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Publications

Below is a list of available NOROCK peer reviewed and published science. If you are in search of a specific publication and cannot find it below or through a search, please contact twojtowicz@usgs.gov.

Filter Total Items: 1357

Seasonal migrations and other movements Seasonal migrations and other movements

In the past 25 years new information has been obtained on the migrations and movements of mountain sheep (bighorn [Ovis canadensis], thinhorn [Ovis dalli]). This chapter provides a comprehensive overview of mountain sheep migration and other movements across their broad distribution in western North America. Across the range of mountain sheep, migrations and other seasonal movements...
Authors
Blake Lowrey

Integrating climate and anthropogenic dynamics can inform multifaceted management for declining mule deer populations Integrating climate and anthropogenic dynamics can inform multifaceted management for declining mule deer populations

Wildlife and their habitats face profound challenges from climate and landscape-scale changes that extend beyond the influence and time horizon of most biologists and land managers. In this changing environment, long-term datasets can enhance assessments of how demographic trends respond to interactions among local (e.g., habitat restoration decisions) and broad extent drivers, including...
Authors
Teagan A. Hayes, Aaron N. Johnston, L. Embere Hall, Jill E. Randall, Matthew J. Kauffman, Christopher Keefe, Kevin Monteith, Tabitha A. Graves

Environmental DNA pilot monitoring program for invasive species and biodiversity assessments on Santa Cruz Island: Interim report, September 2025 Environmental DNA pilot monitoring program for invasive species and biodiversity assessments on Santa Cruz Island: Interim report, September 2025

The U.S. Geological Survey (USGS) and Southern California Coastal Water Research Project supported Channel Islands National Park, The Nature Conservancy’s (TNC) Santa Cruz Island Preserve, and University of California San Diego (UCSD) researchers in using environmental DNA sampling to monitor for invasive Argentine ant (Linepithema humile) and to describe spatial biodiversity patterns in...
Authors
Adam J. Sepulveda, Susanna Theroux

Mountain goat declines in a protected, interior, native population Mountain goat declines in a protected, interior, native population

A shifting climate poses threats to alpine-adapted species including mountain goats. We used long-term (12 years) citizen science monitoring data and Bayesian N-mixture modeling to estimate population trends and drivers of population metrics among mountain goats in Glacier National Park (GNP). Median goats per site (n = 37 sites) declined by 45% (95% credible interval [CRI] = 32%, 57%)...
Authors
Tabitha A. Graves, William Michael Janousek, Michael Yarnall, Jami Belt

An energetic tradeoff best explains parturition timing in grizzly bears An energetic tradeoff best explains parturition timing in grizzly bears

Timing of grizzly bear (Ursus arctos) parturition during hibernation has been explained by ancestral traits (delayed implantation, altricial young, obligate maternal denning), but the ultimate driver underlying precise timing has not been fully explored. Capitalizing on an observed latitudinal increase in denning duration among four populations in interior North America, we tested two...
Authors
C. M. Costello, Lori L. Roberts, D. D. Bjornlie, M. D. Cameron, J. G. Clapp, Mark A. Haroldson, G. V. Hilderbrand, Kyle Joly, Wayne F. Kasworm, J. M. Nicholson, Thomas G. Radandt, M. S. Sorum, J. E. Teisberg, Frank T. van Manen, M. A. Vinks

Annual grass invasion is transforming the sagebrush biome’s songbird communities Annual grass invasion is transforming the sagebrush biome’s songbird communities

Novel stressors like climate change and biological invasions alter ecological communities, resulting in changes to ecosystem services and biodiversity (that is, ecological transformation). Most ecological transformation research focuses on plants, but animals are likely affected by and plausibly mediate the extent, impact, and pace of transformations. In western North America, where...
Authors
Brendan K. Hobart, Wynne Emily Moss, Max C Cook, R. Chelsea Nagy, Valerie J McKenzie

Status assessment of peregrine falcons in North America using integrated population models Status assessment of peregrine falcons in North America using integrated population models

Species status assessments require an understanding of underlying population dynamics and important drivers of species demography. Large-scale assessments can be difficult due to challenges collating data obtained through different methods and different sources at multiple scales. Integrated population models (IPMs) provide a unified framework to combine multiple data sources and jointly...
Authors
Michael J. Gould, Ted Swem, Guthrie S. Zimmerman, Brian A. Millsap, Jay V. Gedir, Fitsum Abadi

A summary of grizzly bear distribution in the lower-48 US states in 2024 A summary of grizzly bear distribution in the lower-48 US states in 2024

Understanding the distribution of grizzly bear populations in the lower-48 states, is important for their conservation and management, and for public safety. Previously, our research teams working in grizzly bear ecosystems in the lower-48 states used varying methods to estimate distribution of grizzly bear populations. In the Greater Yellowstone Ecosystem (GYE) and Northern Continental...
Authors
Cecily M. Costello, Justin A. Dellinger, Jennifer K. Fortin-Noreus, Mark A. Haroldson, Bryn Karabensh, Wayne F. Kasworm, Lori L. Roberts, Justin E. Teisberg, Frank T. van Manen, Tyler J. Vent

Evaluating mountain goat population structure in Glacier National Park and Waterton Lakes National Park Evaluating mountain goat population structure in Glacier National Park and Waterton Lakes National Park

Mountain goats are an iconic, climate-sensitive species across their North American alpine range. Among its nearly complete complement of native wildlife, no single species embodies Glacier National Park (GNP) more than the mountain goat. They play an important role as an alpine food source for many of the park’s carnivores including wolverines, mountain lions, and grizzly bears...
Authors
Tabitha A. Graves, Eliza Stein, Lindsay M Dose, Rachel S. Crowhurst, Heather Thomas, Clinton W. Epps, Rob Found, Jami Belt, Mark Biel

Leveraging an observed-data likelihood improves the use of machine learning labels in a Bayesian hierarchical model for bioacoustic data Leveraging an observed-data likelihood improves the use of machine learning labels in a Bayesian hierarchical model for bioacoustic data

Classification of massive datasets by machine learning (ML) algorithms is promising for many scientific domains, especially wildlife monitoring programs that rely on passive acoustic surveys for detecting species. However, treating ML-predicted class labels (e.g., species identity) as truth biases inferences of focal parameters within common modeling frameworks. One solution is to model...
Authors
Jacob Oram, Katharine M. Banner, Christian Stratton, Andrew Hoegh, Kathryn M. Irvine

Comparison of methods for estimating wild turkey poult survival Comparison of methods for estimating wild turkey poult survival

Eastern wild turkey (Meleagris gallopavo silvestris) population growth is driven by variation in reproduction, and poult survival is a crucial vital rate. Traditional poult survival monitoring uses flush counts of radio-tagged females, but brood flocking (when broods and females merge into larger flocks) and mark retention are potential problems with this method and can produce biased...
Authors
Joseph O. Quehl, Lindsey M. Phillips, Vincent A. Johnson, Joseph D. Clark, Craig A. Harper, David A. Buehler
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