Life Sciences Commons^™

Variation In Reversal Learning By Three Generalist Mesocarnivores, Lauren A. Stanton, Eli S. Bridge, Joost Huizinga, Shylo R. Johnson, Julie K. Young, Sarah Benson‑Amram

United States Department of Agriculture Wildlife Services: Staff Publications

Urbanization imposes novel challenges for wildlife, but also provides new opportunities for exploitation. Generalist species are commonly found in urban habitats, but the cognitive mechanisms facilitating their successful behavioral adaptations and exploitations are largely under-investigated. Cognitive flexibility is thought to enable generalists to be more plastic in their behavior, thereby increasing their adaptability to a variety of environments, including urban habitats. Yet direct measures of cognitive flexibility across urban wildlife are lacking. We used a classic reversal-learning paradigm to investigate the cognitive flexibility of three generalist mesocarnivores commonly found in urban habitats: striped skunks (Mephitis mephitis), raccoons ( …

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 …

Rabies Post-Exposure Healthcare-Seeking Behaviors And Perceptions: Results From A Knowledge, Attitudes, And Practices Survey, Uganda, 2013, Sarah C. Bonaparte, Laura Adams, Barnabas Bakamutumaho, Galileu Barbosa Costa, Julie M. Cleaton, Amy Gilbert, Modupe Osinubi, Emily G. Pieracci, Sergio Recuenco, Victor Tugumizemu, Joseph Wamala, Ryan M. Wallace

United States Department of Agriculture Wildlife Services: Staff Publications

Background Rabies is a viral disease of animals and people causing fatal encephalomyelitis if left untreated. Although effective pre- and post-exposure vaccines exist, they are not widely available in many endemic countries within Africa. Since many individuals in these countries remain at risk of infection, post-exposure healthcare-seeking behaviors are crucial in preventing infection and warrant examination.

Methodology A rabies knowledge, attitudes, and practices survey was conducted at 24 geographically diverse sites in Uganda during 2013 to capture information on knowledge concerning the disease, response to potential exposure events, and vaccination practices. Characteristics of the surveyed population and of the canine-bite …

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. …

H7n1 Low Pathogenicity Avian Influenza Viruses In Poultry In The United States During 2018, Dong-Hun Lee, Mary Lea Killian, Thomas J. Deliberto, Xiu-Feng Wan, Li Lei, David E. Swayne, Mia Kim Torchetti

United States Department of Agriculture Wildlife Services: Staff Publications

Here, we report three detections of H7N1 low pathogenicity avian influenza viruses (LPAIV) from poultry in Missouri (n¼2) and Texas (n¼1) during February and March 2018. Complete genome sequencing and comparative phylogenetic analysis suggest that the H7 LPAIV precursor viruses were circulating in wild birds in North America during the fall and winter of 2017 and spilled over into domestic poultry in Texas and Missouri independently during the spring of 2018.

RESUMEN. Nota de investigacio´n—Virus de la influenza aviar de baja patogenicidad H7N1 en avicultura, Estados Unidos, 2018. En este art´ıculo se reportan tres detecciones del virus de influenza aviar …

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 …

Dietary Flexibility Of Wood Storks In Response To Human-Induced Rapid Environmental Change, Betsy A. Evans, Jessica A. Klassen, Dale E. Gawlik

United States Department of Agriculture Wildlife Services: Staff Publications

Human-induced rapid environmental change (HIREC) has altered landscape processes and negatively impacted many species globally. Some of the most dramatic changes have been in wetlands where flows have been disrupted, and new wetlands have been created to retain runoff. In response to disrupted natural wetland conditions, Wood Stork (Mycteria americana) populations in South Florida have significantly declined over the past several decades. Despite the well-documented sensitivity of Wood Storks to natural wetland conditions, Wood Storks are often observed foraging in roadside created wetlands; however, the availability of prey in created wetlands is currently unknown. We sampled natural and created wetlands …

Space Use In Free-Ranging Canids: Are Gonadal Hormones Required For Territory Maintenance?, Eric M. Gese, Patricia A. Terletzky

United States Department of Agriculture Wildlife Services: Staff Publications

Fertility control among carnivores has been used to reduce depredations on livestock and wild neonates, population control, modify behavior, inhibit genetic introgression, and reduce human–wildlife conflicts. Although there is considerable knowledge on techniques to sterilize carnivores, there is little information concerning how the absence of gonadal hormones influences behavior, space use, and survival of wild canids. We examined territorial fidelity, home-range size and overlap, and survival of 179 surgically sterilized free-ranging canids (124 coyotes (Canis latrans Say, 1823), 55 coyote – red wolf (Canis rufus Audubon and Bachman, 1851) hybrids) with gonadal hormones present (tubal-ligated females (n = 70), vasectomized …

The Consequences Of Predators Without Prey, Mitchell A. Parsons, Thomas M. Newsome, Julie K. Young

United States Department of Agriculture Wildlife Services: Staff Publications

Rapid and ongoing environmental change is leading to scenarios where marine and terrestrial predators are persisting without prey, either by scavenging or using anthropogenic foods. Despite investigations into the effects of predator presence or absence on prey behavior and ecology, little research has assessed the effect of prey absence on predators. Here, we synthesize research on scavenging and the use of anthropogenic resources by marine and terrestrial predators; hypothesize how the use of these resources may change predator behavior with respect to their social structure, space use, life history, and individual behavioral traits; and illustrate how these changes are likely …

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 …

Improving Evaluation Of Nonlethal Tools For Carnivore Management And Conservation: Evaluating Fladry To Protect An Endangered Species From A Generalist Mesocarnivore, R. M. Windell, L. L. Bailey, J. K. Young, T. M. Livieri, D. A. Eads, S. W. Breck

United States Department of Agriculture Wildlife Services: Staff Publications

Carnivore conservation and management are global research priorities focused on reversing population declines of imperiled species and identifying more effective and humane management of generalist carnivores with thriving populations. Nonlethal methods to mitigate conflict are increasingly used to advance conservation objectives; however, there is limited knowledge about the effectiveness of many nonlethal methods. We tested a nonlethal tool (fladry), that serves as a barrier to deter wolves Canis lupus and coyotes Canis latrans, for its efficacy at preventing coyotes from using prairie dog Cynomys ludovicianus colonies, the primary prey for critically endangered black-footed ferrets Mustela nigripes. We used …

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, …

Strategic Considerations For Invasive Species Managers In The Utilization Of Environmental Dna (Edna): Steps For Incorporating This Powerful Surveillance Tool, Jeffrey Morisette, Stanley Burgiel, Kelsey Brantley, Wesley M. Daniel, John Darling, Jeanette Davis, Thomas Franklin, Keith Gaddis, Margaret Hunter, Richard Lance, Tracy Leskey, Yale Passamaneck, Antoinette Piaggio, Brian Rector, Adam Sepulveda, Melissa Smith, Carol A. Stepien, Taylor Wilcox

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive species surveillance programs can utilize environmental DNA sampling and analysis to provide information on the presence of invasive species. Wider utilization of eDNA techniques for invasive species surveillance may be warranted. This paper covers topics directed towards invasive species managers and eDNA practitioners working at the intersection of eDNA techniques and invasive species surveillance. It provides background information on the utility of eDNA for invasive species management and points to various examples of its use across federal and international programs. It provides information on 1) why an invasive species manager should consider using eDNA, 2) deciding if eDNA can …

Reproductive Trade-Offs In The Colorado Checkered Whiptail Lizard (Aspidoscelis Neotesselatus): An Examination Of The Relationship Between Clutch And Follicle Size, Hannah E. Caracalas, S. S. French, S. B. Hudson, B. M. Kluever, A. C. Webb, D. Eifler, A. J. Lehmicke, Lise M. Aubry

United States Department of Agriculture Wildlife Services: Staff Publications

Life history theory predicts that there should be an inverse relationship between offspring size and number, because individuals cannot simultaneously maximize both when resources are limited. Although extensively studied in avian species, the occurrence and determinants of reproductive tradeoffs in oviparous reptiles are far less understood, particularly in parthenogenetic species. We studied this trade-off in the Colorado Checkered Whiptail, Aspidoscelis neotesselatus, a female-only parthenogenetic lizard. Using data previously collected in 2018 and 2019, we tested for clutch and egg size trade-offs and determined whether this relationship could be influenced by female size and aspects of physiological condition. Physiological condition …

Differing Alterations Of Odor Volatiles Among Pathogenic Stimuli, Patrick Millet, Talia Martin, Maryanne Opiekun, Gary K. Beauchamp, Bruce A. Kimball

United States Department of Agriculture Wildlife Services: Staff Publications

Alterations of the volatile metabolome (the collection of volatiles present in secretions and other emanations) that occur in response to inflammation can be detected by conspecifics and chemometric analyses. Using a model system where mouse urinary metabolites are altered by treatment with lipopolysaccharide (found in the outer cell membrane of gram-negative bacteria), we hypothesized that alteration of body odor volatiles will vary according to the pathogen responsible for inducing the inflammation. We tested this hypothesis by treating mice with different immunogens that engage different immune signaling pathways. Results suggest that alterations of body odor volatiles resulting from inflammation do contain …

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 …

Sars-Cov-2 Exposure In Wild White-Tailed Deer (Odocoileus Virginianus), Jeffrey C. Chandler, Sarah N. Bevins, Jeremy W. Ellis, Timothy J. Linder, Rachel M. Tell, Melinda Jenkins-Moore, J. Jeffrey Root, Julianna B. Lenoch, Suelee Robbe-Austerman, Thomas J. Deliberto, Tom Gidlewski, Mia Kim Torchetti, Susan A. Shriner

United States Department of Agriculture Wildlife Services: Staff Publications

Widespread human SARS-CoV-2 infections combined with human–wildlife interactions create the potential for reverse zoonosis from humans to wildlife. We targeted white-tailed deer (Odocoileus virginianus) for serosurveillance based on evidence these deer have angiotensin-converting enzyme 2 receptors with high affinity for SARS-CoV-2, are permissive to infection, exhibit sustained viral shedding, can transmit to conspecifics, exhibit social behavior, and can be abundant near urban centers. We evaluated 624 prepandemic and postpandemic serum samples from wild deer from four US states for SARS-CoV-2 exposure. Antibodies were detected in 152 samples (40%) from 2021 using a surrogate virus neutralization test. A subset of samples …

Impact Of Covid-19 On The Us And Texas Economy: A General Equilibrium Approach, Lirong Liu, Steven S. Shwiff, Stephanie A. Shwiff, Maryfrances Miller

United States Department of Agriculture Wildlife Services: Staff Publications

This paper examines the impact of COVID-19 on the US and Texas economy using a computable general equilibrium model, REMI PI+. We consider three scenarios based on economic forecasts from various sources, including the University of Michigan’s RSQE (Research Seminar in Quantitative Economics), IMF, and the Wi orld Bank. We report a GDP loss of $106 million (a 6% decline) with 1.2 million jobs lost (6.6%) in Texas in 2020. At the national level, GDP loss is $996 billion (a 5% decline) with 11.5 million jobs lost (5.5%) in the same year. By 2026, the aggregate total GDP loss in …

Using Object-Based Image Analysis To Detect Laughing Gull Nests, Benjamin F. Martini, Douglas A. Miller

United States Department of Agriculture Wildlife Services: Staff Publications

Remote sensing has long been used to study wildlife; however, manual methods of detecting wildlife in aerial imagery are often time-consuming and prone to human error, and newer computer vision techniques have not yet been extensively applied to wildlife surveys. We used the object-based image analysis (OBIA) software eCognition to detect laughing gull (Leucophaeus atricilla) nests in Jamaica Bay as part of an ongoing monitoring effort at the John F. Kennedy International Airport. Our technique uses a combination of high resolution 4-band aerial imagery captured via manned aircraft with a multispectral UltraCam Falcon M2 camera, LiDAR point cloud data, and …

Detection Of Two Dissimilar Chronic Wasting Disease Isolates In Two Captive Rocky Mountain Elk (Cervus Canadensis) Herds: Two Distinctive Chronic Wasting Disease Isolates Identified In Captive Elk, Tracy A. Nichols, Eric M. Nicholson, Yihui Liu, Wanyin Tao, Terry R. Spraker, Michael Lavelle, Justin W. Fischer, Qingzhong Kong, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Chronic wasting disease (CWD) continues to spread in both wild and captive cervid herds in North America and has now been identified in wild reindeer and moose in Norway, Finland and Sweden. There is limited knowledge about the variety and characteristics of isolates or strains of CWD that exist in the landscape and their implications on wild and captive cervid herds. In this study, we evaluated brain samples from two captive elk herds that had differing prevalence, history and timelines of CWD incidence. Site 1 had a 16-year history of CWD with a consistently low prevalence between 5% and 10%. …

Environmental Dna For Conservation, Antoinette J. Piaggio

United States Department of Agriculture Wildlife Services: Staff Publications

Biodiversity must be documented before it can be conserved. However, it may be difficult to document species with few individuals (Thompson, 2013; Goldberg et al., 2016), thus it requires a multitude of tools to detect species that occur in low numbers or are elusive (see the various chapters in this volume). One tool that has become useful for conservation efforts utilizes environmental DNA, which is DNA shed into the environment by organisms (eDNA; Taberlet et al., 2018). Typically this involves taking environmental samples such as soil, water, air, or using biological surrogates for sampling biodiversity (e.g. leeches, sponges, carrion flies, …

Allometric Regression Of Snake Body Length From Head Image Measurements, Shane R. Siers

United States Department of Agriculture Wildlife Services: Staff Publications

As in many fields of wildlife research and management, camera devices and photogrammetry have become an integral part of the toolkit for exploring otherwise‐unseen aspects of the biology, behavior, and control of the invasive brown treesnake (Boiga irregularis) on Guam. Because brown treesnakes are cryptic and nocturnal, and nearly all aspects of their ecology are influenced by snake size, methods are needed to estimate snake size from images captured by infrared wildlife cameras. Unfortunately, it is difficult to capture images of an entire snake’s length at a controlled distance from a simple camera setup. Here, I describe the …