed game from predation) is an indirect additional cause of prey declines through trophic cascade effects. Such studies have prompted calls to prohibit lethal top-predator control with the expectation that doing so will result in widespread benefits for biodiversity at all trophic levels. However, applied experiments investigating in situ …

Large-Scale Avian Influenza Surveillance In Wild Birds Throughout The United States, Sarah N. Bevins, Kerri Pedersen, Mark W. Lutman, John A. Baroch, Brandon S. Schmit, Dennis Kohler, Thomas Gidlewski, Dale L. Nolte, Seth R. Swafford, Thomas J. Deliberto

United States Department of Agriculture Wildlife Services: Staff Publications

Avian influenza is a viral disease that primarily infects wild and domestic birds, but it also can be transmitted to a variety of mammals. In 2006, the United States of America Departments of Agriculture and Interior designed a large-scale, interagency surveillance effort that sought to determine if highly pathogenic avian influenza viruses were present in wild bird populations within the United States of America. This program, combined with the Canadian and Mexican surveillance programs, represented the largest, coordinated wildlife disease surveillance program ever implemented. Here we analyze data from 197,885 samples that were collected from over 200 wild bird species. …