Areas Of Montana Research Articles

Establishing an indoor agriculture system at a rural Montana PreK‐12 school creates hands‐on experiences for college seniors studying horticulture

AbstractIn 2022, seniors studying horticulture at Montana State University (MSU; Bozeman, MT) had the opportunity to participate in a unique community‐based learning project in collaboration with the newly built PreK‐12 public school in the rural town of Winifred, MT, to establish the greenhouse infrastructure to be used in curriculum at the school. The new greenhouse facility presented an opportunity for Winifred students to not only gain experience growing vegetables, but also to provide a source of fresh vegetables for school lunches and for community members. This course presented two unique opportunities for the MSU horticulture students: (1) to experience problem‐solving horticultural challenges through designing and troubleshooting the setup of the cropping systems for the greenhouse and (2) to participate in a course with a real‐world impact on improving food security in rural areas of Montana. Over the course of the semester, the MSU students successfully established the infrastructure for the Winifred School greenhouse, which has continued to be integrated into the curriculum as well as providing fresh produce for students and community members. By the end of the course, MSU students demonstrated program learning outcomes including demonstrating the content knowledge and skills necessary to function successfully in a horticultural career and being able to identify and analyze plant growth problems and develop solutions or strategies to solve those problems.

Recent Developments in Helium Exploitation in southern Saskatchewan and adjacent areas of Montana and Alberta

The following is a survey of a re-emerging helium exploration and production area located at the northwest rim of the Williston Basin located in southwest Saskatchewan, southeastern Alberta, and north central Montana. The Williston Basin is one of the two major sub-basins of the Western Canadian Sedimentary Basin; the other being the Alberta Basin foreland basin, east of the Cordillera. From a slow 2016 start, 21st century helium production from the area already exceeds the total from area’s 1960s and 70s production heyday. As mid-continent legacy helium storage and production decline, the importance of this area’s net-zero helium production can only grow.

Assessment of L-band InSAR snow estimation techniques over a shallow, heterogeneous prairie snowpack

Snow water equivalent (SWE) is a critical input for weather, climate, and water resource management models at local to global scales. Despite its importance, global SWE measurements that are accurate, consistent, and at sufficiently high spatiotemporal resolutions are not currently available. L-band interferometric synthetic aperture radar (InSAR) techniques have been used to measure SWE at local to regional scales, and two upcoming L-band SAR satellite missions have renewed interest in these techniques to provide regular SWE measurements at the global scale. However, previous research demonstrating the capabilities of L-band InSAR-SWE measurement has been limited to mountain or tundra snowpack regimes. Here we examine the feasibility of applying the same techniques over a prairie snowpack, which are typically characterized by shallow snow depths (mean snow depth of 0.22 m in this study), exposed agricultural vegetation, and high spatial variability over short distances. Our study area in central Montana, USA (47.060, -109.951) was a validation site for NASA SnowEx 2021, as part of the UAVSAR snow timeseries. Airborne L-band SAR imagery was acquired by the UAVSAR platform while concurrent snow measurements were collected using uncrewed aerial vehicle (UAV)-based LiDAR, UAV-based photogrammetry, and ground-based manual techniques. This validation dataset enables an investigation of the effects of sub-pixel snow cover heterogeneity and exposed agricultural vegetation stubble on SAR data and the resulting SWE estimations. Results based on repeated application of the Kolmogorov–Smirnov test show that UAVSAR VV phase change is sensitive to differences in snow cover but relatively unaffected by differences in agricultural stubble height. However, we did not find similarly definitive results when we used the same phase change data to estimate SWE. Although broad spatial patterns were similar in both LiDAR-derived and InSAR-derived SWE estimates, considerable differences in the two estimates were apparent in areas with large sub-pixel snow depth variability. Our results indicate that additional work is necessary to derive accurate SWE estimates in prairie environments. Regular measurements from L-band SAR satellites will provide an excellent opportunity to refine InSAR-based snow estimation techniques over shallow, heterogeneous snowpacks.

Using Structure Location Data to Map the Wildland–Urban Interface in Montana, USA

The increasing wildfire activity and rapid population growth in the wildland–urban interface (WUI) have made more Americans exposed to wildfire risk. WUI mapping plays a significant role in wildfire management. This study used the Microsoft building footprint (MBF) and the Montana address/structure framework datasets to map the WUI in Montana. A systematic comparison of the following three types of WUI was performed: the WUI maps derived from the Montana address/structure framework dataset (WUI-P), the WUI maps derived from the MBF dataset (WUI-S), and the Radeloff WUI map derived from census data (WUI-Z). The results show that WUI-S and WUI-P are greater than WUI-Z in the WUI area. Moreover, WUI-S has more WUI area than WUI-P due to the inclusion of all structures rather than just address points. Spatial analysis revealed clusters of high percentage WUI area in western Montana and low percentage WUI area in eastern Montana, which is likely related to a combination of factors including topography and population density. A web GIS application was also developed to facilitate the dissemination of the resulting WUI maps and allow visual comparison between the three WUI types. This study demonstrated that the MBF can be a useful resource for mapping the WUI and could be used in place of a national address point dataset.

Hayden's Landscapes Revisited: The Drawings of the Great Colorado Survey

Hayden's Landscapes Revisited: The Drawings of the Great Colorado Survey

Reconnecting stranded public lands is a win-win for conservation and people

The spatial distribution of many public lands in the western U.S. is an artifact of 19th century land-disposal policies. While this legacy is sometimes an impediment to conservation, it may also provide novel opportunities to spatially reorganize public conservation lands within realistic budget constraints. Here we seek to understand the conservation potential of strategically rearranging inaccessible (“stranded”) public land in Montana, US. We use conservation reserve network design and consider coarse- and fine-filter conservation features—land cover types and predicted habitat for 12 umbrella species, respectively—and incorporate habitat connectivity corridors into one reserve design scenario. All conservation reserve network designs are constrained by a budget equal to the current value of stranded public land parcels and seek to meet or exceed the extent of conservation currently provided by stranded parcels with respect to land cover type and predicted species habitat. We find that each conservation reserve simulation expands the total protected area in Montana within the realistic budget constraint. Two maximum coverage scenarios, which exhaust the budget, result in reserve designs that substantially exceed coarse- and fine-filter conservation targets. All reserve designs provide landscape connectivity benefits. Our results illustrate notable and practical opportunities to develop conservation reserve networks in the western US that account for landscape connectivity and that benefit both private landowners and biodiversity conservation efforts through land trades and acquisitions.

Trade-offs in forest disturbance management for plant communities and ungulates

Land and wildlife managers use disturbance to reset forests to earlier successional stages and improve the quality and quantity of forage available to ungulates. However, management of vegetation communities to increase forage nutrition has additional implications for other non-forage vegetation. To evaluate responses of vegetation to management of fire and timber harvest, we measured and modeled 3 metrics of vegetative response in 3 forested areas in Montana, USA during 2017–2019: forage nutrition for mule deer (Odocoileus hemionus), invasive species biomass, and floristic quality, a measure of plant communities’ tolerance of disturbances and fidelity to particular environments using native species conservatism scores. We found differences in all 3 metrics of plant responses that were specific to disturbance type and study area, and associations between disturbance and vegetation outcomes that were both desirable and undesirable. Generally, deer forage nutrition and invasive species biomass both increased in disturbed areas, whereas floristic quality increased with disturbance in 2 study areas but decreased in the third. Biomass of particular invasive species varied according to both study area and disturbance type. Lastly, we used decision analysis to illustrate trade-offs and overall support for different management actions while also accounting for underlying differences among study areas. For example, management actions with the greatest increase in mule deer forage nutrition tended to also increase invasive species biomass. Compared to other management actions, low-severity harvest scored highly in 2 study areas due to its association with increased forage nutrition while also limiting invasive species biomass and maintaining floristic quality. However, different weighting schemes according to different management priorities among management outcomes alter the relative ranking of actions. Our data show area-specific trade-offs in vegetation outcomes that result from disturbance management, which can be combined with decision analysis to help managers balance objectives and compare potential management actions.

Demographic differences in hiker cellular technology use in backcountry areas in Montana’s Custer Gallatin National Forest

Technology remains an important part of outdoor recreation, ranging from the introduction of lighter materials in gear to new gadgets that improve the outdoor experience. Recently, advances in cellular technology and mobile devices have presented new opportunities for using mobile technology in backcountry areas. Applications ranging from public lands apps to GPS apps are a now a common find in outdoor recreation areas. Use of mobile technologies, such as cellular phones, can differ by demographic variables such as sex, age, and income. This presents a valuable opportunity to explore how and why demographics may shape the use of cellular devices while in the backcountry. This study examines technology use among hikers in Montana’s Custer Gallatin National Forest. Using data from an online survey, the researchers explored the importance of eight different uses of cellular technology while in the backcountry and analyzed how these responses vary by sex, age, income, and education categories. The results indicate cellular technology plays a varied, albeit often neutral or even unimportant, role in backcountry outdoor recreation situations. Notably, these experiences do vary by age, education, and income categories but, surprisingly, not sex. Important outcomes include new understanding of hiker use of cellular devices as cameras, wayfinding devices, and for information gathering while in the backcountry.

Potential geographic distribution of Ixodes cookei, the vector of Powassan virus.

Ixodes cookei Packard, the groundhog tick or woodchuck tick, is the main known vector of Powassan virus (POWV) disease in North America and an ectoparasite that infests diverse small- and mid-size mammals for blood meals to complete its life stages. Since I. cookei spends much of its life cycle off the host and needs hosts for a blood meal in order to pass to the next life stage, it is susceptible to changes in environmental conditions. We used a maximum-entropy approach to ecological niche modeling that incorporates detailed model-selection routes to link occurrence data to climatic variables to assess the potential geographic distribution of I. cookei under current and likely future climate conditions. Our models identified suitable areas in the eastern United States, from Tennessee and North Carolina north to southern Canada, including Nova Scotia, New Brunswick, eastern Newfoundland and Labrador, southern Quebec, and Ontario; suitable areas were also in western states, including Washington and Oregon and restricted areas of northern Idaho, northwestern Montana, and adjacent British Columbia, in Canada. This study produces the first maps of the potential geographic distribution of I. cookei. Documented POWV cases overlapped with suitable areas in the northeastern states; however, the presence of this disease in areas classified by our models as not suitable by our models but with POWV cases (Minnesota and North Dakota) requires more study.

521 Late-Breaking: Oral Mineral Drench to Reduce Morbidity and Increace Performance on Remore Summer Pastures

Abstract Economic losses due to morbidity and mortality associated with bovine respiratory disease (BRD), foot rot, pinkeye, and other health issues in yearling beef cattle are consistently over $2 billion annually. This trial was designed to test the hypothesis that yearling beef cattle individually treated with an oral micromineral drench would be associated with decreased BRD, foot rot, pinkeye, and other issues in the first 60 days with improved weight gains while grazing remote summer pastures. This trial utilized 1150 head of steers, spayed heifers, and intact heifers in areas of Idaho and Montana. Trial cattle had unknown background and nutritional history, with no metaphylaxis treatment upon arrival. Treatment data for BRD, pinkeye, and foot rot, and other abnormalities showed decreased morbidity (from 37.5–61%) in different groups P < 0.234 during the first 60 days of the trial compared to the untreated cattle. Weight gains on treatment steers showed an increase 0f 18.89 lbs. in group 2 and 12.34 lbs. in group 3 (salt only) in 100 days grazing in the treatment cattle compared to the controls. The bred heifer group 1 showed showed slight weight gains of 1% and an increase pregnancy rate of 2% compared to the controls after 100 days grazing. Further trials need to be completed to determine the desired dosage using an oral mineral drench on yearling beef cattle with unknown vaccination and nutritional history.

Elk Responses to Management Hunting and Hazing

ABSTRACTHuman‐wildlife conflicts are widespread around the world and result in property damage, disease spillover, financial loss, and decreased tolerance of wildlife. Increasing elk (Cervus canadensis) populations and land‐use changes in the western United States are challenging resource managers tasked with managing conflict. Lethal and non‐lethal management actions are commonly used to remove elk from conflict zones where they are not desired. We used radio‐collar location data collected from female elk in 2 study areas in Montana, USA, from 2017–2020 to evaluate population‐ and individual‐level responses to management actions (i.e., hunting, hazing) and environmental factors (i.e., weather, season, time of day). First, we used a generalized linear model with a logit link to evaluate the effects of hunting, hazing, time period, seasonality, and weather on the proportion of collared elk that used a conflict zone. Second, we used an ordinary linear model to assess the influence of hunting, hazing, seasonality, and weather on the duration of time that individual elk remained away from conflict zones. The proportion of elk using conflict zones was reduced by hunting, modestly reduced by hazing and increasing snowpack for 1 study area, increased at night, and decreased by a seasonal trend across months. The time individual elk remained away from conflict zones increased with the number of hazing events that occurred during an event and showed a modest seasonal trend increasing across months. For 1 study area, time away increased with the number of hunting days during an event and increasing snowpack, but the increase was biologically trivial. Our results indicate mixed responses of elk to hunting and hazing actions and provide evidence that management actions can influence elk use of conflict areas. Agencies trying to reduce conflicts may want to consider a combination of hunting and hazing, while accounting for site‐specific characteristics to keep elk away from conflict zones. © 2021 The Wildlife Society.

Analyzing sources of uncertainty in terrestrial organic carbon isotope data: A case study across the K-Pg boundary in Montana, USA

The Cretaceous-Paleogene boundary (KPB) in the Hell Creek area of Montana is recognized in several places by an iridium anomaly, which is typically identified at or very near the lithological contact between the Hell Creek Formation and the Tullock Member of the Fort Union Formation. Previous work in the area has argued that organic carbon isotope (δ13Corg) excursions can be used for chemostratigraphic correlation within these continental depositional environments, most importantly for the identification of the KPB where impact evidence is unavailable. However, it is unclear how modern surficial weathering affects δ13Corg values, particularly in terrestrial depositional settings, and whether standard sampling methods are sufficient to obtain unaltered rock material. We tested the fidelity of the terrestrial δ13Corg record with respect to surficial alteration and contamination through investigation of different field sampling techniques, including hand trenches, a backhoe-excavated trench, and sediment coring. We find that δ13Corg values in hand and backhoe trenched sections are more positive than δ13Corg values in cored sections, implying that modern surficial alteration affects δ13Corg values but not overall trends. A negative δ13Corg excursion associated with the KPB is present in most sections we analyzed, but it does not appear to be unique within our sections. The KPB excursion occurs within a coal layer, and we observe similar excursions within other carbon-rich lithologies. Given that we cannot disentangle local lithological effects from global atmospheric changes, we conclude that a negative δ13Corg excursion is not an unequivocal indicator of the KPB in the Hell Creek area.

Evaluating disparities in access to obstetric services for American Indian women across Montana.

Pregnant women across the rural United States have increasingly limited access to obstetric care, especially specialty care for high-risk women and infants. Limited research focuses on access for rural American Indian/Alaskan Native (AIAN) women, a population warranting attention given persistent inequalities in birth outcomes. Using Montana birth certificate data (2014-2018), we examined variation in travel time to give birth and access to different levels of obstetric care (i.e., the proportion of individuals living within 1- and 2-h drives to facilities), by rurality (Rural-Urban Continuum Code) and race (White and AIAN people). Results point to limited obstetric care access in remote rural areas in Montana, especially higher-level specialty care, compared to urban or urban-adjacent rural areas. AIAN women traveled significantly farther than White women to access care (24.2 min farther on average), even compared to White women from similarly rural areas (5-13 min farther, after controlling for sociodemographic characteristics, risk factors, and health care utilization). AIAN women were 20 times more likely to give birth at a hospital without obstetric services and had less access to complex obstetric care. Poor access was particularly pronounced among reservation-dwelling AIAN women. It is imperative to consider racial disparities and health inequities underlying poor access to obstetric services across rural America. Current federal policies aim to reduce maternity care professional shortages. Our findings suggest that racial disparities in access to complex obstetric care will persist in Montana unless facility-level infrastructure is also expanded to reach areas serving AIAN women.

Greater Contribution From Agricultural Sources to Future Reactive Nitrogen Deposition in the United States

AbstractMany sensitive ecosystems in areas protected for biodiversity conservation in the United States suffer from exposure to excess reactive nitrogen (Nr) released by fossil fuel combustion and agricultural practices and deposited onto the land surface and water bodies. The Community Multiscale Air Quality (CMAQ) model was applied over the contiguous United States to link emissions and climate change to reactive nitrogen deposition by simulating both present‐day and future speciated Nr deposition to protected areas. Future conditions included examining the Representative Concentration Pathway 8.5 climate and the Shared Socio‐Economic Pathway 5 emission scenarios. We further identify protected areas that would benefit most from better Nr management strategies by comparing the simulated deposition with multiple critical loads (CLs) for both biodiversity and acidification in terrestrial and aquatic ecosystems. Achieved by further NOx emission reductions from the mobile and power generation sectors, future Nr deposition is expected to decrease. However, in regions with intensive fertilizer application or hosting concentrated animal feeding operations, the reduction may be offset by rising agricultural NH3 emissions. The protected areas having CL exceedances in 2050 are expected to increase by 5.5% for empirical lichen‐based CL, and by 11% and 22% for surface water and forest soil acidity, respectively, because of the agricultural NH3 emission increase. By linking the deposition simulations with a water quality model, we identified that atmospheric deposition is the dominant source of nitrogen for several remote watersheds, including several lakes in National Parks and National Wilderness areas in Colorado, Montana, and Minnesota.

Health Risk Assessment of Dietary Heavy Metals Intake from Fruits and Vegetables Grown in Selected Old Mining Areas-A Case Study: The Banat Area of Southern Carpathians.

In this study, we conducted a noncarcinogenic risk assessment of consuming vegetables and fruits grown in two old mining areas from the Banat area of Southern Carpathians (Romania), Moldova Veche (M) and Rusca Montana (R) and in a nonpolluted reference area located near the village of Borlova (Ref). Concentrations of Fe, Mn, Zn, Cu, Ni, Cd and Pb in soils and commonly eaten vegetables and fruits were measured and used for calculating the weighted estimated daily intake of metals (WEDIM), the target hazard quotients (THQ) and the total target hazard quotients (TTHQ) for normal daily consumption in adults. Levels of certain metals in soils and plants from the R area (Pb) and the M area (Cu) were higher than those measured in the Ref area—and often exceeded normal or even alert-threshold levels. TTHQs for the R area (1.60; 6.03) and the M area (1.11; 2.54) were above one for leafy vegetables and root vegetables, respectively, suggesting a major risk of adverse health effects for diets, including these vegetal foodstuffs. Moreover, THQ and TTHQ indicated a higher population health risk for the R area than for the M area, with the Ref area being a safe zone.

Registration of ‘Dagmar’ hard red spring wheat

Abstract‘Dagmar’ hard red spring wheat (Triticum aestivum L.) (Reg. no. CV‐1158, PI 690450) was released by the Montana Agricultural Experiment Station because of its excellent yield potential in dryland areas of Montana, solid stems, and superior end‐use quality. Dagmar was a selection from the cross MT1133/MT1148 and was tested as experimental line MT1621. Dagmar has similar grain yield potential to ‘Vida’, the most widely grown cultivar in Montana. Stems of Dagmar are more solid than those of Vida, suggesting increased resistance to the wheat stem sawfly (Cephus cinctus Norton). Dagmar has higher grain protein and stronger gluten than Vida. Thus, Dagmar should be useful in Montana and adjoining states facing drought and wheat stem sawfly pressure.

Behavioral complexities at high elevation: assessing prehistoric landscape use in the alpine regions of the Greater Yellowstone Ecosystem

Alpine landscapes capture our imaginations. Envisioning these forbidding regions occupied by humans in prehistory has drawn academic and public audiences alike. The history of these alpine regions is being rewritten the world over, due in part to recent archaeological discoveries made in the alpine regions of the Greater Yellowstone Ecosystem (GYE). These discoveries, some in the wilderness areas of Montana, have revealed a complex tapestry of prehistoric lifeways. Archaeological and paleobiological research in Montana’s GYE alpine regions by Dr. Craig Lee (INSTAAR/ PCRG), Dr. Rachel Reckin (USFS) and Scott Dersam (PCRG) have spearheaded these continued multi-disciplinary studies in the region. Their efforts have focused on the climatological, ecological, as well as cultural impacts of ice patch use and alpine habitation on patterns of prehistoric occupation in the region. The UW-NPS Research Station Small Grant funded archaeological research and reconnaissance of the alpine regions of Montana’s Beartooth wilderness during the summer 2019. The 2019-field season’s discoveries added significant knowledge to regional research in high elevation studies, documenting the highest known stone circles, ceramics, and Paleoindian hunting activities in Montana.
 
 Featured photo from figure 4 in report.

Wildfires Influence Abundance, Diversity, and Intraspecific and Interspecific Trait Variation of Native Bees and Flowering Plants Across Burned and Unburned Landscapes

Wildfire regimes are changing in the western United States, yet we have little basic understanding of how wildfires influence native bees, the resources they depend on for food and nesting, or the traits that influence their interactions with plants. In burned and unburned areas in Montana, USA, we investigated the abundance and diversity of native bees, floral and nesting resources, nesting success, and traits of flowers and bees. In two of the three localities studied, burned areas, including areas that burned with high-severity wildfires, supported higher density and diversity of native bees and the flowers they depend on for food and larval provisioning. Burned areas also had more bare ground for ground-nesting bees and more available coarse woody debris for cavity-nesting bees than unburned areas. Moreover, cavity-nesting bees were completely unsuccessful at nesting in artificial nesting boxes in unburned areas, while nesting success was 40% in burned areas. Mean bee intertegular distance (a trait strongly correlated with tongue length, foraging distance, and body size) was similar between burned and unburned areas. However, wildfires influenced both interspecific and intraspecific trait variation of bees and plants. Intraspecific variation in bee intertegular distance was higher in unburned than burned areas. Both interspecific and intraspecific variation in floral traits important for interactions with pollinators were generally higher in burned than unburned areas. Thus, wildfires generally increased the density and species diversity of bees and flowers as well as trait variation at both trophic levels. We conclude that wildfires – even large, high-severity wildfires – create conditions that support native bees and the resources they need to flourish, but that unburned areas maintain trait variation in landscape mosaics with heterogeneous fire conditions.

Numerical modeling of a regional groundwater flow system to assess groundwater storage loss, capture and sustainable exploitation of the transboundary Milk River Aquifer (Canada – USA)

Groundwater capture and storage loss play a major role in the sustainable exploitation of a regional aquifer. This study aimed to identify the impact of major and long-term groundwater exploitation on a regional aquifer system to understand the processes controlling the sustainable exploitation of the transboundary Milk River Aquifer (MRA). The MRA extends over 26,300 km2, being a major water resource across southern Alberta (Canada) and northern Montana (USA). Concerns about the sustainability of the MRA were raised as the century-old exploitation has led to important drawdowns and the local loss of historical artesian conditions. A steady-state numerical model of the regional flow system was developed and calibrated against hydraulic heads, groundwater fluxes, and the area with flowing artesian wells. Four groundwater abstraction scenarios were simulated: 1) natural flow conditions without exploitation; 2) the mean abstraction rate over the last 108 years; 3) the historical maximum global abstraction rate of the MRA; and 4) a theoretical high abstraction rate based on the maximum rate estimated for each MRA exploitation zone. The numerical model agrees with the previously formulated conceptual model and supports its hydraulic plausibility. Results show that MRA exploitation has led to a major change in flow patterns to sustain groundwater abstraction. The MRA water balance under exploitation indicates that more recharge and reduced seepage to bedrock valleys compensate groundwater withdrawals. Based on its impact on regional discharge and the reduction in MRA storage, the mean historical level of exploitation of the MRA appears sustainable. Larger exploitation rates would significantly reduce groundwater discharge to surface seepage locations and lead to a larger reduction in groundwater storage in the MRA. Modeling also illustrates that the MRA is an internationally shared resource. This situation would justify a joint management of the aquifer system between Canada and USA; especially in the area comprised between the recharge area in Montana and the Canadian reach of the Milk River.

Survival Estimates and Cause of Mortality of Golden Eagles in South-Central Montana

Golden Eagles are a long-lived, wide-ranging bird of conservation concern in North America. To create a comprehensive conservation strategy, managers and researchers need to know the primary causes of mortality and must have reliable survival estimates. We monitored nesting Golden Eagles in a 2700 km2 area of south-central Montana from 2010–2017. As part of our effort, we fitted 16 adult and 13 nestlings with platform terminal transmitters for satellite telemetry. We determined causes of mortality from recovered Golden Eagles and, using multi-state models in program MARK, we estimated monthly and annual survival probabilities. We confirmed five total mortalities, including two cases of lead toxicity, one occurrence of intraspecific aggression, and two mortalities with unknown cause. The monthly survival estimate of adult Golden Eagles in our study area was 0.994 and the annual adult survival probability was 0.930. The monthly survival probability estimate from birds transmittered as nestlings was 0.991 and the annual survival estimate was 0.897. Lead toxicity and intraspecific aggression are known causes of Golden Eagle mortality, but the birds we tracked died from lead toxicity at a higher rate than would be expected based on results from other studies. The survival probability estimates from the Golden Eagles we monitored were higher than reported estimates from other locations. Further, the information we provide can assist with the development of population matrices and increase our knowledge on causes of Golden Eagle mortality.