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Western Ecological Research Center (WERC)

The Western Ecological Research Center (WERC) is a USGS Ecosystems Mission Area operation serving primarily California and Nevada. WERC scientists work closely with Federal, State, academic, and other collaborators to address a diverse array of high-profile topics. Topics include research on effects of wildfire, sea level rise, drought, energy development and more on federal Trust species.

News

2025 in Review: The Saline Lake Ecosystems Integrated Water Availability Assessment

2025 in Review: The Saline Lake Ecosystems Integrated Water Availability Assessment

Earth Science Matters - Vol. 21 | Issue 1

Earth Science Matters - Vol. 21 | Issue 1

Helping the California Winter Rice Habitat Incentive Program increase bird use of winter-flooded rice fields

Helping the California Winter Rice Habitat Incentive Program increase bird use of winter-flooded rice fields

Publications

Distribution and abundance of Least Bell’s Vireos (Vireo bellii pusillus) and Southwestern Willow Flycatchers (Empidonax traillii extimus) at the Mojave River Dam, San Bernardino County, California—2025 Data Summary Distribution and abundance of Least Bell’s Vireos (Vireo bellii pusillus) and Southwestern Willow Flycatchers (Empidonax traillii extimus) at the Mojave River Dam, San Bernardino County, California—2025 Data Summary

Executive Summary We surveyed for Least Bell’s Vireos (Vireo bellii pusillus; vireo) and Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) at the Mojave River Dam study area near Hesperia, California, in 2025. Four vireo surveys were completed between April 23 and June 26, 2025, and three flycatcher surveys were completed between May 16 and June 26, 2025. We...
Authors
Scarlett L. Howell, Barbara E. Kus

Distribution and Abundance of Least Bell’s Vireo (Vireo bellii pusillus) and Southwestern Willow Flycatcher (Empidonax traillii extimus) at the Sepulveda Dam Basin, Los Angeles County, California—2025 Data Summary Distribution and Abundance of Least Bell’s Vireo (Vireo bellii pusillus) and Southwestern Willow Flycatcher (Empidonax traillii extimus) at the Sepulveda Dam Basin, Los Angeles County, California—2025 Data Summary

Executive Summary We surveyed for Least Bell’s Vireos (Vireo bellii pusillus; vireo) and Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) along Bull Creek, Haskell Creek, and the Los Angeles River (Sepulveda Dam project area) in Los Angeles County, California, in 2025. Four vireo surveys were completed between April 16 and July 2, 2025, and three flycatcher...
Authors
Lisa D. Allen, Barbara E. Kus

Southwestern Willow Flycatcher (Empidonax traillii extimus) surveys at the city of Carlsbad Preserve, San Diego County, California—2025 data summary Southwestern Willow Flycatcher (Empidonax traillii extimus) surveys at the city of Carlsbad Preserve, San Diego County, California—2025 data summary

Executive Summary We surveyed for Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) at five survey areas within the City of Carlsbad Preserve, Carlsbad, California, in 2025. Three flycatcher surveys were completed between May 16 and June 30, 2025. One transient flycatcher was observed at the Lake Calavera survey area in the City of Carlsbad Preserve in 2025.
Authors
Lisa D. Allen, Barbara E. Kus

Science

Science for management of America’s iconic wild horses and burros

Wild horses and burros are iconic wildlife of the western USA as well as a complicated management issue on tribal, state, and federal lands. Due to their history as domesticated animals, these wild equids – also called “free-roaming” or “feral” equids – can reproduce quickly, and have few natural predators, allowing their populations to grow rapidly if not managed. When populations are too large...
Science for management of America’s iconic wild horses and burros

Science for management of America’s iconic wild horses and burros

Wild horses and burros are iconic wildlife of the western USA as well as a complicated management issue on tribal, state, and federal lands. Due to their history as domesticated animals, these wild equids – also called “free-roaming” or “feral” equids – can reproduce quickly, and have few natural predators, allowing their populations to grow rapidly if not managed. When populations are too large...
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Greater Sage-Grouse Population Monitoring Framework: Cheat Sheet

The Greater Sage-grouse Population Monitoring Framework fills a prominent information gap to help inform current assessments of sage-grouse population trends at nested spatial and temporal scales. It is centered on four objectives: (1) create a standardized database of lek counts; (2) develop biologically based spatial population structures by clustering leks; (3) estimate spatial trends at...
Greater Sage-Grouse Population Monitoring Framework: Cheat Sheet

Greater Sage-Grouse Population Monitoring Framework: Cheat Sheet

The Greater Sage-grouse Population Monitoring Framework fills a prominent information gap to help inform current assessments of sage-grouse population trends at nested spatial and temporal scales. It is centered on four objectives: (1) create a standardized database of lek counts; (2) develop biologically based spatial population structures by clustering leks; (3) estimate spatial trends at...
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Greater Sage-Grouse Population Monitoring Framework: Targeted Annual Warning System Information Sheet

The Greater Sage-grouse Population Monitoring Framework helps fill a major information gap to aid current assessments of sage-grouse population trends across spatial and temporal scales. It centers on four objectives: 1) create a standardized database of lek counts; 2) cluster leks to develop spatial population structures; 3) estimate spatial trends across temporal extents; and 4) develop a system...
Greater Sage-Grouse Population Monitoring Framework: Targeted Annual Warning System Information Sheet

Greater Sage-Grouse Population Monitoring Framework: Targeted Annual Warning System Information Sheet

The Greater Sage-grouse Population Monitoring Framework helps fill a major information gap to aid current assessments of sage-grouse population trends across spatial and temporal scales. It centers on four objectives: 1) create a standardized database of lek counts; 2) cluster leks to develop spatial population structures; 3) estimate spatial trends across temporal extents; and 4) develop a system...
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