Life Sciences Commons^™

Bird Feeders As Locations For Skunk Uptake Of Oral Rabies Vaccine Baits, Tad C. Theimer, Tisheena Talk, Shylo Johnson, David L. Bergman

United States Department of Agriculture Wildlife Services: Staff Publications

Significantly more (54%, P=0.003) placebo baits placed under 26 bird feeders in Arizona, US were removed by striped skunks (Mephitis mephitis) than at paired, nonfeeder locations (19%). Baiting at bird feeders could supplement traditional oral rabies vaccine bait placement in urban-suburban areas while engaging the public in rabies control efforts.

Efficacy Of An Acoustic Hailing Device As An Avian Dispersal Tool, Peter E. Schlichting, Amanda E. Holland, James C. Beasley, Albert L. Bryan, Robert A. Kennamer, Travis L. Devault, Bradley F. Blackwell, Olin E. Rhodes Jr.

United States Department of Agriculture Wildlife Services: Staff Publications

Bird strikes are a major safety and financial concern for modern aviation. Audible stimuli are common bird dispersal techniques, but their effectiveness is limited by the saliency and relevance of the stimulus. Furthermore, high ambient sound levels present at airfields might require that effective audible stimuli rely more on total volume (i.e., exceeding physiological tolerances) than ecological relevance. Acoustic hailing devices (AHD) are capable of sound output with a narrow beamwidth and at volumes high enough to cause physical discomfort at long distances. We tested the effectiveness of anAHD as a dispersal tool on freeranging birds recognized as hazardous to …

Clinostomum Album N. Sp. And Clinostomum Marginatum (Rudolphi, 1819), Parasites Of The Great Egret Ardea Alba L. From Mississippi, Usa, Thomas G. Rosser, Neely R. Alberson, Ethan T. Woodyard, Fred L. Cunningham, Linda M. Pote, Matt J. Griffin

United States Department of Agriculture Wildlife Services: Staff Publications

Members of the genus Clinostomum Leidy, 1856, colloquially known as yellow grubs, are cosmopolitan parasites of piscivorous birds, freshwater snails, fish and amphibians. In the southeastern United States, piscivorous birds present a continuous challenge for producers of farm-raised catfish. Ciconiiform birds are common hosts of Clinostomum spp. in North America and are endemic on most commercial catfish operations. The great egret Ardea albaL. is an avian predator often found foraging on commercial catfish operations, but to date the trematode fauna of great egrets preying on catfish ponds remains mostly understudied. Thirteen great egrets were captured from commercial catfish ponds …

Bayesian Model-Based Age Classification Using Small Mammal Body Mass And Capture Dates, Nathaneal Lichti, Kenneth F. Kellner, Timothy J. Smyser, Scott A. Johnson

United States Department of Agriculture Wildlife Services: Staff Publications

Accurate age determination is a fundamental prerequisite for demographic studies as well as population monitoring efforts that provide information for management and conservation. Yet, common age determination methods suffer from low accuracy rates, impose additional handling and time costs on animals and biologists, or rely on invasive techniques such as tooth extraction. We introduce an alternative, mixture modeling approach for age determination that exploits mammalian growth patterns to classify newly encountered animals as juveniles or adults, and present an example analysis that classifies Allegheny woodrats based solely on their capture dates and mass at capture, in combination with data from …

Development Of Known-Fate Survival Monitoring Techniques For Juvenile Wild Pigs (Sus Scrofa), David A. Keiter, John C. Kilgo, Mark A. Vukovich, Fred L. Cunningham, James C. Beasley

United States Department of Agriculture Wildlife Services: Staff Publications

Context. Wild pigs are an invasive species linked to numerous negative impacts on natural and anthropogenic ecosystems in many regions of the world. Robust estimates of juvenile wild pig survival are needed to improve population dynamics models to facilitate management of this economically and ecologically important invasive species. Despite this critical knowledge gap, to date no successful known-fate study of wild piglet survival (age) has been conducted, due to a lack of appropriate method for this species. Aims. To aid in locating and tagging neonates, we piloted the use of vaginal implant transmitters (VITs) in adult wild pigs and evaluated …

Survival And Habitat Selection Of Canada Geese During Autumn And Winter In Metropolitan Chicago, Usa, Brett E. Dorak, Michael P. Ward, Michael W. Eichholz, Brian E. Washburn, Timothy P. Lyons, Heath M. Hagy

United States Department of Agriculture Wildlife Services: Staff Publications

Winter distribution and resource use of animals is driven by myriad interacting biotic and abiotic factors. Urban areas provide sanctuaries from hunting for game animals and may have thermal benefits during winter through reduced thermoregulatory costs. We deployed cellular GPS transmitters affixed to neck collars of 41 Canada Geese (Branta canadensis) in the Greater Chicago Metropolitan Area (GCMA) of northeastern Illinois, USA, to determine habitat selection and survival during autumn and winter. Canada Geese selected green spaces (59.8%) in greater proportion than available (14%), but they also regularly used industrial urban habitats such as rooftops and rail yards …

Wetland Bird Abundance And Safety Implications For Military Aircraft Operations, Kent Andersson, Craig A. Davis, Bradley F. Blackwell, Jason R. Heinen

United States Department of Agriculture Wildlife Services: Staff Publications

Wetlands with associated avifauna can pose a substantial hazard to aviation safety, potentially increasing bird–aircraft collision (strike) risk when located near air operations areas.We modeled year-round use by wetland avifauna of Drummond Flats Wildlife Management Area (Drummond Flats), a wetland complex located within 10 km of Vance Air Force Base (AFB), Enid, Oklahoma, USA. Our objectives were to 1) quantify seasonal avifauna abundances at Drummond Flats; 2) test a priori models reflecting use by bird species recognized as hazardous to aviation safety relative to environmental factors including flooded wetland habitat and vegetation cover; 3) use these models to predict maximal …

Prevalence Of Feral Swine Disturbance At Important Archaeological Sites Over A Large Landscape In Florida, Richard M. Engeman, Joseph S. Meyer, John B. Allen

United States Department of Agriculture Wildlife Services: Staff Publications

Feral swine are globally known as one of the most destructive invasive vertebrates, damaging native habitats, native plants and animals, agriculture, infrastructure, spreading diseases. There has been little quantification on their disturbance to archaeological sites across a broad landscape. Over 6 years we inspected 293 significant archaeological sites for swine disturbance across a vast area. We found a 42% prevalence of swine disturbance among all sites, with prevalence not distinguishable among prehistoric sites, historic sites, and sites with both components. The areas of disturbance mapped within three historic homestead sites showed 5–26% of total site surface area rooted. Disturbance was …

Novel And Current Rodenticides For Pocket Gopher Thomomys Spp. Management In Vineyards: What Works?, Roger A. Baldwin, Ryan Meinerz, Gary W. Witmer

United States Department of Agriculture Wildlife Services: Staff Publications

BACKGROUND: Rodenticides are often included as part of an integrated pest management approach for managing pocket gophers (Thomomys spp.) given that they are relatively quick and inexpensive to apply. Strychnine has historically been the most effective toxicant for pocket gophers, but its use is currently limited in the United States; alternative registered toxicants have not proven effective. Recent research with baits containing cholecalciferol plus anticoagulant toxicants proved effective against pocket gophers in a lab setting. Therefore, we established a field study to compare cholecalciferol plus anticoagulant combinations [0.03% cholecalciferol plus 0.005% diphacinone (C+D), 0.015% cholecalciferol plus 0.0025% brodifacoum (C+B1), …

Using Species Distribution Models To Define Nesting Habitat Of The Eastern Metapopulation Of Double-Crested Cormorants, Kate L. Sheehan, Samuel T. Esswein, Brian S. Dorr, Greg K. Yarrow, Ron J. Johnson

United States Department of Agriculture Wildlife Services: Staff Publications

When organisms with similar phenotypes have conflicting management and conservation initiatives, approaches are needed to differentiate among subpopulations or discrete groups. For example, the eastern metapopulation of the double-crested cormorant (Phalacrocorax auritus) has a migratory phenotype that is culled because they are viewed as a threat to commercial and natural resources, whereas resident birds are targeted for conservation. Understanding the distinct breeding habitats of resident versus migratory cormorants would aid in identification and management decisions. Here, we use species distribution models (SDM: Maxent) of cormorant nesting habitat to examine the eastern P. auritus metapopulation and the predicted breeding …

Inferring Infection Hazard In Wildlife Populations By Linking Data Across Individual And Population Scales, Kim M. Pepin, Shannon L. Kay, Ben D. Golas, Susan A. Shriner, Amy T. Gilbert, Ryan S. Miller, Andrea L. Graham, Steven Riley, Paul C. Cross, Michael D. Samuel, Mevin B. Hooten, Jennifer A. Hoeting, James O. Lloyd-Smith, Colleen T. Webb, Michael G. Buhnerkempe

United States Department of Agriculture Wildlife Services: Staff Publications

Our ability to infer unobservable disease-dynamic processes such as force of infection (infection hazard for susceptible hosts) has transformed our understanding of disease transmission mechanisms and capacity to predict disease dynamics. Conventional methods for inferring FOI estimate a time-averaged value and are based on population-level processes. Because many pathogens exhibit epidemic cycling and FOI is the result of processes acting across the scales of individuals and populations, a flexible framework that extends to epidemic dynamics and links within-host processes to FOI is needed. Specifically, within-host antibody kinetics in wildlife hosts can be short-lived and produce patterns that are repeatable across …

Field-Based Evaluation Of A Male-Specific (F+) Rna Coliphage Concentration Method, J. C. Chandler, A. Pérez-Méndez, J. Paar Iii, M. M. Doolittle, B. Bisha, L. D. Goodridge

United States Department of Agriculture Wildlife Services: Staff Publications

Fecal contamination of water poses a significant risk to public health due to the potential presence of pathogens, including enteric viruses. Therefore, sensitive, reliable and easy to use methods for the concentration, detection and quantification of microorganisms associated with the safety and quality of water are needed. In this study, we performed a field evaluation of an anion exchange resin-based method to concentrate male-specific (F + ) RNA coliphages (FRNA), fecal indicator organisms, from diverse environmental waters that were suspected to be contaminated with feces. In this system, FRNA coliphages are adsorbed to anion exchange resin and direct nucleic acid …

Advances And Environmental Conditions Of Spring Migration Phenology Of American White Pelicans, D. Tommy King, Guiming Wang, Zhiqiang Yang, Justin W. Fischer

United States Department of Agriculture Wildlife Services: Staff Publications

Spring migration phenology of birds has advanced under warming climate. Migration timing of shortdistance migrants is believed to be responsive to environmental changes primarily under exogenous control. However, understanding the ecological causes of the advancement in avian spring migration phenology is still a challenge due to the lack of long-term precise location data. We used 11 years of Global Positioning System relocation data to determine four different migration dates of the annual migration cycle of the American white pelican (Pelecanus erythrorhynchos), a short-distance migrant. We also tested the hypothesis that increases in winter temperature and precipitation on the …

Field-Based Evaluation Of A Male-Specific (F+) Rna Coliphage Concentration Method, J. C. Chandler, A. Pérez-Méndez, J. Paar Iii, M. M. Doolittle, B. Bisha, L. D. Goodridge

United States Department of Agriculture Wildlife Services: Staff Publications

Fecal contamination of water poses a significant risk to public health due to the potential presence of pathogens, including enteric viruses. Therefore, sensitive, reliable and easy to use methods for the concentration, detection and quantification of microorganisms associated with the safety and quality of water are needed. In this study, we performed a field evaluation of an anion exchange resin-based method to concentrate male-specific (F + ) RNA coliphages (FRNA), fecal indicator organisms, from diverse environmental waters that were suspected to be contaminated with feces. In this system, FRNA coliphages are adsorbed to anion exchange resin and direct nucleic acid …

Comment On: ‘Blood Does Not Buy Goodwill: Allowing Culling Increases Poaching Of A Large Carnivore’, Kim M. Pepin, Shannon L. Kay, Amy J. Davis

United States Department of Agriculture Wildlife Services: Staff Publications

Chapron & Treves [1] present a framework for examining effects of wolf culling policies on wolf population growth rate. They develop a population growth model that estimates an effect of the amount of time per year legal culling is allowed (‘policy effect’) on wolf population growth rates, separate from an effect of culling. They infer that there is substantial evidence for a negative relationship between the proportion of the year that the culling policy is in effect and the population growth rate because 83% of the posterior distribution for the policy effect parameter was negative. They conclude that when it …

Functional Visual Sensitivity To Ultraviolet Wavelengths In The Pileated Woodpecker (Dryocopus Pileatus), And Its Influence On Foraging Substrate Selection, Sean T. O'Daniels, Dylan C. Kesler, Jeanne D. Mihail, Elisabeth B. Webb, Scott J. Werner

United States Department of Agriculture Wildlife Services: Staff Publications

Most diurnal birds are presumed visually sensitive to near ultraviolet (UV)wavelengths, however, controlled behavioral studies investigating UV sensitivity remain few. Although woodpeckers are important as primary cavity excavators and nuisance animals, published work on their visual systems is limited. We developed a novel foraging-based behavioral assay designed to test UV sensitivity in the Pileated Woodpecker (Dryocopus pileatus). We acclimated 21 wild-caught woodpeckers to foraging for frozen mealworms within 1.2 m sections of peeled cedar (Thuja spp.) poles.We then tested the functional significance of UV cues by placing frozen mealworms behind UV-reflective covers, UV-absorptive covers, or decayed red …

Adaptive Use Of Nonlethal Strategies For Minimizing Wolf–Sheep Conflict In Idaho, Suzanne A. Stone, Stewart W. Breck, Jesse Timberlake, Peter M. Haswell, Fernando Najera, Brian S. Bean, Daniel J. Thornhill

United States Department of Agriculture Wildlife Services: Staff Publications

Worldwide, native predators are killed to protect livestock, an action that can undermine wildlife conservation efforts and create conflicts among stakeholders. An ongoing example is occurring in the western United States, where wolves (Canis lupus) were eradicated by the 1930s but are again present in parts of their historic range. While livestock losses to wolves represent a small fraction of overall livestock mortality, the response to these depredations has resulted in widespread conflicts including significant efforts at lethal wolf control to reduce impacts on livestock producers, especially those with large-scale grazing operations on public lands. A variety of …

A Method For The Improved Detection Of Aerosolized Influenza Viruses And The Male-Specific (F+) Rna Coliphage Ms2, J. C. Chandler, J. W. Schaeffer, M. Davidson, S. L. Magzamen, A. Pérez-Méndez, S. J. Reynolds, L. D. Goodridge, J. Volckens, A. B. Franklin, S. A. Shriner, B. Bisha

United States Department of Agriculture Wildlife Services: Staff Publications

The detection of aerosolized viruses can serve as an important surveillance and control tool in agriculture, human health, and environmental settings. Here, we adapted an anion exchange resin-based method, initially developed to concentrate negatively charged viruses from water, to liquid impingement-based bioaerosol sampling. In this method, aerosolized viruses are collected in a 20 ml liquid sample contained within widely used impingers, BioSamplers (SKC Inc., Eighty Four, PA), and further concentrated via adsorption to an anion exchange resin that is suspended within this liquid. Viral nucleic acids are then extracted from the resin to facilitate molecular analyses through a reduction in …

Ecological Potential For Rabies Virus Transmission Via Scavenging Of Dead Bats By Mesocarnivores, Tad C. Theimer, Annie C. Dyer, Brian W. Keeley, Amy T. Gilbert, David L. Bergman

United States Department of Agriculture Wildlife Services: Staff Publications

Multiple species of bats are reservoirs of rabies virus in the Americas and are occasionally the source of spillover infections into mesocarnivore species. Although rabies transmission generally is assumed to occur via bite, laboratory studies have demonstrated the potential for rabies transmission via ingestion of rabid animals. We investigated the ecological potential for this mode of transmission by assessing mesocarnivore scavenging behavior of dead bats in suburban habitats of Flagstaff, Arizona, US. In autumn 2013, summer 2014, and autumn 2015, we placed 104 rabies-negative bat carcasses either near buildings, in wildland areas, or in residential yards and then monitored them …

Addressing The Gender Gap In Distinguished Speakers At Professional Ecology Conferences, Cooper M. Farr, Sara P. Bombaci, Travis Gallo, Anna M. Mangan, Hannah L. Riedl, Lani T. Stinson, Kate Wilkins, Drew E. Bennett, Theresa Nogeire-Mcrae, Liba Pejchar

United States Department of Agriculture Wildlife Services: Staff Publications

Keynote and plenary speakers at professional conferences serve as highly visible role models for early-career scientists and provide recognition of scientific excellence. This recognition may be particularly important for women, who are underrepresented in senior positions in the biological sciences. To evaluate whether conferences fulfill this potential, we examined distinguished speakers at North American ecology conferences between 2000 and 2015 and compared these data with the percentage of women ecologists at diverse career stages. We found that 15%–35% (x = 28%, n = 809) of the distinguished speakers were women, which is significantly lower than the percentage of female ecology …

Fine-Scale Assessment Of Home Ranges And Activity Patterns For Resident Black Vultures (Coragyps Atratus) And Turkey Vultures (Cathartes Aura), Amanda E. Holland, Michael E. Byrne, A. Lawrence Bryan, Travis L. Devault, Olin E. Rhodes Jr., James C. Beasley

United States Department of Agriculture Wildlife Services: Staff Publications

Knowledge of black vulture (Coragyps atratus) and turkey vulture (Cathartes aura) spatial ecology is surprisingly limited despite their vital ecological roles. Fine-scale assessments of space use patterns and resource selection are particularly lacking, although development of tracking technologies has allowed data collection at finer temporal and spatial resolution. Objectives of this study were to conduct the first assessment of monthly home range and core area sizes of resident black and turkey vultures with consideration to sex, as well as elucidate differences in monthly, seasonal, and annual activity patterns based on fine-scale movement data analyses. We collected …

Diversity And Phylogenetic Relationships Among Bartonella Strains From Thai Bats, Clifton D. Mckee, Michael Y. Kosoy, Ying Bai, Lynn M. Osikowicz, Richard Franka, Amy T. Gilbert, Sumalee Boonmar, Charles E. Rupprecht, Leonard Peruski

United States Department of Agriculture Wildlife Services: Staff Publications

Bartonellae are phylogenetically diverse, intracellular bacteria commonly found in mammals. Previous studies have demonstrated that bats have a high prevalence and diversity of Bartonella infections globally. Isolates (n = 42) were obtained from five bat species in four provinces of Thailand and analyzed using sequences of the citrate synthase gene (gltA). Sequences clustered into seven distinct genogroups; four of these genogroups displayed similarity with Bartonella spp. sequences from other bats in Southeast Asia, Africa, and Eastern Europe. Thirty of the isolates representing these seven genogroups were further characterized by sequencing four additional loci (ftsZ, nuoG, rpoB, …

Strength Testing Of Raccoons And Invasive Wild Pigs For A Species-Specific Bait Station, Nathan P. Snow, Michael J. Lavelle, Joseph M. Halseth, Chad R. Blass, Justin A. Foster, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

With the development of a toxic bait (HOGGONE®) for the control of invasive wild pig (IWP; Sus scrofa) populations in the United States, there is a need to develop a bait station to mitigate potential effects on nontarget species. Our objective was to identify characteristics of a bait station that can successfully exclude raccoons (Procyon lotor)—a ubiquitous and dexterous nontarget species—while facilitating bait consumption by IWPs that exhibit group-feeding behaviors. We evaluated abilities of captive raccoons (n = 19) and IWPs (n = 41) to open the lids of prototype resistance assessment bait stations (RABS) …

Comparison Of A Micro-Neutralization Test With The Rapid Fluorescent Focus Inhibition Test For Measuring Rabies Virus Neutralizing Antibodies, Todd G. Smith, Amy T. Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

The rapid fluorescent focus inhibition test (RFFIT) is routinely used in the United States to measure rabies virus neutralizing antibodies (rVNA). RFFIT has a long history of reproducible and reliable results. The test has been modified over the years to use smaller volumes of reagents and samples, but requires a 50 μL minimum volume of test serum. To conduct pathogenesis studies, small laboratory animals such as mice are regularly tested for rVNA, but the minimum volume for a standard RFFIT may be impossible to obtain, particularly in scenarios of repeated sampling. To address this problem, a micro-neutralization test was developed …

Ontogenetic And Ecological Variation In Invasion Risk Of Brown Treesnakes (Boiga Irregularis) On Guam, Shane R. Siers, Julie A. Savidge, Robert N. Reed

United States Department of Agriculture Wildlife Services: Staff Publications

Size structure within populations of invasive species may have consequences for relative risk at all stages of the invasion process, with implications for management interventions such as interdiction, suppression, and eradication. To assess relative distributions of invasive Brown Treesnakes (Boiga irregularis) among demographic categories of management interest, we undertook the most comprehensive and controlled sampling in > 25 years of research into this ecologically and economically destructive introduced predator. We collected a seasonally-balanced sample of 100 snakes from each of 18 sites, stratified by six habitat types, encompassing the species’ entire extralimital range. Samples indicated significant differences in distributions …

The Impact Of Poverty On Dog Ownership And Access To Canine Rabies Vaccination: Results From A Knowledge, Attitudes And Practices Survey, Uganda 2013, Ryan M. Wallace, Jason Mehal, Yoshinori Nakazawa, Sergio Recuenco, Barnabas Bakamutumaho, Modupe Osinubi, Victor Tugumizemu, Jesse D. Blanton, Amy T. Gilbert, Joseph Wamala

United States Department of Agriculture Wildlife Services: Staff Publications

Background: Rabies is a neglected disease despite being responsible for more human deaths than any other zoonosis. A lack of adequate human and dog surveillance, resulting in low prioritization, is often blamed for this paradox. Estimation methods are often employed to describe the rabies burden when surveillance data are not available, however these figures are rarely based on country-specific data.

Methods: In 2013 a knowledge, attitudes, and practices survey was conducted in Uganda to understand dog population, rabies vaccination, and human rabies risk factors and improve in-country and regional rabies burden estimates. Poisson and multi-level logistic regression techniques were conducted …

History Of Regulations, Policy, And Research Related To Conflicts Between Blackbirds And People, George M. Linz, Michael L. Avery, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

The United States and Canada have invested substantial resources over the past 60 years for developing methods to reduce blackbird (Icteridae) damage to agricultural crops, to manage large winter roosts that create nuisance and public health problems, and to mitigate conflicts with endangered species. It is an indication of the challenging nature of the conflicts with these abundant, highly mobile birds that we are still attempting to improve existing methods and develop new approaches to mitigate the problems. Scientists have tested chemical frightening agents and repellents, mechanical scare devices, bird-resistant sunflowers, decoy crops, habitat management, population management, and cultural modifications …

Determination Of 20, 25-Diazacholesterol In Avian Matrices By High Performance Liquid Chromatography/Tandem Mass Spectrometry, Benjamin G. Abbo, Laura E. Hulslander, David A. Goldade

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife contraceptives are an emerging tool for minimizing human-wildlife conflicts. One promising avian contraceptive compound, 20,25-diazacholesterol (DAC), reduces fertility by inhibiting cholesterol synthesis. A reliable analytical method for DAC was required in support of its registration for use as a reproductive control agent in pest bird species. A liquid chromatographic method employing tandem mass spectrometry (LC–MS/MS) was developed for the analysis of tissue extracts following solid phase extraction clean-up. Tissues analyzed were whole body samples from crows, monk parakeets, and quails and liver samples from crows and quails. Excellent sensitivity and selectivity was afforded by tandem mass spectrometry. The method …

Low Viral Doses Are Sufficient To Infect Cottontail Rabbits With Avian Influenza A Virus, J. Jeffrey Root, Susan A. Shriner, Jeremy W. Ellis, Kaci K. Vandalen, Heather J. Sullivan

United States Department of Agriculture Wildlife Services: Staff Publications

Influenza A viruses (IAVs) have been reported in wild lagomorphs in environments where they share resources with waterfowl. Recent studies have conclusively shown that a North American lagomorph, cottontail rabbits (Sylvilagus sp.), become infected following exposure to IAVs and can shed significant quantities of virus. However, the minimum infectious dose and the efficiency of various routes of infection have not been evaluated. Thirty-six cottontail rabbits were used in a dose response study assessing both the oral and nasal routes of infection. The nasal route of infection proved to be the most efficient, as all cottontail rabbits shed viral RNA …

The Economic Impact Of Blackbird Damage To Crops, Stephanie A. Shwiff, Karina L. Ernest, Samantha L. Degroot, Aaron M. Anderson, Steven S. Shwiff

United States Department of Agriculture Wildlife Services: Staff Publications

There are nearly 1,000 species of birds in North America, some of which provide obvious economic benefits like egg production, meat production, bird watching, or hunting (American Bird Association 2016). Some bird species, however, can cause a considerable amount of damage to U.S. agriculture, with estimates of annual damage caused by birds in the United States exceeding US$4.7 billion (Pimentel et al. 2005). Blackbirds (lcteridae) are one group of birds in North America that can cause significant economic damage to commercial grain crops, and to a lesser extent vine and tree crops (Wilson et al. 1989; Dolbeer 1990; Linz et …