Digital Commons Network^™

Avian Influenza A Viruses Reassort And Diversify Differently In Mallards And Mammals, Ketaki Ganti, Anish Bagga, Juliana Dasilva, Samuel S. Shepard, John R. Barnes, Susan A. Shriner, Katia Koelle, Anice C. Lowen

United States Department of Agriculture Wildlife Services: Staff Publications

Reassortment among co-infecting influenza A viruses (IAVs) is an important source of viral diversity and can facilitate expansion into novel host species. Indeed, reassortment played a key role in the evolution of the last three pandemic IAVs. Observed patterns of reassortment within a coinfected host are likely to be shaped by several factors, including viral load, the extent of viral mixing within the host and the stringency of selection. These factors in turn are expected to vary among the diverse host species that IAV infects. To investigate host differences in IAV reassortment, here we examined reassortment of two distinct avian …

Impacts Of A Large Invasive Mammal On Water Quality In Riparian Ecosystems, Sara Bolds, B. Graeme Lockaby, Stephen S. Ditchkoff, Mark D. Smith, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) are a highly invasive species in many regions of the world and can act as ecosystem engineers in areas where they are established. In riparian ecosystems, wild pigs may affect water quality parameters and introduce fecal bacteria, although previous studies have reported conflicting results. We propose four conditions that we believe are needed for an accurate assessment of wild pig impacts on water quality and address each one in our study. Water samples were collected between May 2018 and June 2019 in riparian watersheds on a privately owned property in Alabama that was densely populated by …

European Starling Nest‐Site Selection Given Enhanced Direct Nest Predation Risk, Bradley Blackwell, Thomas W. Seamans, Morgan Pfeiffer, Bruce N. Buckingham

United States Department of Agriculture Wildlife Services: Staff Publications

The European starling (Sturnus vulgaris) is recognized, outside its native range, as an invasive species, and efforts to deter its nesting have generally been unsuccessful. Enhancing perceived risk at the nest site is a little‐explored route in developing a nest deterrent. Specifically, nest predation risk affects site selection, reproduction, antipredator behavior, and fitness in nesting birds. We questioned whether perceived predation risk as related to a snake model positioned inside a nest box, in striking form, moving, and present throughout the period of cavity site selection would induce European starlings to avoid or delay nest construction. We conducted our study …

Modelling The Factors Affecting The Probability For Local Rabies Elimination By Strategic Control, Johann L. Kotzé, John Duncan Grewar, Aaron M. Anderson

United States Department of Agriculture Wildlife Services: Staff Publications

Dog rabies has been recognized from ancient times and remains widespread across the developing world with an estimated 59,000 people dying annually from the disease. In 2011 a tri-partite alliance consisting of the OIE, the WHO and the FAO committed to globally eliminating dog-mediated human rabies by 2030. Regardless of global support, the responsibility remains with local program managers to implement successful elimination programs. It is well known that vaccination programs have a high probability of successful elimination if they achieve a population-coverage of 70%. It is often quoted that reducing population turnover (typically through sterilizations) raises the probability for …

Efficacy And Risks From A Modified Sodium Nitrite Toxic Bait For Wild Pigs, Nathan P. Snow, Jason Wishart, Justin A. Foster, Linton D. Staples, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

BACKGROUND: Wild pigs (Sus scrofa) are a destructive invasive species throughout many regions of the world. In 2018, a field evaluation of an early prototype of a sodium nitrite (SN) toxic bait in the United States revealed wild pigs dropped large amounts of the toxic bait outside the pig-specific bait stations while feeding, and thus subsequent hazards for non-target animals. We modified the SN-toxic bait formulation, the design of the bait station, and the baiting strategy to reduce dropped bait. We tested the modifications in Queensland, Australia (December 2018), Alabama, USA (August 2019), and Texas, USA (March 2020) …

Daily And Landscape Influences Of Species Visitation To Toxic Bait Sites For Wild Pigs, Nathan P. Snow, Joseph M. Halseth, Michael P. Glow, Michael Lavelle, Justin Fischer, Eric H. Vannatta, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Toxic baiting of wild pigs (Sus scrofa) is a potential new tool for population control and damage reduction in the United States. Use of toxic bait sites by non‐target species is concerning because of the risks posed from exposure to a toxic bait. A 2018 field trial in northern Texas, USA, examining the efficacy of a prototype toxic bait (HOGGONE®, containing 10% sodium nitrite) revealed unexpected hazards to non‐target species, primarily passerine birds, from consuming toxic bait spilled outside of bait stations by wild pigs. The hazards jeopardize the ability to register HOGGONE as a tool for controlling …

Effects Of Social Structure And Management On Risk Of Disease Establishment In Wild Pigs, Anni Yang, Peter E. Schlichting, Bethany Wight, Wesley M. Anderson, Sarah M. Chinn, Mark Q. Wilber, Ryan S. Miller, James C. Beasley, Raoul Boughton, Kurt C. Vercauteren, George Wittemyer, Kim M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

1. Contact heterogeneity among hosts determines invasion and spreading dynamics of infectious disease, thus its characterization is essential for identifying effective disease control strategies. Yet, little is known about the factors shaping contact networks in many wildlife species and how wildlife management actions might affect contact networks.

2. Wild pigs in North America are an invasive, socially structured species that pose a health concern for domestic swine given their ability to transmit numerous devastating diseases such as African swine fever (ASF). Using proximity loggers and GPS data from 48 wild pigs in Florida and South Carolina, USA, we employed a …

Invasive Species In Puerto Rico: The View From El Yunque, Jess Zimmerman, Julissa Rojas-Sandoval, Aaron B. Shiels

United States Department of Agriculture Wildlife Services: Staff Publications

Native flora and fauna of Puerto Rico have a long biogeographic connection to South America. Theory and empirical evidence suggest that islands, particularly those distantly isolated from the mainland, should be more susceptible to naturalizations and invasions of non-native species than continental areas. Anthropogenic disturbances can facilitate accidental and deliberate introductions of non-native species. In this study, we asked: What is the current status of introduced species within El Yunque National Forest (EYNF), the largest and most well-conserved forest area of Puerto Rico? To address this question, we reviewed the literature and surveyed local experts to identify introduced plant and …

Evaluating Lethal Toxicant Doses For The Largest Individuals Of An Invasive Vertebrate Predator With Indeterminate Growth, Shane R. Siers, Scott M. Goetz, Rachel M. Volsteadt, Melia G. Nafus

United States Department of Agriculture Wildlife Services: Staff Publications

The brown treesnake (Boiga irregularis) was accidentally introduced to Guam and caused severe ecological and economic damages. Acetaminophen is an effective, low-risk oral toxicant for invasive brown treesnakes, and an automated aerial delivery system (ADS) has been developed for landscape-scale toxic bait distribution. A fixed dose of 80 mg of acetaminophen within a tablet inserted into a dead neonatal mouse (DNM) was lethal for all brown treesnakes in previous trials; however, these trials did not include very large individuals which are difficult to acquire for testing. Because most reptiles continue to grow throughout their lifespan, a small number …

A Sonic Net Reduces Damage To Sunflower By Blackbirds (Icteridae): Implications For Broad-Scale Agriculture And Crop Establishment, Amanda K. Werrell, Page E. Klug, Romuald N. Lipcius, John P. Swaddle

United States Department of Agriculture Wildlife Services: Staff Publications

Blackbirds, such as red-winged blackbirds (Agelaius phoeniceus), are notorious agricultural pests and damage crops at multiple stages of growth. Our aim was to test a novel deterrent, the use of sound designed to mask communication among birds (termed a “Sonic Net”), to deter blackbirds (Icteridae) from target areas of maturing sunflower crops. The Sonic Net masks communication of a target species by delivering “pink noise” that overlaps with the frequencies that the species uses for acoustic communication. If birds cannot hear predators or conspecific warning calls their perceived predation risk increases, and they relocate to an area with …

Distribution And Abundance Of Scaup Using Baitfish And Sportfish Farms In Eastern Arkansas, Stephen A. Clements, Brian S. Dorr, Brian Davis, Luke A. Roy, Carole R. Engle, Katie C. Hanson-Dorr, Anita M. Kelly

United States Department of Agriculture Wildlife Services: Staff Publications

Arkansas' bait- and sportfish facilities are commonly used by various piscivorous bird species, including lesser scaup (Aythya affinis) and greater scaup (A. marila) that consume substantial quantities of fish. To mediate this predation, farmers implement extensive bird harassment programs that create additional costs to fish loss, thus research investigating the distribution and abundance of scaup is needed to help farmers allocate their bird harassment efforts more efficiently. In winters 2016–2017 and 2017–2018 we conducted 1,368 pond surveys to investigate pond use by scaup on farms during birds' regular wintering period (i.e., November–March). We used intrinsic and …

Economic Effects Of Predation By Scaup On Baitfish And Sportfish Farms, Carole R. Engle, Stephen Clements, Brian S. Dorr, J. Brian Davis, Luke A. Roy, Anita M. Kelly

United States Department of Agriculture Wildlife Services: Staff Publications

Fish-eating birds have been found to consume baitfish and sportfish raised on farms in the United States. Understanding the on-farm economic effects of such wildlife conflicts is essential for wildlife management agencies to make informed decisions. Lesser scaup, while not widely considered a fisheating bird, will consume farmed fish. Baitfish and sportfish farms in Arkansas (the major baitfish and sportfish producingstate in the U.S.) were surveyed to gather data on the cost of protecting farm crops from scaup. The values of lost sales revenue from the various species of baitfish and sportfish consumed by scaup were estimated based on a …

Avian Influenza A Viruses Reassort And Diversify Differently In Mallards And Mammals, Ketaki Ganti, Anish Bagga, Juliana Dasilva, Samuel S. Shepard, John R. Barnes, Susan A. Shriner, Katia Koelle, Anice C. Lowen

United States Department of Agriculture Wildlife Services: Staff Publications

Reassortment among co-infecting influenza A viruses (IAVs) is an important source of viral diversity and can facilitate expansion into novel host species. Indeed, reassortment played a key role in the evolution of the last three pandemic IAVs. Observed patterns of reassortment within a coinfected host are likely to be shaped by several factors, including viral load, the extent of viral mixing within the host and the stringency of selection. These factors in turn are expected to vary among the diverse host species that IAV infects. To investigate host differences in IAV reassortment, here we examined reassortment of two distinct avian …

Landscape Use By Fishers (Pekania Pennanti): Core Areas Differ In Habitat Than The Entire Home Range, Jennifer R. Kordosky, Eric M. Gese, Craig M. Thompson, Patricia A. Terletzky, Kathryn L. Purcell, Jon D. Schneiderman

United States Department of Agriculture Wildlife Services: Staff Publications

Home ranges have long been studied in animal ecology. Core areas may be used at a greater proportion than the rest of the home range, implying the core contains dependable resources. The Pacific fisher (Pekania pennanti (Erxleben, 1777)) is a rare mesocarnivore occupying a small area in the Sierra Nevada Mountains, California, USA. Once statewide, fishers declined in the 1900s due to trapping, habitat fragmentation, and development. Recently, drought induced by climate change may be affecting this population. We examined space use of fishers in their core versus their home range for levels of anthropogenic modifications (housing density, road density, …

Improved Strategies For Handling Entire Sounders Of Wild Pigs, Michael Lavelle, Nathan P. Snow, Christine K. Ellis, Joe M. Halseth, Justin W. Fischer, Michael P. Glow, Eric H. Vannatta, Bethany A. Friesenhahn, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

As wild pigs (Sus scrofa) expand throughout North America researchers are increasingly being tasked with trapping and marking entire sounders (family groups) to attach monitoring devices or other identifying markers to gather knowledge to inform management. Capture and marking procedures can be challenging, dangerous for both researchers and animals, and time consuming, particularly when handling sounders. We developed an integrated pig‐handling system to efficiently sort, weigh, chemically immobilize, and mark multiple wild pigs simultaneously in a controlled manner. To assess the functionality of the system, we evaluated 18 capture events in Texas, USA, from January 2018 to March …

Measuring Adrenal And Reproductive Hormones In Hair From Southern Beaufort Sea Polar Bears (Ursus Maritimus), Marilize Van Der Walt, Lorin A. Neuman-Lee, Patricia A. Terletzky, Todd C. Atwood, Eric M. Gese, Susannah S. French

United States Department of Agriculture Wildlife Services: Staff Publications

Polar bears (Ursus maritimus) use sea ice to access marine mammal prey. In Alaska’s Southern Beaufort Sea, the declining availability of sea ice habitat in summer and fall has reduced opportunities for polar bears to routinely hunt on the ice for seals, their primary prey. This reduced access to prey may result in physiological stress with subsequent potential consequences to reproductive function (physiological changes that accompany reproduction), which can be measured via reproductive hormones. Hormone concentrations in hair can be used as a minimally invasive alternative to serum concentrations, which must come from animal captures. Hair samples also …

Toxoplasma Gondii Prevalence In Carnivorous Wild Birds In The Eastern United States, Sawsan Ammar, Liberty Wood, Chunlei Su, Maria Spriggs, Justin Brown, Kyle Van Why, Richard Gerhold

United States Department of Agriculture Wildlife Services: Staff Publications

Toxoplasma gondii is an important zoonotic protozoan parasite that can infect all warm-blooded animals including mammals and birds. Raptors can be intermediate hosts for T. gondii and the infection may be dependent on their feeding habits. In this study, we investigated the seroprevalence of T. gondii in ten raptor species from Florida, Pennsylvania, and Tennessee followed by a parasite bioassay on select seropositive samples. From a total of 155 raptors, we detected T. gondii antibodies using a modified agglutination test (cutoff 1:25) in 32 (20.6%) birds. The T. gondii seroprevalence was 44.8% in Falconiformes (13/29), 75% in Strigiformes (15/20), and …

Evaluation Of A Warfarin Bait For Controlling Invasive Wild Pigs (Sus Scrofa), James C. Beasley, Lindsay M. Clontz, Allison Rakowski, Nathan P. Snow, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

BACKGROUND: Wild pigs (Sus scrofa) cause widespread environmental and economic damage, and as a result are subjected to extensive control. Current management strategies have proven insufficient, and there is growing interest in use of toxicants to control invasive populations of this species. In 2017 a low-dose warfarin bait was federally approved for use in controlling wild pigs in the United States. However, no states have allowed use of this bait due to unanswered questions regarding welfare concerns, field efficacy, and non-target impacts.

RESULTS: All captive wild pigs fed 0.005% warfarin baits in no choice feeding trials succumbed in an average …

Oral Rabies Vaccination Of Small Indian Mongooses (Urva Auropunctata) With Onrab Via Ultralite Baits, Are R. Berentsen, Israel Leinbach, Mel J. Rivera-Rodriguez, Amy T. Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

The Ontario Rabies Vaccine (ONRAB) is a human adenovirus rabies glycoprotein recombinant oral vaccine immunogenic for small Indian mongooses when delivered by direct instillation into the oral cavity. We offered Ultralite baits containing ~1.8 mL 109.5 TCID50 ONRAB oral rabies vaccine to 18 mongooses, while 6 mongooses were offered identical baits in placebo form. We collected sera from individual mongooses at days 0, 14 and 30 post vaccination (pv) and quantified rabies virus neutralizing antibodies (RVNA) using the rapid fluorescent focus inhibition test, with titers greater than or equal to 0.1 IU/mL considered positive. All study subjects were RVNA negative …

Biodetection Of A Specific Odor Signature In Mallard Feces Associated With Infection By Low Pathogenic Avian Influenza A Virus, Glen J. Golden, Meredith Jj. Grady, Hailey E. Mclean, Susan A. Shriner, Airn E. Hartwig, Richard A. Bowen, Bruce A. Kimball

United States Department of Agriculture Wildlife Services: Staff Publications

Outbreaks of avian influenza virus (AIV) infection included the spread of highly pathogenic AIV in commercial poultry and backyard flocks in the spring of 2015. This resulted in estimated losses of more than $8.5 million from federal government expenditures, $1.6 billion from direct losses to produces arising from destroyed turkey and chicken egg production, and economy-wide indirect costs of $3.3 billion from impacts on retailers and the food service industries. Additionally, these outbreaks resulted in the death or depopulation of nearly 50 million domestic birds. Domesticated male ferrets (Mustela putorius furo) were trained to display a specific conditioned behavior (i.e. …

Surgical Sterilization Impacts On Behavior Of Coyote Pairs, Tyler Leary, Jeffrey T. Schultz, Julie K. Young

United States Department of Agriculture Wildlife Services: Staff Publications

Coyotes (Canis latrans) involved in depredation of livestock, an act frequently resulting in human-wildlife conflict, often do so out of necessity for provisioning pups. Surgical sterilization methods such as vasectomy that preserve gonadal hormones have been successful in reducing depredation by free-ranging coyotes while allowing individuals to maintain territoriality and mate fidelity. However, use of these methods remain costly and ineffective for wide-scale use. Given the alternative proposal of using chemical sterilization techniques, we investigated whether the use of hormone-altering sterilization methods impacted behavior of captive coyote pairs (i.e., male-female pair bonds). Our objective was to evaluate behavior …

Systematic And Other Reviews: Criteria And Complexities, Robert T. Sataloff, Matthew L. Bush, Rakesh Chandra, Douglas Chepeha, Brian Rotenberg, Edward W. Fisher, David Goldenberg, Ehab Y. Hanna, Joseph E. Kerschner, John H. Krouse

School of Medicine Publications

Review articles can be extremely valuable. They synthesize information for readers, often provide clarity and valuable insights into a topic; and good review articles tend to be cited frequently. Review articles do not require Institutional Review Board (IRB) approval if the data reviewed are public (including private and government databases) and if the articles reviewed have received IRB approval previously. However, some institutions require IRB review and exemption for review articles. So, authors should be familiar with their institution's policy. In assessing and interpreting review articles, it is important to understand the article's methodology, scholarly purpose and credibility. Many readers, …

Social Identity And Acceptability Of Wild Pig (Sus Scrofa) Control Actions: A Case Study Of Texas Hunters, Lauren Jaebker, Tara L. Teel, Alan D. Bright, Hailey E. Mclean, John M. Tomeček, Maureen G. Frank, Rachael L. Connally, Stephanie A. Shwiff, Keith M. Carlisle

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) pose significant challenges to wildlife managers. This research explored Texas hunters’ acceptability of wild pig control actions, and whether acceptability varied according to hunters’ affiliation with four different categories of natural resource organizations as an indicator of social identity. Results of a survey (n = 37,317) revealed that most hunters were accepting of all control actions except toxicants and non-lethal deterrents. Mean acceptability scores for each action differed significantly across the four affiliation categories, but effect sizes were minimal. Hunters affiliated with agricultural organizations were the most accepting of control actions, while hunters with …

Social Media As A Window Into Human-Wildlife Interactions And Zoonotic Disease Risk: An Examination Of Wild Pig Hunting Videos On Youtube, Hailey E. Mclean, Lauren M. Jaebker, Aaron M. Anderson, Tara L. Teel, Alan D. Bright, Stephanie A. Shwiff, Keith M. Carlisle

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) damage agriculture and the environment, as well as transmit diseases to animals and people. Hunters are particularly vulnerable to zoonotic disease risks when harvesting wild pigs. Management agencies have endeavored to inform the public about disease risks associated with wild pigs and best practices for mitigating such risks. However, the extent that this guidance has reached hunters and influenced their practices is unclear. We approached this topic through an analysis of wild pig hunting videos on YouTube. We found evidence of relatively few behaviors and communications regarding disease risks and best practices for personal …

Relative Acceptance Of Brodifacoum Pellets And Soft Bait Sachets By Polynesian Rats (Rattus Exulans) On Wake Atoll, Peter J. Kappes, Shane R. Siers

United States Department of Agriculture Wildlife Services: Staff Publications

Removing invasive rats from island ecosystems using rodenticides has proven conservation benefits and is an important management tool for conserving and restoring island ecosystems. However, rodenticide-based eradications can fail if not all rats consume enough bait to result in lethal toxicosis. A recent post-operational review of a failed attempt to eradicate rats from Wake Atoll suggested that some individuals may not have ingested a lethal dose of rodenticide due to potential dietary and/or sensory preferences developed via regular access to anthropogenic food sources. These food sources may be higher in fats and oils, possessing different sensory properties (e.g., softer, chewier, …

Influenza A Virus Surveillance, Infection And Antibody Persistence In Snow Geese (Anser Caerulescens), Susan A. Shriner, J. Jeffrey Root, Jeremy W. Ellis, Kevin T. Bentler, Kaci K. Vandalen, Thomas Gidlewski, Sarah N. Bevins

United States Department of Agriculture Wildlife Services: Staff Publications

Some snow geese (Anser caerulescens) migrate between Eurasia and North America and exhibit high seroprevalence for influenza A viruses (IAVs). Hence, these birds might be expected to play a role in intercontinental dispersal of IAVs. Our objective in this manuscript was to characterize basic incidence and infection characteristics for snow geese to assess whether these birds are likely to significantly contribute to circulation of IAVs. Thus, we 1) estimated snow goose infection prevalence by summarizing > 5,000 snow goose surveillance records, 2) experimentally infected snow geese with a low pathogenic IAV (H4N6) to assess susceptibility and infection dynamics and …

Social Structure Defines Spatial Transmission Of African Swine Fever In Wild Boar, Kim M. Pepin, Andrew J. Golnar, Tomasz Podgórski

United States Department of Agriculture Wildlife Services: Staff Publications

The spatial spread of infectious disease is determined by spatial and social processes such as animal space use and family group structure. Yet, the impacts of social processes on spatial spread remain poorly understood and estimates of spatial transmission kernels (STKs) often exclude social structure. Understanding the impacts of social structure on STKs is important for obtaining robust inferences for policy decisions and optimizing response plans. We fit spatially explicit transmission models with different assumptions about contact structure to African swine fever virus surveillance data from eastern Poland from 2014 to 2015 and evaluated how social structure affected inference of …

Welfare Performance Of Three Foothold Traps For Capturing North American River Otters Lontra Canadensis, Matthew J. Lovallo, H. B. White, J. D. Erb, M. S. Peek, Thomas J. Deliberto

United States Department of Agriculture Wildlife Services: Staff Publications

Foothold traps are effective tools for the live capture and restraint of wildlife for management and research. Successful river otter Lontra canadensis restoration programs throughout North America used them extensively. Restoration programs used a variety of methods and models of foothold traps, but comprehensive efforts to describe and quantify injuries associated with river otter captures have been limited. We evaluated injuries of river otters caught in three commercially available models of foothold traps including the number 11 double long-spring with standard jaws, the number 11 double long-spring with double jaws, and the number 2 coil-spring trap. Based on examinations of …

Occurrence Of Mesocarnivores In Montane Sky Islands: How Spatial And Temporal Overlap Informs Rabies Management In A Regional Hotspot, Amanda M. Veals, John Koprowski, David L. Bergman, Kurt C. Vercauteren, David B. Wester

United States Department of Agriculture Wildlife Services: Staff Publications

Interspecific interactions among mesocarnivores can influence community dynamics and resource partitioning. Insights into these interactions can enhance understanding of local ecological processes that have impacts on pathogen transmission, such as the rabies lyssavirus. Host species ecology can provide an important baseline for disease management strategies especially in biologically diverse ecosystems and heterogeneous landscapes. We used a mesocarnivore guild native to the southwestern United States, a regional rabies hotspot, that are prone to rabies outbreaks as our study system. Gray foxes (Urocyon cinereoargenteus), striped skunks (Mephitis mephitis), bobcats (Lynx rufus), and coyotes (Canis latrans) share large portions of their geographic ranges …

Scaup Depredation On Arkansas Baitfish And Sportfish Aquaculture, Stephen A. Clements, Brian S. Dorr, J. Brian Davis, Luke A. Roy, Carole R. Engle, Katie C. Hanson-Dorr, Anita M. Kelly

United States Department of Agriculture Wildlife Services: Staff Publications

Lesser scaup (Aythya affinis) and greater scaup (A. marila), hereafter scaup, consume a variety of aquatic invertebrates, plants, and occasionally small fish. Scaup have foraged on commercial aquaculture farms in the southern United States for decades. However, the types, abundance, and rate of fish exploitation by scaup on baitfish and sportfish farms are not well documented. Thus, information is needed to understand how fish and other foods influence scaup use of aquatic resources, and any potential economic effects of depredation of fish. From November–March in winters 2016–2017 and 2017–2018, we conducted 1,458 pond surveys to estimate …