Ecology and Evolutionary Biology Commons^™

Biology And Impacts Of Pacific Island Invasive Species. 15. Psittacula Krameri, The Rose-Ringed Parakeet (Psittaciformes: Psittacidae)1, Aaron B. Shiels, Nicholas P. Kalodimos

United States Department of Agriculture Wildlife Services: Staff Publications

The rose-ringed parakeet (RRP), Psittacula krameri, has become established in at least four Pacific Island countries (Hong Kong China, Japan, New Zealand, U.S.A.), including the Hawaiian islands of Kaua‘i, O‘ahu, and Hawai‘i. Most Pacific islands are at risk of RRP colonization. This species was first introduced to Hong Kong in 1903 and Hawai‘i in the 1930s–1960s, established since 1969 in Japan, and in New Zealand since 2005 where it has repeatedly established after organized removals. The founding birds were imported cage-birds from the pet trade. In native India, RRP are generally found associated with human habitation and are considered a …

Using Dna To Identify The Source Of Invasive Mongooses, Herpestes Auropunctatus (Carnivora: Herpestidae) Captured On Kaua‘I, Hawaiian Islands, Darren J. Wostenberg, Matthew W. Hopken, Aaron B. Shiels, Antoinette J. Piaggio

United States Department of Agriculture Wildlife Services: Staff Publications

Two small Indian mongooses (Herpestes auropunctatus) were live-captured in 2012 at separate locations on the Hawaiian Island of Kaua'i, which was previously considered to be free of this invasive species. Genotypes from these two individuals were compared to genotypes of H. auropunctatus from the islands of Hawai'i (n =39), O'ahu (n =91), Maui (n = 39), and Moloka'i (n = 19) to determine the island of origin of the Kaua'i individuals. Genotypes were generated from each individual using five microsatellite loci. Genetic clustering was estimated by Bayesian inference of spatial clustering of individuals and …

Cause‐Specific Mortality Of The World’S Terrestrial Vertebrates, Jacob E. Hill, Travis L. Devault, Jerrold L. Belant

United States Department of Agriculture Wildlife Services: Staff Publications

Aim: Vertebrates are declining worldwide, yet a comprehensive examination of the sources of mortality is lacking. We conducted a global synthesis of terrestrial vertebrate cause‐specific mortality to compare the sources of mortality across taxa and determine predictors of susceptibility to these sources of mortality.

Location: Worldwide.

Time period: 1970–2018.

Major taxa studied: Mammals, birds, reptiles and amphibians.

Methods: We searched for studies that used telemetry to determine the cause of death of terrestrial vertebrates. We determined whether each mortality was caused by anthropogenic or natural sources and further classified mortalities within these two categories (e.g. harvest, vehicle collision and predation). …

In Situ Evaluation Of An Automated Aerial Bait Delivery System For Landscape-Scale Control Of Invasive Brown Treesnakes On Guam, Shane Siers, Will Pitt, John Eisemann, Larry Clark, Aaron B. Shiels, C. S. Clark, R. J. Gosnell, M. C. Messaros

United States Department of Agriculture Wildlife Services: Staff Publications

After decades of biodiversity loss and economic burden caused by the brown treesnake invasion on the Pacific island of Guam, relief hovers on the horizon. Previous work by USDA Wildlife Services (WS) and its National Wildlife Research Center (NWRC) demonstrated that brown treesnake numbers in forested habitats can be dramatically suppressed by aerial delivery of dead newborn mouse (DNM) baits treated with 80 mg of acetaminophen. However, manual bait preparation and application is impractical for landscape-scale treatment. WS, NWRC, and the US Department of the Interior have collaborated with Applied Design Corporation to engineer an automated bait manufacturing and delivery …

Mind The Gap: Experimental Tests To Improve Efficacy Of Fladry For Nonlethal Management Of Coyotes, Julie K. Young, John Draper, Stewart Breck

United States Department of Agriculture Wildlife Services: Staff Publications

Coyotes (Canis latrans) are the top predator of livestock in the contiguous United States. Developing more effective nonlethal tools to prevent coyote depredation will facilitate coexistence between livestock producers and coyotes. Fladry is a nonlethal deterrent designed to defend livestock by creating a visual barrier to wolves (C. lupus). Fladry may also be effective with coyotes, but large gap spacing between flags may reduce its efficacy. To address this issue, we performed 2 experiments on captive coyotes using fladry modified to reduce gap spacing at the U.S. Department of Agriculture, Predator Research Facility in Millville, Utah, USA, during 2015–2016 and …

Persistence And Conspecific Observations Improve Problem-Solving Abilities Of Coyotes, Julie K. Young, Laura Touzot, Stacey P. Brummer

United States Department of Agriculture Wildlife Services: Staff Publications

Social learning has important ecological and evolutionary consequences but the role of certain factors, such as social rank, neophobia (i.e., avoidance of novel stimuli), persistence, and task-reward association, remain less understood. We examined the role of these factors in social learning by captive coyotes (Canis latrans) via three studies. Study 1 involved individual animals and eliminated object neophobia by familiarizing the subjects to the testing apparatus prior to testing. Studies 2 and 3 used mated pairs to assess social rank, and included object neophobia, but differed in that study 3 decoupled the food reward from the testing apparatus (i.e., altered …

Movement Responses Inform Effectiveness And Consequences Of Baiting Wild Pigs For Population Control, Nathan P. Snow, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) damage agricultural and natural resources throughout their nearly global distribution. Subsequently, population control activities (e.g., trapping, shooting, or toxic baiting) frequently involve the deployment of bait to attract wild pigs. A better understanding of how wild pigs respond to bait sites can help maximize efficiency of baiting programs and identify any potential pitfalls. We examined the movement behaviors of 68 wild pigs during three stages of intensive baiting programs (i.e., 15 days each: prior, during, and post baiting) spread across two distinct study areas in southern and northern Texas, USA. We found that bait sites needed …

What Are The Transmission Mechanisms Of Influenza A Viruses In Wild Mammals?, J. Jeffrey Root

United States Department of Agriculture Wildlife Services: Staff Publications

Some influenza A viruses (IAVs) represent serious potential threats to public and agricultural health, with 3 notable examples from the past decade. During 2009, a novel H1N1 IAV (A[H1N1]pdm09), which was first detected in the United States, spread rapidly throughout many regions of the world. In the United States alone, the Centers for Disease Control and Prevention estimated that >60 million human cases were associated with this emergent and pandemic virus. During 2013, a novel H7N9 avian-origin IAV (Asian lineage avian influenza A[H7N9] virus) was first detected in China. This virus not only cost the poultry industry more than $1 …

Raccoon (Procyon Lotor) Response To Ontario Rabies Vaccine Baits (Onrab) In St. Lawrence County, New York, Usa, Kerri Pedersen, Amy T. Gilbert, Kathleen M. Nelson, Daniel P. Morgan, Amy J. Davis, Kurt C. Vercauteren, Dennis Slate, Richard B. Chipman

United States Department of Agriculture Wildlife Services: Staff Publications

Oral rabies vaccination (ORV) campaigns have been conducted annually in the US over the past two decades to prevent raccoon (Procyon lotor) rabies, which is enzootic along the eastern region of the country from southeastern Canada to Alabama. Because raccoon rabies has been eliminated from neighboring Canadian provinces, continued detection of the variant in the US is of concern due to the potential for infected raccoons to cross the border via the St. Lawrence River. Ontario Rabies Vaccine Baits (ONRAB) containing a live, recombinant human adenovirus expressing the rabies virus glycoprotein have been under experimental use in the …

Taking The Bait: Species Taking Oral Rabies Vaccine Baits Intended For Raccoons, Betsy S. Haley, Are R. Berentsen, Richard M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

Raccoon rabies in eastern USA is managed by strategically distributing oral rabies vaccine (ORV) baits. The attractiveness, palativity, density, and non-target species bait take affect ORV effectiveness. We examined raccoon and non-target species differences in investigating/removing fish-meal polymer and coated sachet baits applied to simulate two aerial bait distribution densities. Bait densities of 150 baits/km² and 75 baits/km² were evaluated, respectively, in zones expected to have high and low raccoon densities. Three primary non-target species visited baits: coyotes, white-tailed deer, and feral swine. The proportion of bait stations visited by raccoons during 1 week observation periods ranged from …

Feral Swine Harming Insular Sea Turtle Reproduction: The Origin, Impacts, Behavior And Elimination Of An Invasive Species, Richard M. Engeman, Robert W. Byrd, Jamie Dozier, Mark A. Mcalister, James O. Edens, Elizabeth M. Kierepka, Timothy J. Smyser, Noel Myers

United States Department of Agriculture Wildlife Services: Staff Publications

Feral swine are among the world's most destructive invasive species wherever they are found, with translocations figuring prominently in their range expansions. In contrast, sea turtles are beloved species that are listed as threatened or endangered throughout the world and are the focus of intense conservation efforts. Nest predation by feral swine severely harms sea turtle reproduction in many locations around the world. Here we quantify and economically assess feral swine nest predation at North Island, South Carolina, an important loggerhead sea turtle nesting beach. Feral swine depredation of North Island sea turtle nests was first detected in 2005, with …

Analysis Of Iophenoxic Acid Analogues In Small Indian Mongoose (Herpestes Auropunctatus) Sera For Use As An Oral Rabies Vaccination Biological Marker, Are R. Berentsen, Robert T. Sugihara, Cynthia G. Payne, Israel Leinbach, Steven F. Volker, Ad Vos, Steffen Ortmann, Amy T. Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

The small Indian mongoose (Herpestes auropunctatus) is a reservoir of rabies virus (RABV) in Puerto Rico and comprises over 70% of animal rabies cases reported annually. The control of RABV circulation in wildlife reservoirs is typically accomplished by a strategy of oral rabies vaccination (ORV). Currently no wildlife ORV program exists in Puerto Rico. Research into oral rabies vaccines and various bait types for mongooses has been conducted with promising results. Monitoring the success of ORV relies on estimating bait uptake by target species, which typically involves evaluating a change in RABV neutralizing antibodies (RVNA) post vaccination. This …

Trail Cameras Are A Key Monitoring Tool For Determining Target And Non-Target Bait-Take During Rodent Removal Operations: Evidence From Desecheo Island Rat Eradication, Aaron B. Shiels, D. Will, C. Figuerola-Hernández, K.J. Swinnerton, S. Silander, C. Samra, G.W. Witmer

United States Department of Agriculture Wildlife Services: Staff Publications

Efforts to remove invasive rodents (e.g. Rattus spp. and Mus musculus) from islands often use toxicant-laced baits containing the anticoagulants brodifacoum or diphacinone. Rodenticide baits are generally delivered through aerialor hand-broadcast, or in bait stations. These baits are not rodent-specific and are subject to non-target consumption or secondary exposure (e.g. an individual preying upon another individual that has consumed bait). During rodenticide applications, it is generally unknown which animals are visiting and consuming bait; and to quantify this, we recommend using trail cameras (e.g. Reconyx^tm motion-activated infra-red) positioned to monitor individual bait pellets. To demonstrate the importance and effectiveness …

Experimental Infections Of Norway Rats With Avian‑Derived Low‑Pathogenic Influenza A Viruses, Kaci K. Vandalen, Nicole M. Nemeth, Nicholas O. Thomas, Nicole L. Barrett, Jeremy W. Ellis, Heather J. Sullivan, Alan B. Franklin, Susan A. Shriner

United States Department of Agriculture Wildlife Services: Staff Publications

Influenza A viruses (IAVs) are a public-health, veterinary, and agricultural concern. Although wild birds are considered the primary reservoir hosts for most IAVs, wild-bird IAV strains are known to spill over into poultry, domestic or wild mammals, and humans. Occasionally, spillover events may result in adaptation or reassortment with other strains. Moreover, some IAV strains found in wild waterfowl mutate into highly pathogenic forms in poultry, causing tremendous economic losses. When domestic animals, wildlife, and humans dwell in close proximity to each other, such as may be the case with agricultural operations, wildlife may represent a potential risk for interspecies …

Predation And Disease-Related Economic Impacts Of Wild Pigs On Livestock Producers In 13 States, Aaron M. Anderson, Chris Slootmaker, Erin Harper, Ryan S. Miller, Stephanie A. Shwiff

United States Department of Agriculture Wildlife Services: Staff Publications

We report the results of a survey on wild pigs (Sus scrofa) damage to livestock producers in 13 US states (Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Tennessee, Texas). The survey was distributed by the USDA National Agricultural Statistical Service in the summer of 2017 to a sample of livestock producers in the 13-state region. Findings indicate that predation and disease-related damage can be substantial in certain states and for certain types of livestock. In particular, damage to cattle operations in Texas and Arkansas was substantially higher than damage in other states …

Potential Role Of Wildlife In The Usa In The Event Of A Foot-And-Mouth Disease Virus Incursion, Vienna R. Brown, Sarah N. Bevins

United States Department of Agriculture Wildlife Services: Staff Publications

Foot-and-mouth disease (FMD) is caused by foot-and-mouth disease virus (FMDV) which affects domestic and wild cloven-hoofed species. The FMD-free status of the USA and the tremendous economic impact of a virus incursion motivated the development of this evaluation of the potential role of wildlife in the event of a virus introduction. Additionally, this manuscript contains a summary of US vulnerabilities for viral incursion and persistence which focuses specifically on the possible role of wildlife. The legal movement of susceptible live animals, animal products, by-products and animal feed containing animal products pose a risk of virus introduction and spread. Additionally, the …

Reducing Prairie Dog Populations And Damage By Castration Of Dominant Males, Gary W. Witmer

United States Department of Agriculture Wildlife Services: Staff Publications

Black-tailed prairie dogs (Cynomys ludovicianus) occur widely across the prairie states of North America. They compete with livestock for forage, transmit plague, and damage lawns, landscaping, and property. Interest in non-lethal methods, such as immunocontraception, is growing; however, reductions in the population due to contraception may be offset by increases in survival because adults and yearlings are not subject to the energetic demands of reproduction, and lower densities may increase the amount of resources available to growing offspring. Surgical sterilization provides a means for modeling these effects. Thus, we castrated males prior to the 1998 breeding season to simulate the …

The Role Of Scavenging In Disease Dynamics, Joaquín Vicente, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Contents

Introduction................ 161

The Use of Animal Remains and the Exposure of Scavengers to Disease........ 163

The Relevance of Scavenging for Pathogens to Spread and Persist.......... 166

Human Related Factors Resulting in Increased Risk for Disease Transmission Through Scavenging.............. 170

Management of Scavenging to Reduce Disease Risks.............. 173

Restoration of Large Predators.................. 174

Elimination of Hunting of Scavengers............ 174

Destruction of Big Game and Domestic Animal Carcasses........... 174

Restoration of the Effects of Overabundance............. 175

Excluding Mammalian and Avian Scavengers from Natural Carrions.......... 176

Excluding Mammalian and Avian Scavengers from Vulture Restaurants........... 176

Conclusions and Future Perspectives........... 178

References............... 178

Safety, Stephen M. Vantassel, Brenda K. Osthus

Wildlife Damage Management Technical Series

Wildlife damage management (WDM) is an exciting field with many opportunities to provide solutions to the complex issues involved in human-wildlife interactions. In addition, WDM wildlife control operators (WCO) face a variety of threats to their physical well-being. Injuries can result from misused (Figure 1), faulty, or poorly maintained equipment, inexperience, mishandled wildlife, harsh weather, and dangerous situations, such as electrical lines. The goals of this publication are to: * Develop an awareness of safety issues and adopt a mindset of “Safety First”, * Review the major safety threats that WCOs face, * Provide basic information for WCOs to protect …

Behavioral Insights Into Nociceptor Function: A Systematic Approach To Understanding Postsurgical And Neuropathic Pain Mechanisms In Rats, Max Odem

Dissertations and Theses (Open Access)

Postsurgical and neuropathic pain are each clinically common, and often associated with ongoing pain. Ongoing pain has been linked to ongoing activity (OA) in human C-fiber nociceptors. Preclinical studies using rodent neuropathic models have concentrated on allodynia driven by OA generated in non-nociceptive Aβ fibers, but little attention has been paid to postsurgical pain in sham controls or to C-fiber nociceptor OA promoting ongoing pain.

Operant assays that reveal negative motivational and cognitive aspects of voluntary pain-related behavior may be particularly sensitive to pain-related alterations. In the mechanical conflict (MC) test, rodents can freely choose to escape from a brightly …

Effect Of Macrograzers (Campostoma Spp. And Faxonius Spp.) On Periphyton In Ozark Streams With Considerations Given To Macrograzer Biomass, Phosphorus, And Season: Mensurative And Manipulative Studies, Kayla R. Sayre

Graduate Theses and Dissertations

Nutrient and benthic algal biomass relationships can guide numeric nutrient criteria development in lotic systems. However, herbivorous macrograzers may confound this relationship by reducing the slope of the positive relationship between nutrients and periphyton biomass in streams. I conducted a mensurative field study to determine if stoneroller and crayfish abundance related to algal biomass at varying nutrient concentrations and manipulated macrograzer presence with electrical exclosures in streams to examine macrograzer effects on algal biomass and understand whether these effects on periphyton varied with total phosphorus (TP) or season. Macrograzer density was quantified across a TP gradient (n=15 streams; range = …

No Evidence For Kin Protection In The Expression Of Sickness Behaviors In House Mice, Patricia C. Lopes, Per Block, Alice Pontiggia, Anna K. Lindholm, Barbara König

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

When infected, animals change their behaviors in several ways, including by decreasing their activity, their food and water intake, and their interest in social interactions. These behavioral alterations are collectively called sickness behaviors and, for several decades, the main hypotheses put forward to explain this phenomenon were that engaging in sickness behaviors facilitated the fever response and improved the likelihood of host survival. However, a new hypothesis was recently proposed suggesting that engaging in sickness behaviors may serve to protect kin. We tested this kin protection hypothesis by combining a field and a laboratory experiment in house mice. In both …

The Phylogenetic Signal In Tooth Wear: What Does It Mean?, Larisa Desantis, Mikael Fortelius, Frederick E Grine, Christine Janis, Thomas M Kaiser, Gildas Merceron, Mark A Purnell, Ellen Schulz-Kornas, Juha Saarinen, Mark F. Teaford, Peter S Ungar, Indrė Žliobaitė

Faculty Publications & Research of the TUC College of Osteopathic Medicine

A new study by Fraser et al (2018) urges the use of phylogenetic comparative methods, whenever possible, in analyses of mammalian tooth wear. We are concerned about this for two reasons. First, this recommendation may mislead the research community into thinking that phylogenetic signal is an artifact of some sort rather than a fundamental outcome of the evolutionary process. Secondly, this recommendation may set a precedent for editors and reviewers to enforce phylogenetic adjustment where it may unnecessarily weaken or even directionally alter the results, shifting the emphasis of analysis from common patterns manifested by large clades to rare cases.

Hidden Cost Of Disease In A Free-Ranging Ungulate: Brucellosis Reduces Mid-Winter Pregnancy In Elk, Gavin C. Cotterill, Paul C. Cross, Arthur D. Middleton, Jared D. Rogerson, Brandon M. Scurlock, Johan T. Du Toit

Wildland Resources Faculty Publications

Demonstrating disease impacts on the vital rates of free‐ranging mammalian hosts typically requires intensive, long‐term study. Evidence for chronic pathogens affecting reproduction but not survival is rare, but has the potential for wide‐ranging effects. Accurately quantifying disease‐associated reductions in fecundity is important for advancing theory, generating accurate predictive models, and achieving effective management. We investigated the impacts of brucellosis (Brucella abortus) on elk (Cervus canadensis) productivity using serological data from over 6,000 captures since 1990 in the Greater Yellowstone Ecosystem, USA. Over 1,000 of these records included known age and pregnancy status. Using Bayesian multilevel models, …

Checklist Of Bloodfeeding Mites (Acari: Spinturnicidae) From The Wings Of Bats (Mammalia: Chiroptera) In The Manú Biosphere Reserve, Peru, Donald Gettinger

MANTER: Journal of Parasite Biodiversity

A survey collection of mites of the family Spinturnicidae from Peruvian bats includes 11 species of Periglischrus (acutisternus, gameroi, grandisoma, herrerai, hopkinsi, iheringi, micronycteridis, ojasti, paracutisternus, paravargasi, and ramirezi) and 2 Spinturnix (americanus and bakeri); almost all represent new locality records. This survey collection is available for further study at the following repositories: The Harold W. Manter Laboratory of Parasitology, University of Nebraska–Lincoln; the Field Museum of Natural History, Chicago; and the Laboratório de Espeleobiologia y Acarologia, Universidad Nacional Autónoma de México. When spinturnicid mites are …

Justice Served Fresh: Associations Between Food Insecurity, Community Gardening, And Property Value, Micajah Daniels, Courtney Coughenour Ph.D

McNair Poster Presentations

Numerous stakeholders in Nevada have used a variety of efforts to combat the growth of food insecurity facing Nevadans. The purpose of this research project is to understand the association between food insecurity, community gardens, and property value. Following the wealth of scholarship on these topics and data collected from community garden agencies in Southern Nevada, the research questions for this project include: (1) Where are community gardens located in SNV? (2) What efforts community gardens agencies are doing to address food insecurity (most interested in their efforts using community gardens)? (3) What are the perceptions of supports and barriers …

Horse Y Chromosome Assembly Displays Unique Evolutionary Features And Putative Stallion Fertility Genes, Jan E. Janečka, Brian W. Davis, Sharmila Ghosh, Nandina Paria, Pranab J. Das, Ludovic Orlando, Mikkel Schubert, Martin K. Nielsen, Tom A. E. Stout, Wesley Brashear, Gang Li, Charles D. Johnson, Richard P. Metz, Al Muatasim Al Zadjali, Charles C. Love, Dickson D. Varner, Daniel W. Bellott, William J. Murphy, Bhanu P. Chowdhary, Terje Raudsepp

Veterinary Science Faculty Publications

Dynamic evolutionary processes and complex structure make the Y chromosome among the most diverse and least understood regions in mammalian genomes. Here, we present an annotated assembly of the male specific region of the horse Y chromosome (eMSY), representing the first comprehensive Y assembly in odd-toed ungulates. The eMSY comprises single-copy, equine specific multi-copy, PAR transposed, and novel ampliconic sequence classes. The eMSY gene density approaches that of autosomes with the highest number of retained X–Y gametologs recorded in eutherians, in addition to novel Y-born and transposed genes. Horse, donkey and mule testis RNAseq reveals several candidate genes for stallion …

Transcriptomics Of Learning, Pablo Iturralde

Theses

Learning is a basic and important component of behavior yet we have very little empirical information about the interaction between mechanisms of learning and evolution. In our work, we are testing hypotheses about the neurogenetic mechanisms through which animal learning abilities evolve. We are able to test this directly by using experimentally evolved populations of flies, which differ in learning ability. These populations were previously evolved within the lab by creating worlds with different patterns of change following theoretically predicted effects on which enhanced learning will evolve. How has evolution acted to modulate genes and gene expression in the brain …

Pollen Evidence Of Medicine From An Embalming Jar Associated With Vittoria Della Rovere, Florence, Italy, Karl Reinhard, Kelsey B. Lynch, Annie Larsen, Braymond Adams, Leon Higley, Marina Milanello Do Amaral, Julia Russ, Donatella Lippi, Johnica J. Morrow, Dario Piombino-Mascali

Karl Reinhard Publications

Various samples of human viscera fragments, sponges, and cloth were collected from embalming jars belonging to members of the Medici family of Florence. One jar was labeled with the name Vittoria della Rovere, who died in March of 1694. This jar contained viscera fragments that were identified as a section of collapsed intestine. The intestine of the Vittoria della Rovere sample contained a large concentration of pollen belonging to the Myrtaceae family. The Myrtaceae pollen was sometimes observed in clusters during analysis, which is indicative of purposeful ingestion of flowers, buds, or a substance derived from floral structures. Thus, the …

Ethical Foundations For The Lethal Management Of Double-Crested Cormorants (Phalocrocorax Auritus) In The Eastern United States: An Argument Analysis, Chelsea Batavia, Michael Paul Nelson

Ethics and Conservation Biology Collection

Lethal management of Double-crested Cormorants (Phalocrocorax auritus) has been implemented in many areas of the United States. In this paper, the philosophical method of argument analysis is used to assess ethical premises underlying the proposition that Double-crested Cormorant populations should be culled to reduce pressures on wild fisheries in the Great Lakes region of the eastern USA. This influential argument has been used to justify the destruction of more than half a million Double-crested Cormorants and hundreds of thousands of their nests and eggs. Three versions of the argument are formulated and assessed. It is shown that each of the …