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.
Sarah Peterson
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
Egg Membrane Thickness in 13 Waterbird Species
Maternal Transfer of Mercury to Northern Elephant Seal Pups
Eggshell Thickness in 5 Songbird Species
Mercury, Cortisol, and Blood Biomarkers in Adult Female Northern Elephant Seals from 2011 to 2021
Predator Movements and Duck Nests in Relation to Habitat Features in Suisun Marsh, CA (2016-2019)
Data measuring avian influenza infection, mercury concentration, and body condition in wild waterfowl
Nocturnal Incubation Recess and Flushing Behavior by Duck Hens Nesting in Grizzly Island Wildlife Area 2015-2018
Hair and blood total mercury concentrations in raccoons and striped skunks from Suisun Marsh 2016 to 2019
Avian Eggshell Thickness for 12 Species in the Western U.S. from 2014 to 2018
The timing of dabbling duckling hatch, nest departure and depredation in Suisun Marsh, California from 2015-2017
Variability of mercury concentrations among whole bird feathers, feather homogenates, and feather components quantified in California in 2017-2018
Prey fish returned to Forsters tern colonies in South San Francisco Bay during 2005-2015
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.
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.
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.
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.
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.
Mallard drake taking flight.
Mallard drake taking flight.
Hen in Suisun Marsh, CA.
Gadwall ducklings in nest, Suisun Marsh, CA.
Gadwall ducklings in nest, Suisun Marsh, CA.
Male northern elephant seal (Mirounga angustirostris) resting on a sandy beach along the coast of California.
Male northern elephant seal (Mirounga angustirostris) resting on a sandy beach along the coast of California.
Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups
Eggshell thickness and egg morphometrics in five songbird species from the Central Valley, California
Nest attendance, incubation constancy, and onset of incubation in dabbling ducks
Habitat use by breeding waterbirds in relation to tidal marsh restoration in the San Francisco Bay estuary
Dabbling duck eggs hatch after nest abandonment in the wild
Predator movements in relation to habitat features reveal vulnerability of duck nests to predation
Avian influenza antibody prevalence increases with mercury contamination in wild waterfowl
Wetland availability and salinity concentrations for breeding waterfowl in Suisun Marsh, California
Nocturnal incubation recess and flushing behavior by duck hens
Interrupted incubation: How dabbling ducks respond when flushed from the nest
Mercury exposure in mammalian mesopredators inhabiting a brackish marsh
Avian eggshell thickness in relation to egg morphometrics, embryonic development, and mercury contamination
Waterfowl Ecology in Suisun Marsh and the Pacific Flyway
Learn about waterfowl research by scientists at the USGS Western Ecological Research Center.
Science and Products
- Data
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.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 their seveEggshell 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., and AckermaMercury, 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 from seals aPredator 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 dabbling duckData 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.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 following pubHair and blood total mercury concentrations in raccoons and striped skunks from Suisun Marsh 2016 to 2019
Total mercury concentrations were determined in hair and whole blood of raccoons and skunks in Suisun Marsh from 2016 to 2019. Individual skunks and raccoons were identified by a unique identifier (Animal_ID) and some animals were sampled multiple times. This dataset includes animal sex, age class, the date the sample was collected, animal body mass, head length, and head-to-torso length. TheAvian Eggshell Thickness for 12 Species in the Western U.S. from 2014 to 2018
Eggshell thickness was measured at the egg equator and poles (sharp pole and blunt pole) for 12 avian species. Eggshell thickness was related to egg morphometrics (egg length and width), embryonic development, egg status, and mercury contamination. Individual eggshells each have up to 3 thickness measurements, linked by the eggshell identification. Each measurement has the corresponding egg lengthThe timing of dabbling duckling hatch, nest departure and depredation in Suisun Marsh, California from 2015-2017
These data include a row for each duck nest equipped with a small video camera. We present the location of the nest, the timing of the start of hatch, the timing of the end of hatch, and the timing of the departure of the hen and ducklings from the nest. Additionally, this table includes any predators that were observed at the nest depredating eggs prior to hatch and any predators that were observVariability of mercury concentrations among whole bird feathers, feather homogenates, and feather components quantified in California in 2017-2018
These data are the raw total mercury (THg) concentrations in whole feathers, feather homogenates, and feather components (i.e., rachis, vane, calamus) that are presented in the Journal Article "Mercury concentrations vary within and among individual bird feathers: A critical evaluation and guidelines for feather use in mercury monitoring programs" in Environmental Toxicology and Chemistry by PeterPrey fish returned to Forsters tern colonies in South San Francisco Bay during 2005-2015
Prey fish were collected at 17 Forsters tern breeding colonies during colony visits from 2005-2015. Prey fish were identified to the lowest taxonomic category. We present relative abundances by colony and year for each of the 10 major species groups. Unidentified fish species or rarely observed species were combined into an Other category. We calculated an arithmetic mean, standard deviation (sd), - Multimedia
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.
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.
WERC Scientist Searches for Waterfowl PredatorsUSGS 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.
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.
Young Skunk with Ear Tag IDPhoto 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.
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.
Mallard Drake Taking FlightMallard drake taking flight.
Mallard drake taking flight.
Hen in Suisun Marsh, CAHen in Suisun Marsh, CA.
Gadwall Ducklings in NestGadwall ducklings in nest, Suisun Marsh, CA.
Gadwall ducklings in nest, Suisun Marsh, CA.
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.
Male northern elephant seal (Mirounga angustirostris) resting on a sandy beach along the coast of California.
- Publications
Filter Total Items: 27
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 seal pups wAuthorsSarah H. Peterson, Michael G. Peterson, Josh T. Ackerman, Cathy Debier, Chandra Goetsch, Rachel R. Holser, Luis A. Hückstädt, Jennifer C. Johnson, Theresa R. Keates, Birgitte I. McDonald, Elizabeth A. McHuron, Daniel P. CostaEggshell 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 measure eggsAuthorsCarley R. Schacter, Sarah H. Peterson, C. Alex Hartman, Mark P. Herzog, Josh T. AckermanNest 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 attendance (timAuthorsC. Alex Hartman, Josh T. Ackerman, Sarah H. Peterson, Brady Lynn Fettig, Michael L. Casazza, Mark P. HerzogHabitat 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 roosting behAuthorsCarley Rose Schacter, C. Alex Hartman, Mark P. Herzog, Sarah H. Peterson, Max L. Tarjan, Yewei Wang, Cheryl Strong, Rachel Tertes, Neil Warnock, Josh T. AckermanDabbling 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 monitored 2015AuthorsCarley Rose Schacter, Brady Lynn Fettig, Sarah H. Peterson, C. Alex Hartman, Mark P. Herzog, Michael L. Casazza, Josh T. AckermanPredator movements in relation to habitat features reveal vulnerability of duck nests to predation
Nest predation is the main cause of nest failure for ducks. Understanding how habitat features influence predator movements may facilitate management of upland and wetland breeding habitats that reduces predator encounter rates with duck nests and increases nest survival rates. For 1618 duck nests, nest survival increased with distance to phragmites (Phragmites australis), shrubs, telephone poles,AuthorsSarah H. Peterson, Josh T. Ackerman, Meghan P Keating, Carley Rose Schacter, C. Alex Hartman, Michael L. Casazza, Mark P. HerzogAvian influenza antibody prevalence increases with mercury contamination in wild waterfowl
Environmental contamination is widespread and can negatively impact wildlife health. Some contaminants, including heavy metals, have immunosuppressive effects, but prior studies have rarely measured contamination and disease simultaneously, which limits our understanding of how contaminants and pathogens interact to influence wildlife health. Here, we measured mercury concentrations, influenza infAuthorsClaire Stewart Teitelbaum, Josh T. Ackerman, Mason A. Hill, Jaqueline M. Satter, Michael L. Casazza, Susan E. W. De La Cruz, Walter M. Boyce, Evan James Buck, John M. Eadie, Mark P. Herzog, Elliott Matchett, Cory T. Overton, Sarah H. Peterson, Magdalena Plancarte, Andrew M. Ramey, Jeffery D. Sullivan, Diann ProsserWetland availability and salinity concentrations for breeding waterfowl in Suisun Marsh, California
Availability of wetlands with low salinities during the breeding season can influence waterfowl reproductive success and population recruitment. Salinities as low as 2 ppt (3.6 mScm–1) can impair duckling growth and influence behavior, with mortality occurring above 9 ppt (14.8 mScm–1). We used satellite imagery to quantify the amount of available water, and sampled surface water salinity at GrizzAuthorsCarley Rose Schacter, Sarah H. Peterson, Mark P. Herzog, C. Alex Hartman, Michael L. Casazza, Josh T. AckermanNocturnal incubation recess and flushing behavior by duck hens
Incubating birds must balance the needs of their developing embryos with their own physiological needs, and many birds accomplish this by taking periodic breaks from incubation. Mallard (Anas platyrhynchos) and gadwall (Mareca strepera) hens typically take incubation recesses in the early morning and late afternoon, but recesses can also take place at night. We examined nocturnal incubation recessAuthorsRebecca Croston, Sarah H. Peterson, C. Alex Hartman, Mark P. Herzog, Cliff L. Feldheim, Michael L. Casazza, Josh T. AckermanInterrupted incubation: How dabbling ducks respond when flushed from the nest
Nesting birds must provide a thermal environment sufficient for egg development while also meeting self‐maintenance needs. Many birds, particularly those with uniparental incubation, achieve this balance through periodic incubation recesses, during which foraging and other self‐maintenance activities can occur. However, incubating birds may experience disturbances such as predator or human activitAuthorsRebecca Croston, C. Alex Hartman, Mark P. Herzog, Sarah H. Peterson, Jeffrey Kohl, Cory T. Overton, Cliff L. Feldheim, Michael L. Casazza, Josh T. AckermanMercury exposure in mammalian mesopredators inhabiting a brackish marsh
Bioaccumulation of environmental contaminants in mammalian predators can serve as an indicator of ecosystem health. We examined mercury concentrations of raccoons (Procyon lotor; n = 37 individuals) and striped skunks (Mephitis mephitis; n = 87 individuals) in Suisun Marsh, California, a large brackish marsh that is characterized by contiguous tracts of tidal marsh and seasonally impounded wetlandAuthorsSarah H. Peterson, Josh T. Ackerman, C. Alex Hartman, Michael L. Casazza, Cliff L. Feldheim, Mark P. HerzogAvian eggshell thickness in relation to egg morphometrics, embryonic development, and mercury contamination
Eggshell thickness is important for physiological, ecological, and ecotoxicological studies on birds; however, empirical eggshell thickness measurements for many species and regions are limited. We measured eggshell thickness at the equator and the egg poles for 12 avian species and related eggshell thickness to egg morphometrics, embryonic development, egg status, and mercury contamination. WithiAuthorsSarah H. Peterson, Josh T. Ackerman, Mark P. Herzog, Matthew Toney, Breanne Cooney, C. Alex Hartman - Web Tools
Waterfowl Ecology in Suisun Marsh and the Pacific Flyway
Learn about waterfowl research by scientists at the USGS Western Ecological Research Center.
- News