Population Biology Commons^™

False-Positive Detections In Avian Auditory Surveys: Effects Of Song Number And Directionality In A Calibration-Based Immersive Sound Environment, Katia Elena Chavez

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Detection-based surveys are widely conducted to monitor wildlife populations and provide data for estimating density and abundance. Avian count surveys are especially common because birds respond quickly to habitat degradation and restoration, making them effective indicator species. However, these detection-based surveys rely heavily on human observers and are prone to errors. If left unaddressed, these errors can bias estimates of species occurrence, and abundance, leading to misleading ecological inferences and management decisions. False-positive errors have received limited attention, in part because they are difficult to identify without independent confirmation of true species. To investigate false-positive rates in a controlled setting, …

Long-Term Banding And Encounter Patterns Of Cinnamon Teal Banded In Utah (1960-2025), Gracie A. Henrie

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Utah is a valuable breeding and nesting ground for a number of waterfowl species, largely because of the Great Salt Lake, which supports over 400,000 acres of wetland habitat (Ducks Unlimited, n.d.). The Utah Division of Wildlife Resources manages 24 wildlife management areas (WMAs) with the purpose of creating high quality waterfowl habitat in these wetlands that can be enjoyed by hunters, recreators, and birds alike (Wildlife/Waterfowl Management Areas (WMAs), 2025). Effective management is supported with an understanding of the movement and demographic patterns of the waterfowl species the WMAs are designed to support. Bird banding is one tool managers …

Exploring The Reproductive Phenology Of Feral Horses In North America, Mattie Budine

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Feral horses (Equus ferus caballus) are a prolific species in western North America. Due to their life history traits and history of domestication, they have a longer foaling period compared to native ungulates, such as elk (Cervus canadensis) and mule deer (Odocoileus hemionus). I examined the observed foaling seasons of different regional herds throughout North America to identify if foaling seasons are uniform across latitudes or if they present a latitudinal shift similar to ungulates. My dataset (n=523 foals) consisted of various research studies and unpublished observations of different feral horse herds throughout North America. The results are graphs comparing …

Better Together: Leveraging Existing Research To Evaluate Population Trends, Habitat Selection, And Species Interactions Of Mesocarnivores, Jordan Lee Heiman

Graduate Student Theses, Dissertations, & Professional Papers

Whether from human impacts, climate change, or extreme fires, landscapes around the world are rapidly changing (Foley et al. 2005, Grimm et al. 2008, Bowman et al. 2020). As these landscapes change, it is clear that many ecosystems and species are being negatively affected (Laliberte and Ripple 2004, Butchart et al. 2010, Freeman et al. 2018, Li et al. 2022). With an expanding number of species facing extinction risks, it is critical for agencies to know when and where to focus their limited resources and conservation efforts (Martin et al. 2012, Auerbach et al. 2014, Bal et al. 2018). To …

Binoculars To Bytes: Development And Field Validation Of An Ai-Driven System For Avian Monitoring, Christian J. Dupree

Graduate Student Theses, Dissertations, & Professional Papers

Autonomous camera-trap arrays coupled with artificial-intelligence (AI) vision can lift bird monitoring beyond the spatial, temporal, and labor limits of traditional field surveys. We present Binoculars to Bytes (B2B), an open-source pipeline that turns 180–360° time-lapse imagery into analysis-ready avian data. At Freezout Lake Wildlife Management Area (Montana, USA) the system ran four-hour morning deployments during spring and fall migrations (2023–2024). A YOLO-NAS detector, incrementally refined with a “Specialized Localized Iterative Model” workflow, quadrupled local accuracy and, after confidence-based species-binning, cut false-positive rates in half. Daily AI species lists were benchmarked against contemporaneous eBird citizen-science checklists and recovered ≥ …

Estimation Of Probability Of Habitat Use Of Roosevelt Elk On The Olympic Peninsula, Vincent Michael Gugliotti

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Estimating the probability of habitat use for a particular species is crucial to the direct management and conservation of that species. Without knowledge of habitat preferences, managers cannot effectively focus efforts on vital resources or landscape types. However, modelling probability of habitat use can be done in several ways which leaves room for variation and uncertainty in the estimates produced by each method. This study is an examination of the variation between two estimates of probability of habitat use while focusing on a particular subspecies of elk that inhabits a unique ecosystem relative to other elk subspecies. I modeled elk …

Moose Abundance And Calf:Cow Ratios On The Blackfeet Indian Reservation And Glacier National Park, Landon Joel Magee

Graduate Student Theses, Dissertations, & Professional Papers

Many moose (Alces alces; Sikihtsisoo) populations across North America, especially along their southern range, are declining due to factors such as climate change, parasites and disease, predation, habitat loss and degradation, and overharvest. These declines highlight broader ecological concerns, as moose play a critical role as prey within their ecosystems. Despite their importance, data on crucial demographic parameters like abundance and age ratios are sparse for moose, complicating management efforts. Conventional monitoring methods, including radio-collaring, harvest data, public surveys, and aerial surveys, face significant logistical and financial challenges, and often fail to provide a comprehensive understanding of …

Better Understanding The Barred Owl, Adam Lee Potts

Graduate Student Theses, Dissertations, & Professional Papers

This thesis research presents an analysis of barred owl nest site selection in an understudied region of their expanded range. The barred owl has dramatically expanded its range westwards over the last 150 years, prompting multiple conflicting reinterpretations of their species account. Hypotheses of range expansion are reviewed to provide context for this study’s research. This study gathers empirical data on nest site selection in the mixed conifer forests of Montana’s Seeley-Swan and Mission Valleys. Eight barred owl nests were located following extensive territory surveys. Field measurements of tree height and diameter using USFS Forest Inventory and Analysis (FIA) plot …

Individual And Population Responses To Hydrologic Variability In A Headwater Stream Salamander, Madaline Cochrane

Graduate Student Theses, Dissertations, & Professional Papers

Understanding how organisms respond to environmental variability is a central goal in ecology – a goal made even more pressing by the herculean challenge global climate change presents to all organisms. Climate change is increasing the frequency and intensity of floods and droughts, which will likely have disproportionate effects on freshwater organisms. Many stream-associated species have multi-stage life histories. However, we lack an empirical understanding of life history and movement responses of these organisms to hydrologic disturbances, and how these responses may influence demographic rates. In my dissertation, I used a combination of growth, developmental, movement, and demographic data to …

Predicting Mountain Lion Resource Selection And Abundance In North America, William Connor O'Malley

Graduate Student Theses, Dissertations, & Professional Papers

The relationship between habitat quality and density is well documented in lower trophic levels but to what extent it can be extended to higher trophic levels is unknown. I tested the relationship between habitat quality, home-range size and density using a wide-ranging, well-studied, top carnivore, the mountain lion (Puma concolor). First, I created a second-order resource selection function (RSF) for mountain lions in their current North American range using GPS collar data from 476 individuals in 20 study sites and remotely-sensed landscape data. I used the RSF and home range estimates derived from collared animals to quantify mountain …

Understanding Caribou Population Cycles, Jack R. St. John

Undergraduate Theses, Professional Papers, and Capstone Artifacts

The complex population dynamics of caribou (Rangifer tarandus) were studied to determine the patterns of their population cycles and the processes driving them. It is well established, via previous archaeological research and Indigenous knowledge, that large migrating caribou herds found in and around the tundra at northern latitudes experience population boom and busts roughly every several decades. However, the processes driving the dynamics of these cycles are relatively unknown, which makes managing caribou herds for recreational and subsistence harvests difficult. It has been hypothesized that a combination of intrinsic and extrinsic factors shape these cycles, with density-dependence, predation, …

Evaluating The Use Of Camera Traps To Monitor Populations Of Ungulate Prey In The Russian Far East, Scott Johnston Waller

Graduate Student Theses, Dissertations, & Professional Papers

Efforts to recover endangered carnivore populations are often limited by insufficient populations of prey. When recovering prey populations, estimates of population density are invaluable metrics to monitor recovery efforts. In Russia, wildlife managers use the Formozov-Malyushev-Pereleshin (FMP) snow tracking method to estimate densities of ungulate prey of the Amur tiger (Panthera tigris). Yet, increasing variability in snow conditions and other challenges have limited its reliability. Camera traps offer a promising alternative approach since managers already use cameras to monitor tigers. However, the assumptions and study design necessary to implement capture-recapture models for tigers are different from those needed …

A Reintroduction Retrospective: Comparative Fisher (Pekania Pennanti) Survival And Prey Habitat Use In The Cascade Mountains Of Washington State, Tanner S.T. Humphries

Graduate Student Theses, Dissertations, & Professional Papers

Increasing human impacts on biodiversity highlight the global need for ecological restoration. For many wildlife species, reintroduction is necessary to re-establish populations in parts of their historic range where they have been extirpated. Reintroduction efforts are commonly used to help restore ecosystem integrity, but are often expensive, time consuming, and unsuccessful at generating self-sustaining populations. Thus, a more complete understanding of the factors affecting restoration success is important for ensuring successful outcomes and responsible stewardship. Fishers (Pekania pennanti) are one of the most commonly reintroduced carnivores in North America, but the success of such efforts is highly variable, …

Finding Fishers: Determining The Distribution Of A Rare Forest Mesocarnivore In The Northern Rocky Mountains, Jessica M. Krohner

Graduate Student Theses, Dissertations, & Professional Papers

The Northern Rocky Mountain fisher population (Pekania pennanti), is classified as a Species of Greatest Conservation Need and is of special concern to state, federal, and tribal entities. In this thesis, we present methods to effectively survey fishers across the northern Rockies of Idaho and Montana, and provide estimates of fisher distribution at a population range-wide scale through occupancy analyses. We also assess factors that influence fisher occurrence through covariate analyses and identify core fisher habitat in the northern Rockies through spatial occupancy modeling. By sampling broadly across the landscape, we provide baseline distributional data for comparison against …

Golden Eagle Resource Selection And Environmental Drivers Of Reproduction In The Northern Range Of Yellowstone National Park, David Brown Haines

Graduate Student Theses, Dissertations, & Professional Papers

In the United States (US), National Parks are considered the “crown jewels” of protected lands. However, the importance of National Parks to wildlife populations and the species that inhabit them is not often quantified, thus, requiring a better understanding of National Parks as a conservation tool. Golden eagles (Aquila chrysaetos) are a North American species of conservation concern and territories in the northern range of Yellowstone National Park (YNP) are relatively dense. However, average reproductive rates over the past ten years (2011-2020) have been low (productivity = 0.34, nest success = 28%). The contrast of high density and …

Comparing Fence Modeling And Mapping Approaches To Support Wildlife Management And Research In Southwest Montana, Simon Albert Buzzard

Graduate Student Theses, Dissertations, & Professional Papers

Fences pose significant challenges to wildlife movement, but their effects are difficult to quantify because fence location and fence type data are lacking on a global scale. We developed a fence location and density model in southwest Montana, USA to provide data to researchers and managers, and test whether previous models could be applied to a new region and retain suitable levels of statistical accuracy. Our model used local expert opinion to inform how road, land cover, and ownership spatial layers interacted to predict fence locations. We validated the model against fence data collected on random 3.2 km road transects …

Resource Selection And Calving Success Of Moose In Colorado, Forest P. Hayes

Graduate Student Theses, Dissertations, & Professional Papers

Across much of North America, moose populations (Alces alces) are declining due to disease, predation, climate, and anthropogenic pressures. Despite this, populations of moose in Colorado have continued to grow. Studying successful (i.e., persistent or growing) populations of moose can facilitate the continued conservation of the species by identifying habitat features critical for moose persistence.

First, I evaluated calving success of moose in Colorado and the impact of willow habitat quality and nutrition. I then estimated the probability of female moose having a calf using repeated observations in a Bayesian occupancy model. I assigned values for dry matter …

Methods For Estimating Mountain Goat Occupancy And Abundance, Molly Mcdevitt

Graduate Student Theses, Dissertations, & Professional Papers

Abundance and occupancy are two parameters of central interest to the field of ecology. Furthermore, accurate (both precise and unbiased) estimates are key pieces to the puzzle of effective wildlife management decision-making. While there exist a variety of sampling techniques and statistical models for effectively estimating population parameters for frequently encountered and large mammals, methods for sampling unmarked and rare species are few and far between. The first step to acquiring usable parameter estimates is through the use of sampling theory and incorporation of probabilistic sampling designs to collect count-data and occurrence-data. Often, it is assumed that probabilistic sampling designs …

Population And Breeding Ecology Of Sagebrush Steppe Songbirds, Kayla Ann Ruth

Graduate Student Theses, Dissertations, & Professional Papers

Sagebrush steppe is one of the most threatened ecosystems in North America. Domestic livestock grazing is the dominant land use of sagebrush steppe across the west. Rest-rotation grazing systems can be a conservation management tool, most recently, by the Natural Resource Conservation Service - Sage Grouse Initiative (SGI). The goal of SGI is to encourage private landowners to use a livestock grazing regime that maintains or improves habitat for greater sage-grouse (Centrocercus urophasianus), as well as improve rangeland productivity. Songbirds are biological indicators that can assess the health of sagebrush steppe. Avian adult density estimates are often used …

Estimating Juvenile Recruitment Of Elk In An Occupancy Modeling Framework, Mateen A. Hessami

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Juvenile recruitment is a key parameter in understanding ungulate population dynamics. Traditional methods in population composition surveys, such as estimating young: adult-female ratio’s, can be precluded by cost, safety, and feasibility. The use of remote cameras provides a potentially cutting-edge tool to apply to wildlife population estimation techniques. While the prevalence of remote cameras in ungulate studies has increased, few studies have used cameras to estimate vital rates, such as recruitment or survival. Here, we tested the potential of remote cameras to estimate calf: cow ratios and calf survival of elk (Cervus elaphus) using the Royle-Nichols (2003) occupancy …

Assessing The Robustness Of Time-To-Event Abundance Estimation, Kenneth E. Loonam

Graduate Student Theses, Dissertations, & Professional Papers

Abundance estimates can inform management policies and are used to address a variety of wildlife research questions, but reliable estimates of abundance can be difficult and expensive to obtain. For low-density, difficult to detect species, such as cougars (Puma concolor), the costs and intensive field effort required to estimate abundance can make working at broad spatial and temporal scales impractical. Remote cameras have proven effective in detecting these species, but the widely applied methods of estimating abundance from remote cameras rely on some portion of the population being marked or uniquely identifiable, limiting their utility to populations with naturally occurring …

Camera Traps In Wildlife Research: Through My Lens, Bryson P. Allen

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Wildlife species can be difficult to study because they can have very large ranges and can be wary of observers. Researchers have been using camera traps in recent decades as a way to study wildlife behavior and population metrics. Here I explore the history of these tools in wildlife biology, their possible applications, and limitations.

Life On The Edge: Risk Of Predation Drives Selection Of Habitat And Survival Of Neonates In Endangered Sierra Nevada Bighorn Sheep, Shannon Forshee

Graduate Student Theses, Dissertations, & Professional Papers

Long-term viability of endangered populations requires development of effective management strategies that target the population vital rate with the highest potential to influence population trajectories. When adult survival is high and stable, juvenile recruitment is the vital rate with the greatest potential to improve population trajectories. For my thesis I examined how lactating Sierra Nevada Bighorn sheep (Ovis Canadensis sierra) balance forage and predation risk during the neonatal period. I first identified resource selection strategies employed by lactating females to promote survival of neonates and then determined the primary factors affecting survival of neonates. I found lactating females selected for …

Quantifying False Positives In Avian Survey Data, Kaitlyn M. Strickfaden

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Imperfect detection is a known issue when conducting count-based surveys in wildlife studies. False positive detections, observed occurrences of individuals that truly are not present, are often assumed to not occur. This assumption can bias detection rates and create misleading results when calculating population estimates. Survey methods such as the dependent double-observer method are suggested to reduce the occurrence of false positives (Nichols et al. 2000). My study quantified and compared rates of false positives in a single-observer method and a dependent double-observer method using computer-generated auditory surveys. I categorized volunteer observers as either inexperienced or experienced and asked them …

Lewis’S Woodpecker Nest Success And Habitat Selection In Cottonwood Floodplain Versus Burned Conifer Forests, William M. Blake

Graduate Student Theses, Dissertations, & Professional Papers

Breeding habitat selection influences reproductive outcomes. Habitat selection may be adaptive and benefit populations, but it can also be maladaptive with negative consequences for populations. Understanding habitat selection and its influence on reproductive success, especially in species of concern, is critical for effective management. Lewis’s Woodpecker (Melanerpes lewis) is a Species of Concern that has experienced national population declines. We studied its abundance and reproductive success in two commonly selected breeding forest types (i.e., cottonwood floodplain and mixed-conifer burned), and nest-site characteristics (nest availability, food availability, and vegetation attributes) that have the potential to yield strong differences in …

Harvest And Persistence Of Wolf Populations: Variable Effects Of Harvest On Wolf Packs In The Rocky Mountains, Sarah B. Bassing

Graduate Student Theses, Dissertations, & Professional Papers

Pubic harvest is a common method used to manage populations of wolves (Canis lupus) in North America. Although wolves appear resilient to the effects of harvest management the influences on demography and pack stability are uncertain. Packs generally drive population dynamics for wolves; thus, we were interested in how harvested populations were maintained and how harvest influenced the abundance and distribution of packs. We used noninvasive genetic data collected in Idaho, USA (2008–2014) and Alberta, Canada (2012–2014) to test whether immigration compensated for harvest mortality and helped maintain population densities. We further fit occupancy models to detection data …

Influence Of Fine Sediment On Arctic Grayling (Thymallus Arcticus) Egg Survival And Spawning Habitat Suitability, Ian R. Anderson

Undergraduate Theses, Professional Papers, and Capstone Artifacts

The Arctic grayling (Thymallus arcticus) is a freshwater salmonid that is found in clear, cold waters throughout the northern regions of North America. Arctic grayling are still widespread in Alaska and Canada but have declined substantially in their two historic, disjunct southern populations in the contiguous United States. One of these populations was found in the AuSable River in Michigan and went extinct in the mid-1900s (Vincent 1962) while the other, found in the Upper Missouri River drainage in Montana, now inhabits a small portion of its historical range (Nelson 1954). Currently, only two native populations of Arctic …

Examining Temporal Sample Scale And Model Choice With Spatial Capture-Recapture Models In The Common Leopard Panthera Pardus, Joshua F. Goldberg, Tshering Tempa, Nawang Norbu, Mark Hebblewhite, L. Scott Mills, Tshewang R. Wangchuk, Paul Lukacs

Wildlife Biology Faculty Publications

Many large carnivores occupy a wide geographic distribution, and face treats from habitat loss and fragmentation, poaching, prey depletion, and human wildlife-conflicts. Conservation requires robust techniques for estimating population densities and trends, but the elusive nature and low densities of many large carnivores make them difficult to detect. Spatial capture-recapture (SCR) models provide a means for handling imperfect detectability, while linking population estimates to individual movement patterns to provide more accurate estimates than standard approaches. Within this framework, we investigate the effect of different sample interval lengths on density estimates, using simulations and a common leopard (Panthera pardus) …

Integrating Resource Selection Into Spatial Capture-Recapture Models For Large Carnivores, K. M. Proffitt, Joshua F. Goldberg, Mark Hebblewhite, R. Russell, B. S. Jimenez, H. S. Robinson, K. Pilgrim, M. K. Schwartz

Wildlife Biology Faculty Publications

Wildlife managers need reliable methods to estimate large carnivore densities and population trends; yet large carnivores are elusive, difficult to detect, and occur at low densities making traditional approaches intractable. Recent advances in spatial capture-recapture (SCR) models have provided new approaches for monitoring trends in wildlife abundance and these methods are particularly applicable to large carnivores. We applied SCR models in a Bayesian framework to estimate mountain lion densities in the Bitterroot Mountains of west central Montana. We incorporate an existing resource selection function (RSF) as a density co-variate to account for heterogeneity in habitat use across the study area …

Abundance, Density, And Opinions About Columbian Black-Tailed Deer, Whidbey Island, Washington, Robert P. Wingard

Graduate Student Theses, Dissertations, & Professional Papers

Obtaining reliable knowledge is the first step towards properly managing wildlife species. Columbian black-tailed deer (Odocoileus hemionus columbianus) on Whidbey Island, Washington have not been the subject of study, and little is known about the population, or the opinion of resident’s of Whidbey Island towards the deer population. However, wildlife managers suggest deer on the island may be overabundant or over social carrying capacity. Given the lack of empirical knowledge about the deer population or human opinions towards deer on Whidbey Island, I designed research to determine the abundance and density of Columbian black-tailed deer on Whidbey Island, …