Digital Commons Network^™

Controllable Factors Affecting Accuracy And Precision Of Human Identification Of Animals From Drone Imagery, Landon R. Jones, Jared A. Elmore, B. Santhana Krishnan, Sathishkumar Samiappan, Kristine O. Evans, Morgan B. Pfeiffer, Brad Blackwell, Raymond Iglay

United States Department of Agriculture Wildlife Services: Staff Publications

Surveying animal populations using drones (unoccupied aircraft systems [UAS]) provides numerous advantages; however, few best practices exist to survey animal communities with drones. Among myriad factors that can affect human identification and counts of animals from drone images, we focused on three factors typically controlled in the study design or by the drone pilot: flight altitude, camera angle, and time of day. Identifying interactions and patterns among these three variables represents an important first step to determining best survey practices. We used a drone to survey known numbers of eight animal decoy species, representing a range of body sizes and …

Factors Affecting The Recovery Of Mexican Wolves In The Southwest United States, Stewart W. Breck, Amy J. Davis, John Oakleaf, David L. Bergman, Jim Devos, J. Paul Greer, Kim M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

1. Recovering and maintaining large carnivore populations is a global conservation challenge that requires better knowledge of the factors affecting their populations, particularly in shared landscapes (i.e. non-protected areas where people occupy and or utilize the land).
2. The Mexican wolf (Canis lupus baileyi) is an endangered wolf subspecies being recovered on shared landscapes in the Southwest United States and Mexico. We used data from the U.S. program to model population growth, evaluate the impact of management removal and illegal killing relative to other demographic factors, and test hypotheses about factors influencing rates of management removal and illegal killing.
3. From …

African Swine Fever, Vienna R. Brown, Julianna B. Lenoch, Courtney F. Bowden

United States Department of Agriculture Wildlife Services: Staff Publications

At the time of writing this chapter, a global pandemic of African swine fever (ASF) is ongoing with the virus having moved from Eastern Europe, Asia, and into the Caribbean—leaving swine production in devastation along the way. Due to the global spread of African swine fever virus (ASFV), the persistence of the virus, and the increasing number of endemic countries, this disease poses an imminent threat of introduction into North America and other countries that are currently ASF free. Throughout the chapter, we reference Eurasian wild boar (Sus scrofa) which are charismatic megafauna that are native to Europe and Asia. …

Spatially Structured Brown-Headed Cowbird Control Measures And Their Effects On Kirtland’S Warbler Long-Term Population Sustainability, Eric A. Margenau, Nathan W. Cooper, Donald J. Brown, Deahn M. Donner, Peter P. Marra, Pat Ryan

United States Department of Agriculture Wildlife Services: Staff Publications

Context: Brown-headed cowbirds (Molothrus ater), through brood parasitism, can exert extrinsic population growth pressures on North American songbirds. Cowbird removal programs may reduce parasitism rates on host species but can be expensive and difficult to implement throughout a host species’ breeding range.

Aim: We estimated cowbird abundance and nest parasitism rates within Kirtland’s warbler (Setophaga kirtlandii) primary breeding range in Michigan, USA, and determined the maximum sustainable parasitism rate for Kirtland’s warblers under several spatially structured cowbird removal designs.

Methods: We conducted point counts to estimate cowbird abundance and monitored nests to quantify nest parasitism rates …

Willingness To Pay For Reintroducing Wolves In A Divided Voting Base, Dana Lk Hoag, Jesse Burkhardt, Benjamin Ghasemi, Stewart W. Breck, Rebecca Niemiec, Kevin Crooks

United States Department of Agriculture Wildlife Services: Staff Publications

Wolves will soon be reintroduced in Colorado based on a statewide ballot initiative that narrowly passed in November 2020. Using an economic choice experiment, we estimate the benefits that wolf introduction might bring to Colorado. We calculated willingness to pay (WTP) for a sustainable wolf population by considering six program attributes: 1) state wolf population, 2) compensation for livestock-related losses, 3) cost-sharing for conflict reduction, 4) number of livestock killed statewide, 5) lethal government control of wolves, and 6) wolf hunting. Respondents who reported they voted yes on the ballot initiative had a positive WTP for a population of 200 …

Can Demographic Histories Explain Long-Term Isolation And Recent Pulses Of Asymmetric Gene Flow Between Highly Divergent Grey Fox Lineages?, Sophie Preckler-Quisquater, Elizabeth M. Kierepka, Dawn M. Reding, Antoinette J. Piaggio, Benjamin N. Sacks

United States Department of Agriculture Wildlife Services: Staff Publications

Secondary contact zones between deeply divergent, yet interfertile, lineages provide windows into the speciation process. North American grey foxes (Urocyon cinereoargenteus) are divided into western and eastern lineages that diverged approximately 1 million years ago. These ancient lineages currently hybridize in a relatively narrow zone of contact in the southern Great Plains, a pattern more commonly observed in smaller-bodied taxa, which suggests relatively recent contact after a long period of allopatry. Based on local ancestry inference with whole-genome sequencing (n = 43), we identified two distinct Holocene pulses of admixture. The older pulse (500–3500 YBP) reflected unidirectional …

Investigation Of Risk Factors For Introduction Of Highly Pathogenic Avian Influenza H5n1 Infection Among Commercial Turkey Operations In The United States, 2022: A Case-Control Study, Kelly A. Patyk, Victoria L. Fields, Andrea L. Beam, Matthew A. Branan, Rachel E. Mcguigan, Alice Green, Mia K. Torchetti, Kristina Lantz, Alexis Freifeld, Katherine Marshall, Amy H. Delgado

United States Department of Agriculture Wildlife Services: Staff Publications

Introduction: The 2022–2023 highly pathogenic avian influenza (HPAI) H5N1 outbreak in the United States (U.S.) is the largest and most costly animal health event in U.S. history. Approximately 70% of commercial farms affected during this outbreak have been turkey farms. Methods: We conducted a case-control study to identify potential risk factors for introduction of HPAI virus onto commercial meat turkey operations. Data were collected from 66 case farms and 59 control farms in 12 states. Univariate and multivariable analyses were conducted to compare management and biosecurity factors on case and control farms. Results: Factors associated with increased risk of infection …

Outbreak Of Epizootic Hemorrhagic Disease In Captive Reindeer (Rangifer Tarandus), Emma H. Torii, Arno Wünschmann, Mia Kim Torchetti, Leo Koster, Albert Van Geelen, Randy Atchison, Anne Rivas

United States Department of Agriculture Wildlife Services: Staff Publications

In September 2020, an outbreak of epizootic hemorrhagic disease occurred in captive reindeer (Rangifer tarandus) and was associated with neurological signs and mortality. Four reindeer died or were euthanized after acute illness over a 12-day period. Affected reindeer displayed abnormal behavior, neurologic signs, lethargy, and/or lameness. The most consistent gross finding was dark red streaks throughout the adrenal gland cortices (4/4). One animal had acute hemorrhage involving the subcutis and skeletal muscles over the ventrolateral body wall and back, and abomasal serosa. Histologically, the most common lesions were adrenal gland cortical hemorrhage (4/4) with necrosis (3/4) and lymphoplasmacytic meningoencephalitis with …

Investigation Of Risk Factors For Introduction Of Highly Pathogenic Avian Influenza H5n1 Virus Onto Table Egg Farms In The United States, 2022: A Case–Control Study, Alice L. Green, Matthew Branan, Victoria L. Fields, Kelly Patyk, Stephanie K. Kolar, Andrea Beam, Katherine Marshall, Rachel Mcguigan, Matthew Vuolo, Alexis Freifeld, Mia Kim Torchetti, Kristina Lantz, Amy H. Delgado

United States Department of Agriculture Wildlife Services: Staff Publications

Introduction: The 2022–2023 highly pathogenic avian influenza (HPAI) H5N1 outbreak in the United States (U.S.) is the most geographically extensive and costly animal health event in U.S. history. In 2022 alone, over 57 million commercial and backyard poultry in 47 U.S. states were affected. Over 75% of affected poultry were part of the commercial table egg production sector. Methods: We conducted a case–control study to identify potential risk factors for introduction of HPAI virus onto commercial table egg operations. Univariate and multivariable analyses were conducted to compare farm characteristics, management, and biosecurity factors on case and control farms. Results: Factors …

Rabies Virus Serosurvey Of The Small Indian Mongoose (Urva Auropunctata) Across Multiple Habitats In Puerto Rico, 2014–21, Are R. Berentsen, Mel J. Rivera-Rodriguez, Fabiola B. Torres-Toledo, Amy J. Davis, Richard Chipman, Amy Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

The small Indian mongoose (Urva auropuncata) is a rabies reservoir in Puerto Rico and accounts for over 70% of reported animal rabies cases annually. The presence of rabies virus-neutralizing antibodies (RVNA) is often used as a tool to measure exposure to rabies virus in wildlife populations. We conducted a serosurvey of mongooses at 11 sites representing six habitat types across Puerto Rico. We collected a serum sample from 464 individual mongooses during 2014–2021. Overall, 80/464 (17.0%; 95% confidence interval, 14.1–20.9%; 55 male, 23 female, and two sexes not recorded) of individual mongooses sampled across all habitats were RVNA …

Evaluation Of Oral Baits And Distribution Methods For Tasmanian Devils (Sarcophilus Harrisii), Sean Dempsey, Ruth J. Pyer, Amy Gilbert, Nicholas M. Fountain-Jones, Jennifer M. Moffat, Sarah Benson-Amram, Timothy J. Smyser, Andrew S. Flies

United States Department of Agriculture Wildlife Services: Staff Publications

Context

Diseases are increasingly contributing to wildlife population declines. Tasmanian devil (Sarcophilus harrisii) populations have locally declined by 82%, largely owing to the morbidity and mortality associated with two independent transmissible devil facial tumours (DFT1 and DFT2). Toxic baits are often used as a management tool for controlling vertebrate pest populations in Australia, but in other areas of the world, oral baits are also used to deliver vaccines or pharmaceuticals to wildlife.

Aim

Our goal was to evaluate the potential use of edible baits as vehicles for vaccine delivery to Tasmanian devils.

Method

We first tested bait palatability with …

Predicting Dispersal And Conflict Risk For Wolf Recolonization In Colorado, Mark A. Ditmer, George Wittemyer, Katherine A. Zeller, Stewart W. Breck, Robert J. Fletcher Jr., Kevin R. Crooks

United States Department of Agriculture Wildlife Services: Staff Publications

1. The colonization of suitable yet unoccupied habitat due to natural dispersal or human introduction can benefit recovery of threatened species. Predicting habitat suitability and conflict potential of colonization areas can facilitate conservation planning.

2. Planning for reintroduction of gray wolves (Canis lupus) to the United States state of Colorado is underway. Assessing which occupancy sites minimize the likelihood of human-wolf conflict during dispersal events and seasonal movements is critical to the success of this initiative.

3. We used a spatial absorbing Markov chain (SAMC) framework, which extends random walk theory and probabilistically accounts for both movement behavior …

Development And Evaluation Of Prototype Toxicant-Delivery Bait Stations For The Control Of The Small Indian Mongoose, Carmen C. Antaky, Robert T. Sugihara, Israel L. Leinbach, Shane R. Siers, Emily W. Ruell, Steven C. Hess

United States Department of Agriculture Wildlife Services: Staff Publications

We conducted research to develop a safe and effective toxic bait to control the small Indian mongoose (Urva auropunctata), an invasive vertebrate predator impacting the survival of native species in Hawai‘i (United States) and in other parts of the world. A preserved fish-based bait product was found to be highly palatable to mongooses in cage trials and subsequent formulations with diphacinone (0.005%) showed promise as an efficacious toxic bait for mongooses. This product is intended for future use to control mongooses in conservation and urban areas, and as a biosecurity tool at ports of entry to address accidental …

Assessment Of Spilled Toxic Bait By Wild Pigs And Potential Risk To Non-Target Species, John C. Kinsey, Justin A. Foster, Nathan P. Snow, Jason D. Wishart, Linton D. Staples, Janis K. Bush, Kurt V. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Background

In 2018, a sodium nitrite (SN)-based toxic bait for invasive wild pigs (hereafter wild pigs; Sus scrofa), was evaluated to determine its effectiveness in reducing local wild pig populations in Texas. Localized population reductions of > 70% were achieved, but spillage of bait outside wild pig-specific feeders (bait stations) caused by feeding wild pigs resulted in the deaths of non-target animals. To evaluate risks to non-target animals, we tested whether bait presentation influenced the total amount of bait spilled by wild pigs and estimated the associated risk to non-target species.

Results

We found that bait spilled outside bait stations …

Population Density Of The Small Indian Mongoose (Urva Auropunctata) Across Multiple Habitat Types And Seasons In Puerto Rico, Are R. Berentsen, Caroline C. Sauvé, Mel J. Rivera-Rodriguez, Fabiola B. Torres-Toledo, Richard B. Chipman, Amy T. Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

The small Indian mongoose (Urva auropunctata) is a rabies reservoir on several Caribbean Islands including Puerto Rico. In the continental United States, oral rabies vaccination (ORV) has been used to control and locally eliminate rabies viruses targeting meso-carnivores including raccoons (Procyon lotor), grey foxes (Urocyon cinereoargenteus), and coyotes (Canis latrans), and has more recently been proposed to mitigate and control mongoose rabies in Puerto Rico. A fundamental understanding of the population density of the target species is an important factor in planning bait application rates prior to ORV operations. In Puerto Rico, …

Dna Metabarcoding Reveals Consumption Of Diverse Community Of Amphibians By Invasive Wild Pigs (Sus Scrofa) In The Southeastern United States, Vienna R. Canright, Antoniette J. Piaggio, Sarah M. Chinn, Rachael M. Giglio, Joseph M. Craine, James C. Beasley

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive wild pigs (Sus scrofa) are one of the most widespread, destructive vertebrate species globally. Their success can largely be attributed to their generalist diets, which are dominated by plant material but also include diverse animal taxa. Wild pigs are demonstrated nest predators of ground-nesting birds and reptiles, and likely pose a threat to amphibians given their extensive overlap in wetland use. DNA metabarcoding of fecal samples from 222 adult wild pigs culled monthly from 2017 to 2018 revealed a diverse diet dominated by plant material, with 166 plant genera from 56 families and 18 vertebrate species identified. …

Comparison Of Daily Activity Patterns Across Seasons Using Gps Telemetry And Camera Trap Data For A Widespread Mammal, David W. Wolfson, Peter E. Schlichting, Raoul K. Boughton, Ryan S. Miller, Kurt C. Vercauteren, Jesse S. Lewis

United States Department of Agriculture Wildlife Services: Staff Publications

Daily activity patterns of animals can be dynamic across seasons in response to changing environmental conditions. Daily activity, though, has rarely been evaluated in relation to multiple factors (for example, seasons, demographics, and data collection methods), which could be important for understanding what drives activity patterns. Here, we evaluated the daily activity patterns of a widespread invasive species, wild pigs (Sus scrofa), across two ecologically different study areas at Buck Island Ranch, Florida, and Tejon Ranch, California (United States), from 2015 to 2018. Using GPS telemetry data (62 individuals in Florida, 21 individuals in California) and detections from …

Are Rabid Raccoons (Procyon Lotor) Ready For The Rapture? Determining The Geographic Origin Of Rabies Virus-Infected Raccoons Using Radcapture And Microhaplotypes, Matthew W. Hopken, Antoinette J. Piaggio, Zaid Abdo, Richard B. Chipman, Clara P. Mankowski, Kathleen M. Nelson, Mikaela Samsel Hilton, Christine Thurber, Mirian T. N. Tsuchiya, Jesús E. Maldonado, Amy T. Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

North America is recognized for the exceptional richness of rabies virus (RV) wildlife reservoir species. Management of RV is accomplished through vaccination targeting mesocarnivore reservoir populations, such as the raccoon (Procyon lotor) in eastern North America. Raccoons are a common generalist species, and populations may reach high densities in developed areas, which can result in contact with humans and pets with potential exposures to the raccoon variant of RV throughout the eastern United States. Understanding the spatial movement of RV by raccoon populations is important for monitoring and refining strategies supporting the landscape-level control and local elimination of …

Home Range Overlap Between Small Indian Mongooses And Free Roaming Domestic Dogs In Puerto Rico: Implications For Rabies Management, Caroline C. Sauvé, Are R. Berentsen, Steven F. Llanos, Amy T. Gilbert, Patrick A. Leighton

United States Department of Agriculture Wildlife Services: Staff Publications

The small Indian mongoose (Urva auropunctata) is the primary terrestrial wildlife rabies reservoir on at least four Caribbean islands, including Puerto Rico. In Puerto Rico, mongooses represent a risk to public health, based on direct human exposure and indirectly through the transmission of rabies virus to domestic animals. To date, the fundamental ecological relationships of space use among mongooses and between mongooses and domestic animals remain poorly understood. This study is the first to report mongoose home range estimates based on GPS telemetry, as well as concurrent space use among mongooses and free roaming domestic dogs (FRDD; Canis …

Type And Frequency Of Wild Pig-Domestic Livestock Contacts And Operator Concern For Disease Spread, Sophie C. Mckee, Daniel F. Mooney, Ryan S. Miller

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) can levy substantial costs to domestic livestock operations and global supply chains due to disease introduction. Producers can take defensive action to avert these costs, but the factors influencing these decisions are not well understood. We examined survey data to characterize the type and frequency of contacts between wild pigs and domestic livestock and investigated the determinants of farm operator concern for disease introduction using an ordered logit model. We found that operators with livestock kept in buildings were more concerned about disease than those with livestock kept in fenced areas or that roam …

Turkey Vulture Survival Is Reduced In Areas Of Greater Road Density, Adrián Naveda-Rodríguez, Keith L. Bildstein, David R. Barber, Jean-François Therrien, Michael L. Avery, Bryan M. Kluever, Scott A. Rush, Francisco J. Vilella

United States Department of Agriculture Wildlife Services: Staff Publications

The demography of, and factors that influence these metrics, are largely unknown for most vultures in the Americas. Survivorship of turkey vultures (Cathartes aura) may be influenced by landscape heterogeneity and human disturbance. We quantified the effects of landscape composition (Shannon’s diversity index) and configuration (contagion, edge density, and largest patch index), and human disturbance (road density) on the annual and seasonal survival probabilities of the three North American breeding populations (western, central, and eastern) of turkey vultures that spend the nonbreeding season in the southeastern portion of the Nearctic and the northern Neotropics during a 17-year period. …

Hepatozoon Spp. Infection In Wild Canids In The Eastern United States, Eliza Baker, Alex Clemson, Debra Miller, Kayla Buck Garrett, Christopher A. Cleveland, Justin Brown, Kyle Van Why, Richard W. Gerhold Jr.

United States Department of Agriculture Wildlife Services: Staff Publications

Background Hepatozoon spp. are apicomplexan parasites known to cause musculoskeletal disease in a variety of animals. Two species are known to infect wild and domestic canids in the United States: Hepatozoon canis and H. americanum.

Methods In this study, blood, heart, and/or spleen samples were collected from 278 wild canids (180 coyotes, 93 red foxes, and 5 gray foxes) in the eastern US and tested via PCR for Hepatozoon. Histology slides of heart and skeletal muscle were assessed for Hepatozoon cysts and associated inflammation when fresh tissue was available (n = 96).

Results Hepatozoon spp. were …

A Next-Generation Sequencing Study Of Arthropods In The Diet Of Laysan Teal Anas Laysanensis, Wieteke A. Hothuijzen, Carmen C. Antaky, Elizabeth N. Flint, Jonathan H. Plissner, Coral A. Wolf, Holly P. Jones

United States Department of Agriculture Wildlife Services: Staff Publications

The critically endangered Laysan teal Anas laysanensis (known as koloa po¯haka in the Hawaiian language), in the northwestern Hawaiian Islands has wild populations on Kamole (Laysan Island), Kuaihelani (Midway Atoll NWR) and Ho¯laniku¯ (Kure Atoll). The Laysan teal face a new risk on Sand Island in Kuaihelani: non-target poisoning via a pending House Mouse Mus musculus eradication program. After mice were observed attacking and depredating Laysan albatross Phoebastria immutabilis (mo¯lı¯) in 2015, plans to eradicate the mice were developed to protect this seabird species. This approach, however, risks poisoning the Laysan teal. To reduce exposure, teal will be translocated during …

Raccoon Densities Across Four Land Cover Types In The Southeastern United States, Jocab E. Hill, James L. Helton, David A. Bernasconi, Wesley C. Dixon, Matt T. Hamilton, Richard B. Chipman, Amy T. Gilbert, James C. Beasley, Guha Dharmarajan, Olin E. Rhodes Jr.

United States Department of Agriculture Wildlife Services: Staff Publications

Raccoons (Procyon lotor) are the primary reservoir for rabies virus in eastern North America. Management of rabies in raccoons is achieved primarily with the use of oral rabies vaccination (ORV) and effective ORV bait densities are determined in part by the densities of raccoons. Decisions regarding ORV bait densities, however, are limited by an incomplete understanding of raccoon densities across the spectrum of landscapes they occupy. We carried out a markrecapture study of raccoons on the Savannah River Site in South Carolina, USA, from 2017–2019, to develop sex‐ and landscape‐specific raccoon density estimates across 4 rural land cover …

Differences In Drifting Invertebrate Communities Across Arctic Ecozones And The Influence On Potential Growth Of Grayling (Thymallus Arcticus), Charles Chanyi

Theses and Dissertations (Comprehensive)

Invertebrate drift is a key process that potentially affects multiple levels of food web organization within stream environments. However, our understanding of the mechanistic drivers of drift in high latitude streams and subsequent bottom-up control that drift may have on fish predators in these environments remains understudied. This project aimed to gain the baseline knowledge of how drift functions across two major high latitude ecozones, the boreal forest and tundra, and how those possible differences in drifting community characteristics may impact drift-feeding Arctic grayling (Thymallus arcticus). These objectives were accomplished by characterizing stream environments across both ecozones, sampling …

A Multi-Isotope Approach Reveals Seasonal Variation In The Reliance On Marine Resources, Production Of Metabolic Water, And Ingestion Of Seawater By Two Species Of Coastal Passerine To Maintain Water Balance, Lucas Navarrete, Nico Lübcker, Felipe Alvarez, Roberto Nespolo, Juan Carlos Sanchez-Hernandez, Karin Maldonado, Zachary D. Sharp, John P. Whiteman, Seth D. Newsome, Pablo Sabat

Biological Sciences Faculty Publications

Tracing how free-ranging organisms interact with their environment to maintain water balance is a difficult topic to study for logistical and methodological reasons. We use a novel combination of triple-oxygen stable isotope analyses of water extracted from plasma (δ¹⁶O, δ¹⁷O, δ¹⁸O) and bulk tissue carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes of feathers and blood to estimate the proportional contribution of marine resources, seawater, and metabolic water used by two species of unique songbirds (genus Cinclodes) to maintain their water balance in a seasonal coastal environment. We …

Estimating The Distribution Of Oryzomys Palustris, A Potential Key Host In Expanding Rickettsial Tick-Borne Disease Risk, Catherine A. Lippi, Samuel Canfield, Christina Espada, Holly D. Gaff, Sadie J. Ryan

Biological Sciences Faculty Publications

Increasingly, geographic approaches to assessing the risk of tick-borne diseases are being used to inform public health decision-making and surveillance efforts. The distributions of key tick species of medical importance are often modeled as a function of environmental factors, using niche modeling approaches to capture habitat suitability. However, this is often disconnected from the potential distribution of key host species, which may play an important role in the actual transmission cycle and risk potential in expanding tick-borne disease risk. Using species distribution modeling, we explore the potential geographic range of Oryzomys palustris, the marsh rice rat, which has been …

Use Of Amino Acid Isotope Analysis To Investigate Capital Versus Income Breeding Strategies In Migratory Avian Species, Nico Lübcker, John P. Whiteman, Oliver N. Shipley, Keith A. Hobson, Seth D. Newsome

Biological Sciences Faculty Publications

1. Income and capital breeding represent opposing ends of a continuum of reproductive strategies. Quantifying nutrient allocation to reproduction is challenging, but recent advances in compound-specific stable isotope analysis hold promise for tracing the source of individual compounds allocated to reproduction.

2. Here, we describe a novel approach of using measured carbon (δ13C) and nitrogen (δ15N) isotope values of individual amino acids (AAs) in pectoral muscle of egg-laying females and egg yolk as a useful tool to quantify the reliance on income versus capital breeding in migrating species. We used white-fronted (Anser albifrons frontalis), lesser snow (A. …

Hide And Seek: An Exploration Of Antipredator And Predator Avoidance Mechanisms In Orthopodomyia Signifera In Response To Predation From Toxorhynchites Rutilus, Nathaniel Dahlberg

Master's Theses

There have been many observations of larval Orthopodomyia signifera coexisting with the predator Toxorhynchites rutilus. There are three hypotheses that could explain how Or. signifera resists predation from Tx. rutilus. The first hypothesis states that larvae adapt behavioral changes that limit predation. The second hypothesis states thoracic setae serve as a physical defense that prevents Tx. rutilus from grasping Or. signifera. The third hypothesis states Or. signifera possess a chemical defense indicated by aposematic coloration. To test the first hypothesis larval Or. signifera were exposed to conspecific and heterospecific predation cues and their behavior was observed. Both cues …

Effect Of Clostridium Butyricum Supplementation On Production Performance, Egg Quality, Gut Microflora, And Intestinal Morphology Of Laying Hens In The Late Phase Of Production, Phuong Truc Le Ho

Chulalongkorn University Theses and Dissertations (Chula ETD)

This experiment was conducted to evaluate the effects of Clostridium butyricum supplementation on improvement of production performance and egg quality by stimulating the intestinal absorptive function and altering the cecal microbial composition. A total of 216 Hy-Line brown laying hens at 66 weeks of age were allocated randomly into 3 treatments with 6 replicates of 12 hens in a completely randomized design. The dietary treatments included a control group (CT) with a corn-soy basal diet, and the other treatments comprised basal diets supplemented with 250g/ton (CB1) and 500g/ton (CB2) of feed containing C. butyricum strain MIYAIRI 588. The concentration of …