Sarah Peterson | U.S. Geological Survey
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Sarah Peterson
Wildlife Biologist
Western Ecological Research Center (WERC)
Email
sepeterson@usgs.gov
Phone
530-669-5088
0000-0003-2773-3901
800 Business Park Drive Suite D
Dixon
CA
95620
United States
Expertise
animals
capturing (animals)
carnivores
migratory species
migration (organisms)
vertebrates
wildlife
wildlife population management
plant and animal testing
aquatic ecosystems
ecosystems
contamination and pollution
human impacts
toxic trace element contamination
coastal ecosystems
marine ecosystems
isotopic analysis
laboratory methods
Dr. Sarah Peterson is a Wildlife Biologist at the Dixon Field Station.
She is broadly interested in the ecology and movement of upper trophic level predators, with a focus on birds and mammals. Additionally, she is interested in the interplay between foraging ecology and both contaminant bioaccumulation and toxicological risk. She conducted her PhD at UC Santa Cruz, where she examined how ecology and physiology influence contaminant bioaccumulation (mercury and persistent organic pollutants) in seals and sea lions.
Currently, she works as part of a large collaborative research effort to study ground-nesting waterfowl at the Grizzly Island Wildlife Area. She leads a portion of the study that quantifies survival and movement of ducklings, using VHF radio-telemetry. She also quantifies the space use and movements of raccoons and skunks around duck nests using GPS technology.
Education
Ph.D. 2015. Ecology and Evolutionary Biology. University of California Santa Cruz, CA (UCSC)
M.Sc. 2008. Marine and Estuarine Science. Dept. of Biology. Western Washington University, WA (WWU)
B.A. 2005. Biology and Environmental Studies. Whitman College, WA
Professional Research Experience
Wildlife Biologist
, USGS, Western Ecological Research Center (2015–present)
Doctoral Researcher
, Ecology, Physiology & Conservation of Marine Animals Lab, Dept. of Ecology and Evolutionary Biology, UCSC (2010–2015)
Biological Technician (shorebird & seabird research)
, USGS, Western Ecological Research Center (2010)
Biological Technician & Volunteer
, Yellowstone Gray Wolf Recovery Program, Yellowstone National Park (2008–2009 & 2015)
Masters Research
, Marine Mammal Ecology Lab, Dept. of Biology, WWU (2006–2008)
Graduate Student Research Assistant
, Marine Mammal Ecology Lab, Dept. of Biology, WWU (2007)
Biological Researcher
, Ecological Research Station, Öland, Sweden (2004)
Field Assistant
, Botswana Wild Dog Research Camp, Botswana, Africa (2003)
Outreach and Education
Graduate Student TA
, Dept. of Ecology and Evolutionary Biology, UCSC (2011, 2014 & 2015)
Naturalist & Kayak Guide
, CA, WA, & southeast AK (2005–2015)
Graduate Student TA
, Dept. of Biology, WWU (2007–2008)
GK-12 National Science Foundation Fellow
(graduate students in K-12 education), Dept. of Biology, WWU (2006–2007)
Science Instructor
, The Ocean Institute, CA (2005–2006)
Science and Products
Data
Multimedia
Publications
Web Tools
Software
News
Filter Total Items: 17
February 27, 2026
Dabbling Duckling Habitat Use and Movements
Dabbling Duckling Habitat Use and Movements
We conducted a multi-year study (2016-2019) to identify elements of wetland habitat management that could potentially benefit breeding ducks. Specifically, we examined the influence of habitat variables in explaining habitat selection of managed wetlands near upland nesting sites by radio-tagged Mallard (Anas platyrhynchos) and Gadwall (Mareca strepera) ducklings in a brackish marsh...
By
Western Ecological Research Center (WERC)
July 15, 2025
Long-term Trends in Spring and Summer-flooded Wetland area in Suisun Marsh, California
Long-term Trends in Spring and Summer-flooded Wetland area in Suisun Marsh, California
We digitized water on the landscape for breeding waterfowl and other wetland-associated species within Suisun Marsh (California, USA) twice each year (spring and summer) during a 38-year period (1984-2021) with remote sensing methods that combined Landsat satellite imagery (composite images) and spectral mixture analysis using Google Earth Engine. This dataset contains the amount of...
By
Western Ecological Research Center (WERC)
August 15, 2024
Bird use of Winter-Flooded Rice Fields in the Sacramento Valley, California
Bird use of Winter-Flooded Rice Fields in the Sacramento Valley, California
Bird and habitat surveys were conducted in winter-flooded rice fields in the Sacramento Valley, California, USA during the fall and winters of 2021-2022 (Oct 2021 through February 2022) and 2022-2023 (December 2022 through February 2023). Rice field sampling consisted of (1) a bird survey that was followed by (2) an overall habitat assessment and (3) a more detailed habitat transect...
By
Western Ecological Research Center (WERC)
May 17, 2024
Duckling Survival in a Brackish Marsh
Duckling Survival in a Brackish Marsh
We conducted a multi-year study (2016-2019) to quantify sources of duckling mortality, identify predator type, and estimate survival rates for Mallard (Anas platyrhynchos) and Gadwall (Mareca strepera) ducklings within Suisun Marsh, California.
By
Western Ecological Research Center (WERC)
April 29, 2024
Methylmercury Effects on Birds: Bibliography and Dataset for the Development of Toxicity Reference Values for Injury Assessment
Methylmercury Effects on Birds: Bibliography and Dataset for the Development of Toxicity Reference Values for Injury Assessment
This data release contains three files. The first (Table S1 Bibliography Dataset) contains the entire bibliography for the 435 publications examined for potential inclusion into at least one of the meta-analyses for the effects of environmental mercury (Hg) on birds. For those 168 publications that were included in at least one meta-analysis, the worksheet titled Bibliography contains...
By
Western Ecological Research Center (WERC)
February 20, 2024
Egg Membrane Thickness in 13 Waterbird Species
Egg Membrane Thickness in 13 Waterbird Species
Eggshells of 13 waterbird species were divided in half longitudinally and the outer eggshell membrane was removed from one of the halves. Eggshell thickness was measured for both eggshell halves, both with and without the outer eggshell membrane. The eggshell membrane thickness was calculated by taking the difference between the two thickness measurements. These data support the...
By
Western Ecological Research Center (WERC)
February 7, 2024
Maternal Transfer of Mercury to Northern Elephant Seal Pups
Maternal Transfer of Mercury to Northern Elephant Seal Pups
We used free-ranging northern elephant seals as a model species to investigate maternal transfer of mercury (Hg) to pups in relation to maternal traits, including maternal blood mercury concentrations, and to quantify the links between pup lanugo mercury concentrations and maternal mesopelagic foraging behavior during gestation. We satellite tracked known-age adult females at sea during...
By
Western Ecological Research Center (WERC)
January 26, 2024
Eggshell Thickness in 5 Songbird Species
Eggshell Thickness in 5 Songbird Species
Eggshell thickness was measured at the egg equator and sharp pole for 5 songbird species. Each egg has thickness measurements at two locations on the egg and the corresponding egg length, egg width, egg volume, relative incubation age, egg identification, and nest identification. These data support the following publication: Schacter, C.R., Peterson, S.H., Hartman, C.A., Herzog, M.P...
By
Western Ecological Research Center (WERC)
April 5, 2023
Mercury, Cortisol, and Blood Biomarkers in Adult Female Northern Elephant Seals from 2011 to 2021
Mercury, Cortisol, and Blood Biomarkers in Adult Female Northern Elephant Seals from 2011 to 2021
This dataset represents 179 unique adult female northern elephant seals that were sampled between 2011 and 2021 during four different life history states (early breeding, late breeding, early molting, and late molting) at the Ano Nuevo colony in California, USA. Some individual seals were sampled multiple times, resulting in a total of 313 tissue samples. Tissue samples were collected...
By
Western Ecological Research Center (WERC)
September 20, 2022
Predator Movements and Duck Nests in Relation to Habitat Features in Suisun Marsh, CA (2016-2019)
Predator Movements and Duck Nests in Relation to Habitat Features in Suisun Marsh, CA (2016-2019)
This dataset describes mesopredator locations (raccoons and striped skunks), dabbling duck nest locations (mallard, gadwall, and cinnamon teal), northern harrier nest locations, and random locations in relation to a set of habitat features in Suisun Marsh, California during 2016 through 2019. We designed a series of questions to link fine-scale predator movements and vulnerability of...
By
Western Ecological Research Center (WERC)
August 17, 2022
Data measuring avian influenza infection, mercury concentration, and body condition in wild waterfowl
Data measuring avian influenza infection, mercury concentration, and body condition in wild waterfowl
These data represent mercury contamination, influenza infection, and body condition in 11 species of dabbling and diving ducks in the Pacific Flyway. These data support a USGS lead scientific publication.
By
Eastern Ecological Science Center
February 23, 2022
Nocturnal Incubation Recess and Flushing Behavior by Duck Hens Nesting in Grizzly Island Wildlife Area 2015-2018
Nocturnal Incubation Recess and Flushing Behavior by Duck Hens Nesting in Grizzly Island Wildlife Area 2015-2018
This dataset describes nocturnal incubation recess behavior for mallard and gadwall hens nesting in Grizzly Island Wildlife Area in breeding seasons 2015-2018. It includes the frequency, start time and duration of recesses, and details a method for determining whether a recess was initiated in response to a predator at the nest using nest temperature data. These data support the...
By
Western Ecological Research Center (WERC)
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
February 2, 2018
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
USGS scientist holds a young skunk with an ear tag ID and a lightweight GPS collar. The USGS is studying the movement patterns of skunks and raccoons in Suisun Marsh, CA to learn how they use different landscape features, like levee roads, to navigate to waterfowl nests.
By
Western Ecological Research Center (WERC)
February 2, 2018
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
USGS scientist holds a young skunk with an ear tag ID and a lightweight GPS collar. The USGS is studying the movement patterns of skunks and raccoons in Suisun Marsh, CA to learn how they use different landscape features, like levee roads, to navigate to waterfowl nests.
By
Western Ecological Research Center (WERC)
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
February 25, 2017
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
USGS field scientist uses radio telemetry to search for skunks and raccoons tagged with lightweight radio collars. USGS is monitoring skunk and raccoon movements across California's inland marshes to understand how they are using different features of the landscape, like levee roads, to navigate to waterfowl nests.
By
Western Ecological Research Center (WERC)
February 25, 2017
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
USGS field scientist uses radio telemetry to search for skunks and raccoons tagged with lightweight radio collars. USGS is monitoring skunk and raccoon movements across California's inland marshes to understand how they are using different features of the landscape, like levee roads, to navigate to waterfowl nests.
By
Western Ecological Research Center (WERC)
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
July 1, 2016
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Photo of a skunk with an ear tag ID. Scientists from the USGS Western Ecological Research Center are studying the movements of skunks and raccoons within Suisun Marsh, CA to understand how they navigate the marsh to reach waterfowl nests. Results will inform the management of waterfowl populations within the Central Valley, CA.
By
Western Ecological Research Center (WERC)
July 1, 2016
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Photo of a skunk with an ear tag ID. Scientists from the USGS Western Ecological Research Center are studying the movements of skunks and raccoons within Suisun Marsh, CA to understand how they navigate the marsh to reach waterfowl nests. Results will inform the management of waterfowl populations within the Central Valley, CA.
By
Western Ecological Research Center (WERC)
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
June 8, 2016
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA.
By
Western Ecological Research Center (WERC)
June 8, 2016
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA.
By
Western Ecological Research Center (WERC)
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
May 23, 2016
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall ducklings in nest, Suisun Marsh, CA.
By
Western Ecological Research Center (WERC)
May 23, 2016
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall ducklings in nest, Suisun Marsh, CA.
By
Western Ecological Research Center (WERC)
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
April 13, 2016
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS biological science technician Andrew Greenawalt holding a duckling with a lightweight radio transmitter. The USGS Western Ecological Research Center is monitoring waterfowl populations throughout Suisun Marsh, CA, and the greater Pacific Flyway. Radio transmitters fall off within several weeks and are recovered by scientists for data collection.
By
Western Ecological Research Center (WERC)
April 13, 2016
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS biological science technician Andrew Greenawalt holding a duckling with a lightweight radio transmitter. The USGS Western Ecological Research Center is monitoring waterfowl populations throughout Suisun Marsh, CA, and the greater Pacific Flyway. Radio transmitters fall off within several weeks and are recovered by scientists for data collection.
By
Western Ecological Research Center (WERC)
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
February 5, 2011
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male northern elephant seal (
Mirounga angustirostris
) resting on a sandy beach along the coast of California.
By
Western Ecological Research Center (WERC)
February 5, 2011
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male northern elephant seal (
Mirounga angustirostris
) resting on a sandy beach along the coast of California.
By
Western Ecological Research Center (WERC)
Filter Total Items: 38
September 18, 2025
Habitat features influencing waterbird use of managed wetlands enrolled in a public-private partnership for land conservation: The California Waterfowl Habitat Program
Habitat features influencing waterbird use of managed wetlands enrolled in a public-private partnership for land conservation: The California Waterfowl Habitat Program
Draining, water diversion, and development have greatly reduced the availability of freshwater wetland habitat around the world, and many remaining wetlands are on private lands. Public–private partnership programs can be an important means for promoting habitat conservation and management on private lands. We investigated bird use of 117 wetlands enrolled in the California Waterfowl...
Authors
C. Alex Hartman, Joshua T. Ackerman, Sarah H. Peterson, Brady Lynn Fettig, Mark P. Herzog
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
November 20, 2024
Bird habitat value and management priorities of the California Winter Rice Habitat Incentive Program
Bird habitat value and management priorities of the California Winter Rice Habitat Incentive Program
Flooding rice (Oryza sativa) agricultural fields during winter to facilitate rice straw decomposition has mitigated the loss of some of the natural wetlands in California’s Central Valley. We conducted bird surveys in 253 rice checks (2,158 ha) within 177 rice fields in the Sacramento Valley during the fall and winter of 2021-2022 and 2022-2023 to evaluate factors influencing bird use of...
Authors
Sarah H. Peterson, Joshua T. Ackerman, Carley R. Schacter, C. Alex Hartman, Mark P. Herzog
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
August 12, 2024
Body mass changes of dabbling and diving ducks wintering in California
Body mass changes of dabbling and diving ducks wintering in California
Bird body mass is often used as an index of body condition and fluctuates throughout the year in response to environmental conditions and avian life-history events. We examined the body mass of 59,572 ducks representing 13 species (7 dabbling duck species and 6 diving duck species) harvested within the 3 regions of the Central Valley in California, USA (Sacramento Valley, Suisun Marsh...
Authors
Mark P. Herzog, Joshua T. Ackerman, Jeffrey D. Kohl, Brady Lynn Fettig, C. Alex Hartman, Sarah H. Peterson, Michael L. Casazza, Joseph P. Fleskes
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
May 13, 2024
Duckling survival increased with availability of flooded wetland habitat and decreased with salinity concentrations in a brackish marsh
Duckling survival increased with availability of flooded wetland habitat and decreased with salinity concentrations in a brackish marsh
Waterfowl population recruitment is sensitive to duckling survival. We quantified predator types and survival rates for Anas platyrhynchos (Mallard) and Mareca strepera (Gadwall) ducklings in one of the largest brackish water marshes in western North America (Suisun Marsh, California) using 556 radio-tagged ducklings from 284 broods tracked during the 2016 to 2019 breeding seasons...
Authors
Sarah H. Peterson, Joshua T. Ackerman, C. Alex Hartman, Andrew C. Greenawalt, Michael L. Casazza, Mark P. Herzog
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
April 29, 2024
Methylmercury effects on birds: A review, meta-analysis, and development of toxicity reference values for injury assessment based on tissue residues and diet
Methylmercury effects on birds: A review, meta-analysis, and development of toxicity reference values for injury assessment based on tissue residues and diet
Birds are used as bioindicators of environmental mercury (Hg) contamination, and toxicity reference values are needed for injury assessments. We conducted a comprehensive review, summarized data from 168 studies, performed a series of Bayesian hierarchical meta-analyses, and developed new toxicity reference values for the effects of methylmercury (MeHg) on birds using a benchmark dose...
Authors
Joshua T. Ackerman, Sarah H. Peterson, Mark P. Herzog, Julie L. Yee
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
April 24, 2024
Eggshell membrane thickness and its contribution to total eggshell thickness for 13 waterbird species
Eggshell membrane thickness and its contribution to total eggshell thickness for 13 waterbird species
Eggshell thickness can be an indicator of environmental pollution in wild birds and shell quality in wild and domestic birds, but it is difficult to measure calcite eggshell thickness due to the presence of the adherent outer eggshell membrane. Eggshells of 13 waterbird species were divided in half longitudinally and the outer membrane was removed from one of the halves. Subsequently, we...
Authors
Gary M. Santolo, Sarah H. Peterson, Breanne Cooney, C. Alex Hartman, Mark P. Herzog, Joshua T. Ackerman
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
February 26, 2024
Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups
Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups
Deep ocean foraging northern elephant seals (Mirounga angustirostris) consume fish and squid in remote depths of the North Pacific Ocean. Contaminants bioaccumulated from prey are subsequently transferred by adult females to pups during gestation and lactation, linking pups to mercury contamination in mesopelagic food webs (200–1000 m depths). Maternal transfer of mercury to developing...
Authors
Sarah H. Peterson, Michael G. Peterson, Joshua T. Ackerman, Cathy Debier, Chandra Goetsch, Rachel R. Holser, Luis A. Huckstadt, Jennifer C. Johnson, Theresa R. Keates, Birgitte I. McDonald, Elizabeth A. McHuron, Daniel P. Costa
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
January 31, 2024
Eggshell thickness and egg morphometrics in five songbird species from the Central Valley, California
Eggshell thickness and egg morphometrics in five songbird species from the Central Valley, California
Avian eggshell thickness is an important life history metric in birds and has broad applications across disciplines ranging from animal behavior to toxicology. Empirical eggshell thickness values for songbirds (Order Passeriformes) are under-represented in the literature due to the difficulty of measuring smaller eggs using traditional methods. We used a Hall-effect thickness gauge to...
Authors
Carley R. Schacter, Sarah H. Peterson, C. Alex Hartman, Mark P. Herzog, Joshua T. Ackerman
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
May 19, 2023
Nest attendance, incubation constancy, and onset of incubation in dabbling ducks
Nest attendance, incubation constancy, and onset of incubation in dabbling ducks
In birds, parents must provide their eggs with a safe thermal environment suitable for embryonic development. Species with uniparental incubation must balance time spent incubating eggs with time spent away from the nest to satisfy self-maintenance needs. Patterns of nest attendance, therefore, influence embryonic development and the time it takes for eggs to hatch. We studied nest...
Authors
C. Alex Hartman, Joshua T. Ackerman, Sarah H. Peterson, Brady Lynn Fettig, Michael L. Casazza, Mark P. Herzog
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
April 1, 2023
Habitat use by breeding waterbirds in relation to tidal marsh restoration in the San Francisco Bay estuary
Habitat use by breeding waterbirds in relation to tidal marsh restoration in the San Francisco Bay estuary
The South Bay Salt Pond Restoration Project aims to restore many former salt production ponds, now managed for wildlife and water quality, to tidal marsh. However, because managed ponds support large densities of breeding waterbirds, reduction of pond habitat may influence breeding waterbird distribution and abundance. We investigated habitat use associated with breeding, feeding, and...
Authors
Carley Rose Schacter, C. Alex Hartman, Mark P. Herzog, Sarah H. Peterson, Max L. Tarjan, Yewei Wang, Cheryl Strong, Rachel Tertes, Neil Warnock, Joshua T. Ackerman
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
March 30, 2023
Mercury bioaccumulation and cortisol interact to influence endocrine and immune biomarkers in a free-ranging marine mammal
Mercury bioaccumulation and cortisol interact to influence endocrine and immune biomarkers in a free-ranging marine mammal
Mercury bioaccumulation from deep-ocean prey and the extreme life history strategies of adult female northern elephant seals (Mirounga angustirostris) provide a unique system to assess the interactive effects of mercury and stress on animal health by quantifying blood biomarkers in relation to mercury (skeletal muscle and blood mercury) and cortisol concentrations. The thyroid hormone...
Authors
Sarah H. Peterson, Joshua T. Ackerman, Rachel R. Holser, Birgitte I. McDonald, Daniel P. Costa, Daniel E. Crocker
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
November 11, 2022
Dabbling duck eggs hatch after nest abandonment in the wild
Dabbling duck eggs hatch after nest abandonment in the wild
In most birds, parental incubation of eggs is necessary for embryo development and survival. Using a combination of weekly nest visits, temperature dataloggers, infrared video cameras, and GPS tracking of hens, we documented several instances of duck eggs hatching after being abandoned by the incubating female. Of 2826 Mallard (Anas platyrhynchos) and Gadwall (Mareca strepera) nests...
Authors
Carley Rose Schacter, Brady Lynn Fettig, Sarah H. Peterson, C. Alex Hartman, Mark P. Herzog, Michael L. Casazza, Joshua T. Ackerman
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
February 26, 2021
Waterfowl Ecology in Suisun Marsh and the Pacific Flyway
Waterfowl Ecology in Suisun Marsh and the Pacific Flyway
Learn about waterfowl research by scientists at the USGS Western Ecological Research Center.
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
San Francisco Bay and Sacramento-San Joaquin Delta Estuary
April 29, 2024
Methylmercury Effects on Birds: Percent Injury Tool
Methylmercury Effects on Birds: Percent Injury Tool
Welcome to The Bird Mercury Tool website. Please follow the guidance below to download the tool and user guide. The Bird Mercury Tool: Estimating Methylmercury Injury to Birds can be used by practitioners to help interpret injury to birds caused by methylmercury concentrations in bird tissues or diet. The dataset, statistical models, and assumptions used within this tool have been...
By
Western Ecological Research Center (WERC)
Helping the California Winter Rice Habitat Incentive Program increase bird use of winter-flooded rice fields
December 29, 2025
Helping the California Winter Rice Habitat Incentive Program increase bird use of winter-flooded rice fields
The Central Valley of California provides important habitat for waterbirds (waterfowl, shorebirds, and wading birds).
Read Article
Duckling survival is higher if nests are closer to wetland habitats flooded during the summer
December 29, 2025
Duckling survival is higher if nests are closer to wetland habitats flooded during the summer
A recent USGS study, in collaboration with the California Department of Fish and Wildlife at the Grizzly Island Wildlife Area, investigates what type...
Read Article
Re-establishing Waterbird Breeding Colonies in San Francisco Bay
April 17, 2024
Re-establishing Waterbird Breeding Colonies in San Francisco Bay
Learn more about how our partners are using ​science and management to maintain and establish new ​bird ​nesting colonies in support of the South Bay...
Read Article
Research Spotlight: What Habitat Features Make Duck Nests Vulnerable to Raccoons and Striped Skunks?
April 20, 2023
Research Spotlight: What Habitat Features Make Duck Nests Vulnerable to Raccoons and Striped Skunks?
Research by USGS scientists finds that predator-specific behaviors can shape where duck nests are most vulnerable in Suisun Marsh, CA. The findings...
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Research Spotlight: High Salinity and Limited Wetlands Reduce Duckling Habitat for Waterfowl
October 5, 2021
Research Spotlight: High Salinity and Limited Wetlands Reduce Duckling Habitat for Waterfowl
A new publication by USGS scientists examines wetland availability and salinity in Suisun Marsh, with particular focus on the implications for young...
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Research Spotlight: New Study Explores Nocturnal Nest Breaks and Predation Events for Dabbling Ducks
August 18, 2021
Research Spotlight: New Study Explores Nocturnal Nest Breaks and Predation Events for Dabbling Ducks
A new study by USGS scientists, in collaboration with the California Department of Water Resources and California Department of Fish and Wildlife...
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Research Spotlight: Precise Eggshell Thickness Measurements To Inform Bird Ecology And Mercury Monitoring
February 10, 2021
Research Spotlight: Precise Eggshell Thickness Measurements To Inform Bird Ecology And Mercury Monitoring
In a study published in the journal Ecology and Evolution, USGS biologists provide precise eggshell thickness measurements for 12 species of birds...
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Research Spotlight: Wetland Habitats and Aquatic Prey May Drive High Hair Mercury Concentrations in Suisun Marsh Raccoons
February 3, 2021
Research Spotlight: Wetland Habitats and Aquatic Prey May Drive High Hair Mercury Concentrations in Suisun Marsh Raccoons
A new study by scientists from USGS in collaboration with the California Department of Water Resources has found that mercury concentrations detected...
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Research Spotlight: Ducklings Leave Nests in Early Morning, Suggesting Predator Avoidance
June 12, 2019
Research Spotlight: Ducklings Leave Nests in Early Morning, Suggesting Predator Avoidance
In a study published in the journal Ecology and Evolution, U.S. Geological Survey (USGS) biologists put small cameras next to duck nests to determine...
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Research Spotlight: New Guidelines and Tool for Assessing Mercury Contamination Using Bird Feathers
May 31, 2019
Research Spotlight: New Guidelines and Tool for Assessing Mercury Contamination Using Bird Feathers
In a study published in the journal Environmental Toxicology and Chemistry, U.S. Geological Survey (USGS) biologists provide a detailed approach and...
Read Article
Science and Products
Filter Total Items: 17
February 27, 2026
Dabbling Duckling Habitat Use and Movements
Dabbling Duckling Habitat Use and Movements
We conducted a multi-year study (2016-2019) to identify elements of wetland habitat management that could potentially benefit breeding ducks. Specifically, we examined the influence of habitat variables in explaining habitat selection of managed wetlands near upland nesting sites by radio-tagged Mallard (Anas platyrhynchos) and Gadwall (Mareca strepera) ducklings in a brackish marsh...
By
Western Ecological Research Center (WERC)
July 15, 2025
Long-term Trends in Spring and Summer-flooded Wetland area in Suisun Marsh, California
Long-term Trends in Spring and Summer-flooded Wetland area in Suisun Marsh, California
We digitized water on the landscape for breeding waterfowl and other wetland-associated species within Suisun Marsh (California, USA) twice each year (spring and summer) during a 38-year period (1984-2021) with remote sensing methods that combined Landsat satellite imagery (composite images) and spectral mixture analysis using Google Earth Engine. This dataset contains the amount of...
By
Western Ecological Research Center (WERC)
August 15, 2024
Bird use of Winter-Flooded Rice Fields in the Sacramento Valley, California
Bird use of Winter-Flooded Rice Fields in the Sacramento Valley, California
Bird and habitat surveys were conducted in winter-flooded rice fields in the Sacramento Valley, California, USA during the fall and winters of 2021-2022 (Oct 2021 through February 2022) and 2022-2023 (December 2022 through February 2023). Rice field sampling consisted of (1) a bird survey that was followed by (2) an overall habitat assessment and (3) a more detailed habitat transect...
By
Western Ecological Research Center (WERC)
May 17, 2024
Duckling Survival in a Brackish Marsh
Duckling Survival in a Brackish Marsh
We conducted a multi-year study (2016-2019) to quantify sources of duckling mortality, identify predator type, and estimate survival rates for Mallard (Anas platyrhynchos) and Gadwall (Mareca strepera) ducklings within Suisun Marsh, California.
By
Western Ecological Research Center (WERC)
April 29, 2024
Methylmercury Effects on Birds: Bibliography and Dataset for the Development of Toxicity Reference Values for Injury Assessment
Methylmercury Effects on Birds: Bibliography and Dataset for the Development of Toxicity Reference Values for Injury Assessment
This data release contains three files. The first (Table S1 Bibliography Dataset) contains the entire bibliography for the 435 publications examined for potential inclusion into at least one of the meta-analyses for the effects of environmental mercury (Hg) on birds. For those 168 publications that were included in at least one meta-analysis, the worksheet titled Bibliography contains...
By
Western Ecological Research Center (WERC)
February 20, 2024
Egg Membrane Thickness in 13 Waterbird Species
Egg Membrane Thickness in 13 Waterbird Species
Eggshells of 13 waterbird species were divided in half longitudinally and the outer eggshell membrane was removed from one of the halves. Eggshell thickness was measured for both eggshell halves, both with and without the outer eggshell membrane. The eggshell membrane thickness was calculated by taking the difference between the two thickness measurements. These data support the...
By
Western Ecological Research Center (WERC)
February 7, 2024
Maternal Transfer of Mercury to Northern Elephant Seal Pups
Maternal Transfer of Mercury to Northern Elephant Seal Pups
We used free-ranging northern elephant seals as a model species to investigate maternal transfer of mercury (Hg) to pups in relation to maternal traits, including maternal blood mercury concentrations, and to quantify the links between pup lanugo mercury concentrations and maternal mesopelagic foraging behavior during gestation. We satellite tracked known-age adult females at sea during...
By
Western Ecological Research Center (WERC)
January 26, 2024
Eggshell Thickness in 5 Songbird Species
Eggshell Thickness in 5 Songbird Species
Eggshell thickness was measured at the egg equator and sharp pole for 5 songbird species. Each egg has thickness measurements at two locations on the egg and the corresponding egg length, egg width, egg volume, relative incubation age, egg identification, and nest identification. These data support the following publication: Schacter, C.R., Peterson, S.H., Hartman, C.A., Herzog, M.P...
By
Western Ecological Research Center (WERC)
April 5, 2023
Mercury, Cortisol, and Blood Biomarkers in Adult Female Northern Elephant Seals from 2011 to 2021
Mercury, Cortisol, and Blood Biomarkers in Adult Female Northern Elephant Seals from 2011 to 2021
This dataset represents 179 unique adult female northern elephant seals that were sampled between 2011 and 2021 during four different life history states (early breeding, late breeding, early molting, and late molting) at the Ano Nuevo colony in California, USA. Some individual seals were sampled multiple times, resulting in a total of 313 tissue samples. Tissue samples were collected...
By
Western Ecological Research Center (WERC)
September 20, 2022
Predator Movements and Duck Nests in Relation to Habitat Features in Suisun Marsh, CA (2016-2019)
Predator Movements and Duck Nests in Relation to Habitat Features in Suisun Marsh, CA (2016-2019)
This dataset describes mesopredator locations (raccoons and striped skunks), dabbling duck nest locations (mallard, gadwall, and cinnamon teal), northern harrier nest locations, and random locations in relation to a set of habitat features in Suisun Marsh, California during 2016 through 2019. We designed a series of questions to link fine-scale predator movements and vulnerability of...
By
Western Ecological Research Center (WERC)
August 17, 2022
Data measuring avian influenza infection, mercury concentration, and body condition in wild waterfowl
Data measuring avian influenza infection, mercury concentration, and body condition in wild waterfowl
These data represent mercury contamination, influenza infection, and body condition in 11 species of dabbling and diving ducks in the Pacific Flyway. These data support a USGS lead scientific publication.
By
Eastern Ecological Science Center
February 23, 2022
Nocturnal Incubation Recess and Flushing Behavior by Duck Hens Nesting in Grizzly Island Wildlife Area 2015-2018
Nocturnal Incubation Recess and Flushing Behavior by Duck Hens Nesting in Grizzly Island Wildlife Area 2015-2018
This dataset describes nocturnal incubation recess behavior for mallard and gadwall hens nesting in Grizzly Island Wildlife Area in breeding seasons 2015-2018. It includes the frequency, start time and duration of recesses, and details a method for determining whether a recess was initiated in response to a predator at the nest using nest temperature data. These data support the...
By
Western Ecological Research Center (WERC)
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
February 2, 2018
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
USGS scientist holds a young skunk with an ear tag ID and a lightweight GPS collar. The USGS is studying the movement patterns of skunks and raccoons in Suisun Marsh, CA to learn how they use different landscape features, like levee roads, to navigate to waterfowl nests.
By
Western Ecological Research Center (WERC)
February 2, 2018
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
Young Skunk with GPS Collar, WERC
USGS scientist holds a young skunk with an ear tag ID and a lightweight GPS collar. The USGS is studying the movement patterns of skunks and raccoons in Suisun Marsh, CA to learn how they use different landscape features, like levee roads, to navigate to waterfowl nests.
By
Western Ecological Research Center (WERC)
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
February 25, 2017
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
USGS field scientist uses radio telemetry to search for skunks and raccoons tagged with lightweight radio collars. USGS is monitoring skunk and raccoon movements across California's inland marshes to understand how they are using different features of the landscape, like levee roads, to navigate to waterfowl nests.
By
Western Ecological Research Center (WERC)
February 25, 2017
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
WERC Scientist Searches for Waterfowl Predators
USGS field scientist uses radio telemetry to search for skunks and raccoons tagged with lightweight radio collars. USGS is monitoring skunk and raccoon movements across California's inland marshes to understand how they are using different features of the landscape, like levee roads, to navigate to waterfowl nests.
By
Western Ecological Research Center (WERC)
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
July 1, 2016
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Photo of a skunk with an ear tag ID. Scientists from the USGS Western Ecological Research Center are studying the movements of skunks and raccoons within Suisun Marsh, CA to understand how they navigate the marsh to reach waterfowl nests. Results will inform the management of waterfowl populations within the Central Valley, CA.
By
Western Ecological Research Center (WERC)
July 1, 2016
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Young Skunk with Ear Tag ID
Photo of a skunk with an ear tag ID. Scientists from the USGS Western Ecological Research Center are studying the movements of skunks and raccoons within Suisun Marsh, CA to understand how they navigate the marsh to reach waterfowl nests. Results will inform the management of waterfowl populations within the Central Valley, CA.
By
Western Ecological Research Center (WERC)
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
June 8, 2016
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA.
By
Western Ecological Research Center (WERC)
June 8, 2016
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA
Hen in Suisun Marsh, CA.
By
Western Ecological Research Center (WERC)
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
May 23, 2016
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall ducklings in nest, Suisun Marsh, CA.
By
Western Ecological Research Center (WERC)
May 23, 2016
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall Ducklings in Nest
Gadwall ducklings in nest, Suisun Marsh, CA.
By
Western Ecological Research Center (WERC)
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
April 13, 2016
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS biological science technician Andrew Greenawalt holding a duckling with a lightweight radio transmitter. The USGS Western Ecological Research Center is monitoring waterfowl populations throughout Suisun Marsh, CA, and the greater Pacific Flyway. Radio transmitters fall off within several weeks and are recovered by scientists for data collection.
By
Western Ecological Research Center (WERC)
April 13, 2016
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS WERC Scientist with Duckling & Transmitter
USGS biological science technician Andrew Greenawalt holding a duckling with a lightweight radio transmitter. The USGS Western Ecological Research Center is monitoring waterfowl populations throughout Suisun Marsh, CA, and the greater Pacific Flyway. Radio transmitters fall off within several weeks and are recovered by scientists for data collection.
By
Western Ecological Research Center (WERC)
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
February 5, 2011
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male northern elephant seal (
Mirounga angustirostris
) resting on a sandy beach along the coast of California.
By
Western Ecological Research Center (WERC)
February 5, 2011
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male Northern Elephant Seal (Mirounga angustirostris)
Male northern elephant seal (
Mirounga angustirostris
) resting on a sandy beach along the coast of California.
By
Western Ecological Research Center (WERC)
Filter Total Items: 38
September 18, 2025
Habitat features influencing waterbird use of managed wetlands enrolled in a public-private partnership for land conservation: The California Waterfowl Habitat Program
Habitat features influencing waterbird use of managed wetlands enrolled in a public-private partnership for land conservation: The California Waterfowl Habitat Program
Draining, water diversion, and development have greatly reduced the availability of freshwater wetland habitat around the world, and many remaining wetlands are on private lands. Public–private partnership programs can be an important means for promoting habitat conservation and management on private lands. We investigated bird use of 117 wetlands enrolled in the California Waterfowl...
Authors
C. Alex Hartman, Joshua T. Ackerman, Sarah H. Peterson, Brady Lynn Fettig, Mark P. Herzog
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
November 20, 2024
Bird habitat value and management priorities of the California Winter Rice Habitat Incentive Program
Bird habitat value and management priorities of the California Winter Rice Habitat Incentive Program
Flooding rice (Oryza sativa) agricultural fields during winter to facilitate rice straw decomposition has mitigated the loss of some of the natural wetlands in California’s Central Valley. We conducted bird surveys in 253 rice checks (2,158 ha) within 177 rice fields in the Sacramento Valley during the fall and winter of 2021-2022 and 2022-2023 to evaluate factors influencing bird use of...
Authors
Sarah H. Peterson, Joshua T. Ackerman, Carley R. Schacter, C. Alex Hartman, Mark P. Herzog
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
August 12, 2024
Body mass changes of dabbling and diving ducks wintering in California
Body mass changes of dabbling and diving ducks wintering in California
Bird body mass is often used as an index of body condition and fluctuates throughout the year in response to environmental conditions and avian life-history events. We examined the body mass of 59,572 ducks representing 13 species (7 dabbling duck species and 6 diving duck species) harvested within the 3 regions of the Central Valley in California, USA (Sacramento Valley, Suisun Marsh...
Authors
Mark P. Herzog, Joshua T. Ackerman, Jeffrey D. Kohl, Brady Lynn Fettig, C. Alex Hartman, Sarah H. Peterson, Michael L. Casazza, Joseph P. Fleskes
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
May 13, 2024
Duckling survival increased with availability of flooded wetland habitat and decreased with salinity concentrations in a brackish marsh
Duckling survival increased with availability of flooded wetland habitat and decreased with salinity concentrations in a brackish marsh
Waterfowl population recruitment is sensitive to duckling survival. We quantified predator types and survival rates for Anas platyrhynchos (Mallard) and Mareca strepera (Gadwall) ducklings in one of the largest brackish water marshes in western North America (Suisun Marsh, California) using 556 radio-tagged ducklings from 284 broods tracked during the 2016 to 2019 breeding seasons...
Authors
Sarah H. Peterson, Joshua T. Ackerman, C. Alex Hartman, Andrew C. Greenawalt, Michael L. Casazza, Mark P. Herzog
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
April 29, 2024
Methylmercury effects on birds: A review, meta-analysis, and development of toxicity reference values for injury assessment based on tissue residues and diet
Methylmercury effects on birds: A review, meta-analysis, and development of toxicity reference values for injury assessment based on tissue residues and diet
Birds are used as bioindicators of environmental mercury (Hg) contamination, and toxicity reference values are needed for injury assessments. We conducted a comprehensive review, summarized data from 168 studies, performed a series of Bayesian hierarchical meta-analyses, and developed new toxicity reference values for the effects of methylmercury (MeHg) on birds using a benchmark dose...
Authors
Joshua T. Ackerman, Sarah H. Peterson, Mark P. Herzog, Julie L. Yee
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
April 24, 2024
Eggshell membrane thickness and its contribution to total eggshell thickness for 13 waterbird species
Eggshell membrane thickness and its contribution to total eggshell thickness for 13 waterbird species
Eggshell thickness can be an indicator of environmental pollution in wild birds and shell quality in wild and domestic birds, but it is difficult to measure calcite eggshell thickness due to the presence of the adherent outer eggshell membrane. Eggshells of 13 waterbird species were divided in half longitudinally and the outer membrane was removed from one of the halves. Subsequently, we...
Authors
Gary M. Santolo, Sarah H. Peterson, Breanne Cooney, C. Alex Hartman, Mark P. Herzog, Joshua T. Ackerman
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
February 26, 2024
Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups
Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups
Deep ocean foraging northern elephant seals (Mirounga angustirostris) consume fish and squid in remote depths of the North Pacific Ocean. Contaminants bioaccumulated from prey are subsequently transferred by adult females to pups during gestation and lactation, linking pups to mercury contamination in mesopelagic food webs (200–1000 m depths). Maternal transfer of mercury to developing...
Authors
Sarah H. Peterson, Michael G. Peterson, Joshua T. Ackerman, Cathy Debier, Chandra Goetsch, Rachel R. Holser, Luis A. Huckstadt, Jennifer C. Johnson, Theresa R. Keates, Birgitte I. McDonald, Elizabeth A. McHuron, Daniel P. Costa
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
January 31, 2024
Eggshell thickness and egg morphometrics in five songbird species from the Central Valley, California
Eggshell thickness and egg morphometrics in five songbird species from the Central Valley, California
Avian eggshell thickness is an important life history metric in birds and has broad applications across disciplines ranging from animal behavior to toxicology. Empirical eggshell thickness values for songbirds (Order Passeriformes) are under-represented in the literature due to the difficulty of measuring smaller eggs using traditional methods. We used a Hall-effect thickness gauge to...
Authors
Carley R. Schacter, Sarah H. Peterson, C. Alex Hartman, Mark P. Herzog, Joshua T. Ackerman
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
May 19, 2023
Nest attendance, incubation constancy, and onset of incubation in dabbling ducks
Nest attendance, incubation constancy, and onset of incubation in dabbling ducks
In birds, parents must provide their eggs with a safe thermal environment suitable for embryonic development. Species with uniparental incubation must balance time spent incubating eggs with time spent away from the nest to satisfy self-maintenance needs. Patterns of nest attendance, therefore, influence embryonic development and the time it takes for eggs to hatch. We studied nest...
Authors
C. Alex Hartman, Joshua T. Ackerman, Sarah H. Peterson, Brady Lynn Fettig, Michael L. Casazza, Mark P. Herzog
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
April 1, 2023
Habitat use by breeding waterbirds in relation to tidal marsh restoration in the San Francisco Bay estuary
Habitat use by breeding waterbirds in relation to tidal marsh restoration in the San Francisco Bay estuary
The South Bay Salt Pond Restoration Project aims to restore many former salt production ponds, now managed for wildlife and water quality, to tidal marsh. However, because managed ponds support large densities of breeding waterbirds, reduction of pond habitat may influence breeding waterbird distribution and abundance. We investigated habitat use associated with breeding, feeding, and...
Authors
Carley Rose Schacter, C. Alex Hartman, Mark P. Herzog, Sarah H. Peterson, Max L. Tarjan, Yewei Wang, Cheryl Strong, Rachel Tertes, Neil Warnock, Joshua T. Ackerman
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
March 30, 2023
Mercury bioaccumulation and cortisol interact to influence endocrine and immune biomarkers in a free-ranging marine mammal
Mercury bioaccumulation and cortisol interact to influence endocrine and immune biomarkers in a free-ranging marine mammal
Mercury bioaccumulation from deep-ocean prey and the extreme life history strategies of adult female northern elephant seals (Mirounga angustirostris) provide a unique system to assess the interactive effects of mercury and stress on animal health by quantifying blood biomarkers in relation to mercury (skeletal muscle and blood mercury) and cortisol concentrations. The thyroid hormone...
Authors
Sarah H. Peterson, Joshua T. Ackerman, Rachel R. Holser, Birgitte I. McDonald, Daniel P. Costa, Daniel E. Crocker
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
November 11, 2022
Dabbling duck eggs hatch after nest abandonment in the wild
Dabbling duck eggs hatch after nest abandonment in the wild
In most birds, parental incubation of eggs is necessary for embryo development and survival. Using a combination of weekly nest visits, temperature dataloggers, infrared video cameras, and GPS tracking of hens, we documented several instances of duck eggs hatching after being abandoned by the incubating female. Of 2826 Mallard (Anas platyrhynchos) and Gadwall (Mareca strepera) nests...
Authors
Carley Rose Schacter, Brady Lynn Fettig, Sarah H. Peterson, C. Alex Hartman, Mark P. Herzog, Michael L. Casazza, Joshua T. Ackerman
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
February 26, 2021
Waterfowl Ecology in Suisun Marsh and the Pacific Flyway
Waterfowl Ecology in Suisun Marsh and the Pacific Flyway
Learn about waterfowl research by scientists at the USGS Western Ecological Research Center.
By
Ecosystems Mission Area
Western Ecological Research Center (WERC)
San Francisco Bay and Sacramento-San Joaquin Delta Estuary
April 29, 2024
Methylmercury Effects on Birds: Percent Injury Tool
Methylmercury Effects on Birds: Percent Injury Tool
Welcome to The Bird Mercury Tool website. Please follow the guidance below to download the tool and user guide. The Bird Mercury Tool: Estimating Methylmercury Injury to Birds can be used by practitioners to help interpret injury to birds caused by methylmercury concentrations in bird tissues or diet. The dataset, statistical models, and assumptions used within this tool have been...
By
Western Ecological Research Center (WERC)
Helping the California Winter Rice Habitat Incentive Program increase bird use of winter-flooded rice fields
December 29, 2025
Helping the California Winter Rice Habitat Incentive Program increase bird use of winter-flooded rice fields
The Central Valley of California provides important habitat for waterbirds (waterfowl, shorebirds, and wading birds).
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Duckling survival is higher if nests are closer to wetland habitats flooded during the summer
December 29, 2025
Duckling survival is higher if nests are closer to wetland habitats flooded during the summer
A recent USGS study, in collaboration with the California Department of Fish and Wildlife at the Grizzly Island Wildlife Area, investigates what type...
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Re-establishing Waterbird Breeding Colonies in San Francisco Bay
April 17, 2024
Re-establishing Waterbird Breeding Colonies in San Francisco Bay
Learn more about how our partners are using ​science and management to maintain and establish new ​bird ​nesting colonies in support of the South Bay...
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Research Spotlight: What Habitat Features Make Duck Nests Vulnerable to Raccoons and Striped Skunks?
April 20, 2023
Research Spotlight: What Habitat Features Make Duck Nests Vulnerable to Raccoons and Striped Skunks?
Research by USGS scientists finds that predator-specific behaviors can shape where duck nests are most vulnerable in Suisun Marsh, CA. The findings...
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Research Spotlight: High Salinity and Limited Wetlands Reduce Duckling Habitat for Waterfowl
October 5, 2021
Research Spotlight: High Salinity and Limited Wetlands Reduce Duckling Habitat for Waterfowl
A new publication by USGS scientists examines wetland availability and salinity in Suisun Marsh, with particular focus on the implications for young...
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Research Spotlight: New Study Explores Nocturnal Nest Breaks and Predation Events for Dabbling Ducks
August 18, 2021
Research Spotlight: New Study Explores Nocturnal Nest Breaks and Predation Events for Dabbling Ducks
A new study by USGS scientists, in collaboration with the California Department of Water Resources and California Department of Fish and Wildlife...
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Research Spotlight: Precise Eggshell Thickness Measurements To Inform Bird Ecology And Mercury Monitoring
February 10, 2021
Research Spotlight: Precise Eggshell Thickness Measurements To Inform Bird Ecology And Mercury Monitoring
In a study published in the journal Ecology and Evolution, USGS biologists provide precise eggshell thickness measurements for 12 species of birds...
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Research Spotlight: Wetland Habitats and Aquatic Prey May Drive High Hair Mercury Concentrations in Suisun Marsh Raccoons
February 3, 2021
Research Spotlight: Wetland Habitats and Aquatic Prey May Drive High Hair Mercury Concentrations in Suisun Marsh Raccoons
A new study by scientists from USGS in collaboration with the California Department of Water Resources has found that mercury concentrations detected...
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Research Spotlight: Ducklings Leave Nests in Early Morning, Suggesting Predator Avoidance
June 12, 2019
Research Spotlight: Ducklings Leave Nests in Early Morning, Suggesting Predator Avoidance
In a study published in the journal Ecology and Evolution, U.S. Geological Survey (USGS) biologists put small cameras next to duck nests to determine...
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Research Spotlight: New Guidelines and Tool for Assessing Mercury Contamination Using Bird Feathers
May 31, 2019
Research Spotlight: New Guidelines and Tool for Assessing Mercury Contamination Using Bird Feathers
In a study published in the journal Environmental Toxicology and Chemistry, U.S. Geological Survey (USGS) biologists provide a detailed approach and...
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