Veterinary Microbiology and Immunobiology Commons^™

Intercontinental Movement Of Highly Pathogenic Avian Influenza A(H5n1) Clade 2.3.4.4 Virus To The United States, 2021, Sarah N. Bevins, Susan A. Shriner, James C. Cumbee Jr., Krista E. Dilione, Kelly E. Douglass, Jeremy W. Ellis, Mary Lea Killian, Mia K. Torchetti, Julianna B. Lenoch

United States Department of Agriculture Wildlife Services: Staff Publications

We detected Eurasian-origin highly pathogenic avian influenza A(H5N1) virus belonging to the Gs/GD lineage, clade 2.3.4.4b, in wild waterfowl in 2 Atlantic coastal states in the United States. Bird banding data showed widespread movement of waterfowl within the Atlantic Flyway and between neighboring flyways and northern breeding grounds.

Individual Trophic Niche Specialization In American Beaver (Castor Canadensis), Jimmy Taylor, Robert Francis, Scott Rush, Bronson Strickland, Guiming Wang

United States Department of Agriculture Wildlife Services: Staff Publications

The American beaver (Castor canadensis) has been described as a choosy generalist at the species/population scale, yet observational studies have shown little variation in diet among individuals. We compared isotopic values of δ¹³C or δ¹⁵N taken from hair of 32 beaver, representing seven colonies in northern Alabama, USA to determine 1) if colonies of beaver show overlap in isotopic niche width as a result of the similar use of food resources and 2) if individual trophic niche specialization occurs within colonies. Total Trophic Niche Width varied across the wetland with the widest being twice …

Editorial: Special Issue “Innovative Techniques And Approaches In The Control And Prevention Of Rabies Virus”, Amy T. Gilbert, Ryan M. Wallace, Charles E. Rupprecht

United States Department of Agriculture Wildlife Services: Staff Publications

Rabies is an ancient lethal scourge that has plagued humankind for centuries. Globally, 60,000 human deaths are estimated to occur each year from rabies virus (RABV) transmission in domestic dogs, mostly affecting children. While rabies is recognized as a neglected disease, there is cause for optimism in the context of growing global recognition, collaboration and commitment to advance a tripartite agenda to eliminate human deaths transmitted from rabid dogs by 2030, also known as “Zero By Thirty” (ZBT). Nevertheless, the ZBT goal must also confront competing challenge(s) of tracking and mitigating human morbidity and mortality during a global pandemic caused …

Can We Use Antipredator Behavior Theory To Predict Wildlife Responses To High-Speed Vehicles?, Ryan B. Lunn, Bradley Blackwell, Travis L. Devault, Esteban Fernández-Juricic

United States Department of Agriculture Wildlife Services: Staff Publications

Animals seem to rely on antipredator behavior to avoid vehicle collisions. There is an extensive body of antipredator behavior theory that have been used to predict the distance/time animals should escape from predators. These models have also been used to guide empirical research on escape behavior from vehicles. However, little is known as to whether antipredator behavior models are appropriate to apply to an approaching high-speed vehicle scenario. We addressed this gap by (a) providing an overview of the main hypotheses and predictions of different antipredator behavior models via a literature review, (b) exploring whether these models can generate quantitative …

Antibody Dependent Enhancement Of Infectious Bronchitis Virus In Poultry, Zachary Hamilton, Barry Simpson, Donald L. Reynolds

UCARE: Research Products

Avian infectious bronchitis (IB) is a coronavirus infection of chickens that causes respiratory disease and reproductive problems in chickens. Currently, there are vaccines that are effective against IB. However, new variants and strains of avian infectious bronchitis virus (IBV) routinely emerge. A vaccine that is not the same strain as the virus is not completely effective in protecting against other variants because the vaccine will not allow the host antibodies to completely neutralize the strain. This is a problem because it makes IB difficult to control and diagnose.

Antibody-dependent enhancement (ADE) is a phenomenon whereby non-neutralizing antibodies, or low levels …

Understanding Continent-Wide Variation In Vulture Ranging Behavior To Assess Feasibility Of Vulture Safe Zones In Africa: Challenges And Possibilities, Adam Kane, Ara Monadjem, H. K.Ortwin Aschenborn, Keith Bildstein, André Botha, Claire Bracebridge, Evan R. Buechley, Ralph Buij, John P. Davies, Maria Diekmann, Colleen T. Downs, Nina Farwig, Toby Galligan, Gregory Kaltenecker, Chris Kelly, Ryno Kemp, Holger Kolberg, Monique L. Mackenzie, John Mendelsohn, Msafiri Mgumba, Ran Nathan, Aaron Nicholas, Darcy Ogada, Morgan Pfeiffer, W. Louis Phipps, Matteuns D. Pretorius, Sascha Rösner, Dana G. Schabo, Gabriel Lita Shatumbu, Orr Spiegel, Lindy J. Thompson, Jan A. Venter, Munir Virani, Kerri Wolter, Corinne J. Kendall

United States Department of Agriculture Wildlife Services: Staff Publications

Protected areas are intended as tools in reducing threats to wildlife and preserving habitat for their long-term population persistence. Studies on ranging behavior provide insight into the utility of protected areas. Vultures are one of the fastest declining groups of birds globally and are popular subjects for telemetry studies, but continent-wide studies are lacking. To address how vultures use space and identify the areas and location of possible vulture safe zones, we assess home range size and their overlap with protected areas by species, age, breeding status, season, and region using a large continent-wide telemetry datasets that includes 163 individuals …

European Starling Use Of Nest Boxes Relative To Human Disturbance, Bradley Blackwell, Bruce N. Buckingham, Morgan B. Pfeiffer

United States Department of Agriculture Wildlife Services: Staff Publications

gars and to engine and flight surfaces of moored aircraft. We questioned whether consistent removal of nest material would negatively affect use of a nest site, measured by a reduction in material accumulation. We conducted our study on a 2,200-ha site in Erie County, Ohio, USA (41° 22’ N, 82° 41’ W), from April 15 through June 2, 2020. We used 120 wooden nest boxes on utility poles, protected by an aluminum predator guard below the box. Our treatments included (1) twice weekly, repeated nest material removal (RMR; n = 40 nest boxes); (2) complete nest removal, but only after …

Economic Consequences Of The Wolf Comeback In The Western United States, Dana Hoag, Stewart W. Breck, Kevin Crooks, Becky Niemiec

United States Department of Agriculture Wildlife Services: Staff Publications

Gray wolves were eradicated from most of the United States in the 1940’s but have made a comeback in parts of their historic range over the last two decades. First reintroduced into the Greater Yellowstone Ecosystem and central Idaho in the mid-1990’s, wolves have subsequently dispersed into at least 7 western states. Coloradoans became the latest state to take interest in bolstering wolf populations, as residents passed a ballot initiative in November 2020 to reintroduce a self-sustaining population of gray wolves by the end of 2023. Conflicts between people in rural areas that might incur costs (such as livestock loss) …

A Review Of The Impacts Of Invasive Wild Pigs On Native Vertebrates, Matthew T. Mcdonough, Stephen S. Ditchkoff, Mark D. Smith, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

The wild pig (Sus scrofa) is a successful invasive species that has become well established outside of its native range in Eurasia. The invasive wild pig is the result of released or escaped domesticated livestock becoming feral, or Eurasian boar introduced for hunting purposes. The global spread of wild pigs has recently been exacerbated in some areas, such as the USA, by anthropogenically assisted dispersal. Once established in novel ecosystems, wild pigs have the potential to have significant negative impacts on the ecosystem, and the scientific literature is replete with examples. It is generally accepted that wild pigs …

Use Of A Direct, Rapid Immunohistochemical Test For Diagnosis Of Rabies Virus In Bats, Charles E. Rupprecht, Lolita Van Pelt, April D. Davis, Richard B. Chipman, David L. Bergman

United States Department of Agriculture Wildlife Services: Staff Publications

Rabies, a zoonotic encephalitis due to transmission of a lyssavirus, such as rabies virus (RABV), has the highest case fatality of any infectious disease. A global program for the elimination of human rabies caused by dogs is proposed for realization by 2030. Sensitive, specific, and inexpensive diagnostic tests are necessary for enhanced surveillance to detect infection, inform public health and veterinary professionals during risk assessments of exposure, and support overall programmatic goals. Multiple laboratory techniques are used to confirm a suspect case of rabies. One method for the detection of lyssavirus antigens within the brain is the direct rapid immunohistochemical …

Optimizing Management Of Invasions In An Uncertain World Using Dynamic Spatial Models, Kim M. Pepin, Amy J. Davis, Rebecca S. Epanchin-Niell, Andrew M. Gormley, Joslin L. Moore, Timothy J. Smyser, H. Bradley Shaffer, William L. Kendall, Katriona Shea, Michael C. Runge, Sophie Mckee

United States Department of Agriculture Wildlife Services: Staff Publications

Dispersal drives invasion dynamics of nonnative species and pathogens. Applying knowledge of dispersal to optimize the management of invasions can mean the difference between a failed and a successful control program and dramatically improve the return on investment of control efforts. A common approach to identifying optimal management solutions for invasions is to optimize dynamic spatial models that incorporate dispersal. Optimizing these spatial models can be very challenging because the interaction of time, space, and uncertainty rapidly amplifies the number of dimensions being considered. Addressing such problems requires advances in and the integration of techniques from multiple fields, including ecology, …

An Efficient Method Of Evaluating Multiple Concurrent Management Actions On Invasive Populations, Amy J. Davis, Randy Farrar, Brad Jump, Parker Hall, Travis Guerrant, Kim M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

Evaluating the efficacy of management actions to control invasive species is crucial for maintaining funding and to provide feedback for the continual improvement of management efforts. However, it is often difficult to assess the efficacy of control methods due to limited resources for monitoring. Managers may view effort on monitoring as effort taken away from performing management actions. We developed a method to estimate invasive species abundance, evaluate management effectiveness, and evaluate population growth over time from a combination of removal activities (e.g., trapping, ground shooting) using only data collected during removal efforts (method of removal, date, location, number of …

Economics Of Cormorant Predation On Catfish Farms, Carole Engle, Ganesh Kumar, Terrel Christie, Brian S. Dorr, Brian Davis, Luke Roy, Anita Kelly

United States Department of Agriculture Wildlife Services: Staff Publications

The Double-crested Cormorant is the primary avian predator on catfish farms causing significant economic losses primarily due to 1) on-farm expenditures related to bird-management activities and 2) value of the catfish lost to cormorants. This comprehensive economic study quantified these two economic effects by surveying catfish farms in the delta regions of Mississippi and Arkansas. On-farm expenditures for bird scaring were used to quantify bird-management costs. Economic losses from fish consumed by cormorants were quantified by evaluating data from field studies of the abundance, distribution, and diet of cormorants in the Mississippi delta. This study found that catfish farmers …

Aboveground Carbon Responses To Experimental And Natural Hurricane Impacts In A Subtropical Wet Forest In Puerto Rico, Hervé Chevalier, Nicholas V.L. Brokaw, Sheila E. Ward, Jess K. Zimmerman, Aaron B. Shiels, John Bithorn, Samuel Matta Carmona

United States Department of Agriculture Wildlife Services: Staff Publications

Climate change and disturbance make it difficult to project long-term patterns of carbon sequestration in tropical forests, but large ecosystem experiments in these forests can inform predictions. The Canopy Trimming Experiment (CTE) manipulates two key components of hurricane disturbance, canopy openness and detritus deposition, in a tropical forest in Puerto Rico. We documented how the CTE and a real hurricane affected tree recruitment, biomass, and aboveground carbon storage over 15 years. In the CTE treatments, we trimmed branches, but we did not fell trees. We expected that during the 14-year period after initial canopy trimming, regrowth of branches and stems …

Behavioral States In Space And Time: Understanding Landscape Use By An Invasive Mammal, Steven M. Gray, John M. Humphreys, Robert A. Montgomery, Dwayne R. Etter, Kurt C. Vercauteren, Daniel B. Kramer, Gary J. Roloff

United States Department of Agriculture Wildlife Services: Staff Publications

Animal movement models can be used to understand species behavior and assist with implementation of management activities. We explored behavioral states of an invasive wild pig (Sus scrofa) population that recently colonized central Michigan, USA, 2014–2018. To quantify environmental factors related to wild pig movement ecology and spatio‐temporal landscape use, we predicted wild pig behavioral states relative to land cover type, landscape structure (i.e., edge and patch cohesion), and weather conditions. We used global positioning system (GPS)‐collars and monitored 8 wild pigs from 2014–2018. We fit local convex hulls and calculated movement metrics revealing 3 wild pig behavioral states (resting, …

Accounting For Animal Movement Improves Vaccination Strategies Against Wildlife Disease In Heterogeneous Landscapes, Katherine M. Mcclure, Guillaume Bastille-Rousseau, Amy J. Davis, Carolyn A. Stengel, Kathleen M. Nelson, Richard B. Chipman, George Wittemyer, Zaid Abdo, Amy Gilbert, Kim M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

Oral baiting is used to deliver vaccines to wildlife to prevent, control, and eliminate infectious diseases. A central challenge is how to spatially distribute baits to maximize encounters by target animal populations, particularly in urban and suburban areas where wildlife such as raccoons (Procyon lotor) are abundant and baits are delivered along roads. Methods from movement ecology that quantify movement and habitat selection could help to optimize baiting strategies by more effectively targeting wildlife populations across space. We developed a spatially explicit, individual-based model of raccoon movement and oral rabies vaccine seroconversion to examine whether and when baiting …

Rodents In Agriculture: A Broad Perspective, Gary Witmer

United States Department of Agriculture Wildlife Services: Staff Publications

The largest taxonomic group of mammals is rodents, with over 2200 species known around the world [1]. More recently, it was stated that over 2500 species exist [2]. Many species exist on all continents, with the exception of Antarctica. Rodents have adapted to all ecosystems of the world, including tundra, alpine, temperate forests, grasslands, arid regions, and aquatic systems. They provide many ecosystem functions, including soil aeration and mixing, seed and spore dispersal, vegetation succession, and being an important food source for predatory animals. Some species of rodents are even consumed by people in some parts of the world. Most …

Transmission Of Antibiotic Resistance At The Wildlife-Livestock Interface, Shinyoung Lee, Peixin Fan, Ting Liu, Anni Yang, Raoul K. Boughton, Kim M. Pepin, Ryan S. Miller, Kwangcheol Casey Jeong

United States Department of Agriculture Wildlife Services: Staff Publications

Antibiotic-resistant microorganisms (ARMs) are widespread in natural environments, animals (wildlife and livestock), and humans, which has reduced our capacity to control life threatening infectious disease. Yet, little is known about their transmission pathways, especially at the wildlife-livestock interface. This study investigated the potential transmission of ARMs and antibiotic resistance genes (ARGs) between cattle and wildlife by comparing gut microbiota and ARG profiles of feral swine (Sus scrofa), coyotes (Canis latrans), cattle (Bos taurus), and environmental microbiota. Unexpectedly, wild animals harbored more abundant ARMs and ARGs compared to grazing cattle. Gut microbiota of cattle was …

No Panacea Attractant For Wild Pigs (Sus Scrofa), But Season And Location Matter, Nathan P. Snow, Caitlin A. Kupferman, Michael J. Lavelle, Kim M. Pepin, Madeline H. Melton, Whitney J. Gann, Kurt C. Vercauteren, James C. Beasley

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) are a prolific invasive species throughout many regions of the world that cause extensive economic and environmental damage. Trapping is a common strategy for reducing their populations with baits (i.e., food) and attractants (e.g., scents) used to lure wild pigs into traps. However, there is little information on which scent attractants may attract wild pigs more readily and rapidly across regions and seasons. We examined 60 scent attractants for wild pigs that could be used to increase trapping success across three seasons (winter, spring, and fall) and in two geographic regions, including a warm …

Summer Habitat Use And Movements Of Invasive Wild Pigs (Sus Scrofa) In Canadian Agro-Ecosystems, Corey J. Kramer, Melanie R. Boudreau, Ryan S. Miller, Ryan Powers, Kurt C. Vercauteren, Ryan K. Brook

United States Department of Agriculture Wildlife Services: Staff Publications

Resource selection informs understanding of a species’ ecology and is especially pertinent for invasive species. Since introduced to Canada, wild pigs (Sus scrofa Linnaeus, 1978) remain understudied despite recognized negative impacts on native and agricultural systems globally. Elsewhere in North America, pigs typically use forests and forage in agricultural crops. We hypothesized Canadian wild pigs would behave similarly, and using GPS locations from 15 individuals, we examined diel and seasonal resource selection and movement in the Canadian prairie region. Forests were predominately selected during the day, while corn (Zea mays L.), oilseeds, and wheat (Triticum aestivum L.) …

Predation Thresholds For Reintroduction Of Native Avifauna Following Suppression Of Invasive Brown Treesnakes On Guam, Robert M. Mcelderry, Eben H. Paxton, Andre V. Nguyen, Shane R. Siers

United States Department of Agriculture Wildlife Services: Staff Publications

The brown treesnake (BTS) (Boiga irregularis) invasion on Guåhan (in English, Guam) led to the extirpation of nearly all native forest birds. In recent years, methods have been developed to reduce BTS abundance on a landscape scale. To help assess the prospects for the successful reintroduction of native birds to Guåhan following BTS suppression, we modeled bird population persistence based on their life history characteristics and relative sensitivity to BTS predation. We constructed individual-based models and simulated BTS predation in hypothetical founding populations for each of seven candidate bird species. We represented BTS predation risk in two steps: …

Conserving Endangered Black-Footed Ferrets: Biological Threats, Political Challenges, And Lessons Learned, Travis M. Livieri, Steven C. Forrest, Marc R. Matchett, Stewart Breck

United States Department of Agriculture Wildlife Services: Staff Publications

There may be few stories in the annals of wildlife management that are as dramatic as the near demise and comeback of the black-footed ferret (Mustela nigripes). Endemic only to North America, this charming little carnivore found only in the continent’s central grasslands was hardly known to science until the mid-20th century. By then, vast colonies of the prey it depended on for food and shelter, the prairie dog (Cynomys spp.), had been wiped out through disease (sylvatic plague) and an agricultural industry with little tolerance for burrowing and grazing rodents. At its low point, the species’ …

Susceptibility Of Wild Canids To Sars-Cov-2, Stephanie M. Porter, Aim E. Hartwig, Helle Bielefeldt-Ohmann, Angela M. Bosco-Lauth, J. Jeffrey Root

United States Department of Agriculture Wildlife Services: Staff Publications

We assessed 2 wild canid species, red foxes (Vulpes vulpes) and coyotes (Canis latrans), for susceptibility to SARS-CoV-2. After experimental inoculation, red foxes became infected and shed infectious virus. Conversely, experimentally challenged coyotes did not become infected; therefore, coyotes are unlikely to be competent hosts for SARS-CoV-2.

Throughout the COVID-19 pandemic, multiple instances of natural infections with SARS-CoV-2 have been reported in pet dogs, likely after exposure to an infected human (1–3). Domestic dogs appear to be minimally susceptible to SARS-CoV-2, as indicated by experimental inoculations resulting in reverse transcription PCR–positive samples and low titer antibody responses but no clinical …

Predicting Consistent Foraging Ecologies Of Migrating Waterbirds: Using Stable Isotope And Parasite Measurements As Indicators Of Landscape Use, Kate L. Sheehan, Brian S. Dorr, Stephen A. Clements, Terrel W. Christie, Katie Hanson-Dorr, Scott A. Rush, J. Brian Davis

United States Department of Agriculture Wildlife Services: Staff Publications

The emergence of novel human pathogens is frequently linked with zoonotic events and human-wildlife interactions that promote disease transmission. Consequently, surveillance of wildlife populations for candidate diseases that could spread to humans is beneficial, but requires widespread collections of numerous samples. A legitimate means to acquire large sample sizes of waterfowl is through cooperation between researchers and hunters, who also work in concert with natural resource managers, landowners, and agricultural entities -e.g., aquaculture facilities. In addition to understanding the occurrence and spread of parasites and pathogens by birds, these samples can be used to answer questions about the ecology of …

Economic Damages Of Wild Pigs In Non-Traditional Areas: From The Fairway To The After Life, Sophie Mckee, Julie Elser, Maryfrances Miller, Lirong Liu, Ryan Miller, Steven S. Shwiff, Stephanie A. Shwiff

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive wild pigs are widely known to cause damage to agricultural properties and commodities, but less has been reported about damages to other types of property. A survey was distributed to golf courses and cemeteries across Texas to explore the extent of damage these properties experience. While both property types reported significant damages, golf courses were found to experience more damage than cemeteries. Using average reported costs and predicted county-level damage, total costs for all golf courses and cemeteries across the state were estimated to exceed $1.6 million USD per year.

Improving Efficiency Of Prairie Dog Surveys By Using A Small Copter Drone, Aaron B. Shiels, J. W. Fischer, Danika Spock, Meagan Allira

United States Department of Agriculture Wildlife Services: Staff Publications

Prairie dogs are an accessible and enjoyed wildlife species in Colorado that require occasional surveys because populations can change abruptly due to plague outbreaks or human-induced control. We evaluated the use of small copter drones at four prairie dog colonies on Open Space and Mountain Parks lands, City of Boulder, to determine if this methodology improves efficiency over ground-based survey methods. We counted prairie dogs and burrows using two types of drones (DJI Matric 210 and Autel Evo II) at altitudes 100', 150', and 400' (burrows only). We recorded video and merged still images into orthomosaics prior to having USDA …

Foot Injuries In Michigan, Usa, Gray Wolves (Canis Lupus), 1992–2014, Daniel J. O'Brien, Dean E. Beyer Jr., Erin Largent, Julie R. Melotti, Caitlin N. Ott-Conn, Donald H. Lonsway, Thomas M. Cooley, Robert Atkinson, Michelle Clayson, Kelly A. Straka

United States Department of Agriculture Wildlife Services: Staff Publications

The range of gray wolves (Canis lupus) in the contiguous US is expanding. Research and monitoring to support population recovery and management often involves capture via foothold traps. A population-level epidemiologic assessment of the effect of trap injuries on wolf survival remains needed to inform management. We describe the baseline rate, type, and severity of foot injuries of wolves born 1992–2013 in Michigan’s Upper Peninsula, evaluate the reliability of field-scoring trap-related injuries, and the effect of injuries on wolf survival. We assessed foot injuries by physical and radiographic exam at postmortem and/or time of capture for 351 wolves using the …

Olfactory Lures In Predator Control Do Not Increase Predation Risk To Birds In Areas Of Conservation Concern, Page Klug, Amy A. Yackel Adams, Robert N. Reed

United States Department of Agriculture Wildlife Services: Staff Publications

Context. Lethal control of predators is often undertaken to protect species of conservation concern. Traps are frequently baited to increase capture efficacy, but baited traps can potentially increase predation risk by attracting predators to protected areas. This is especially important if targeted predators can escape capture due to low trap success. Snake traps using live mouse lures may be beneficial if traps effectively remove snakes in the presence of birds and do not attract additional snakes to the area.

Aims. The present study evaluated whether mouse-lure traps in areas occupied by birds (simulated by deploying birdlure traps) could influence predation …

Wild Pig Removal Reduces Pathogenic Bacteria In Low-Order Streams, Sara A. Bolds, B. Graeme Lockaby, Latif Kalin, Stephen S. Ditchkoff, Mark D. Smith, Kurt Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive wild pig populations have undergone enormous increases in the United States and particularly across the southern U.S. in recent years. High fecundity rates and abilities to adapt quickly to varied habitats have enabled pig populations to become entrenched and difficult to eliminate. The pigs cause many negative impacts on ecosystems including degradation of water quality through infusion of fecal contamination and other non-point source pollutants. Our goal was to determine the effects of pig removal on water quality in streams that were known to be significantly polluted by pig activity Bolds (J Environ Qual 50: 441–453, 2021). We compared …

Relationship Between Reproductive Hormones And Migration Distance In A Polygynous Songbird, The Red‑Winged Blackbird (Agelaius Phoeniceus), Michelle A. Eshleman, Page E. Klug, Esther Morales‑Vega, Björn Wissel, Timothy J. Grelves

United States Department of Agriculture Wildlife Services: Staff Publications

Many bird species migrate to southern overwintering locations to avoid harsh conditions at their breeding grounds, but at the cost of an energetically demanding migration that may delay their spring reproductive development. Previous work on the relationship between migration distance and reproductive readiness has primarily focused on early season baseline testosterone in both males and females. However, for females, testosterone alone may not be the appropriate measurement of reproductive development. Estradiol, a metabolite of testosterone that is essential for breeding behaviors and reproduction, should also be measured. Furthermore, baseline testosterone varies throughout the day and may change due to social …