Mike Casazza's research program at the Dixon Field Station focuses on the ecology of waterfowl and wetland management in the Pacific Flyway.
Mike and his team are experts in wildlife telemetry and apply cutting edge tools to answer complex ecological questions. In addition, Mike’s program also focuses on threatened and endangered species in a variety of ecosystems including primary ecological research on the endangered California Ridgway's Rail in SF Bay, the endangered San Francisco Gartersnake, the threatened Giant Gartersnake in the Central Valley of California, the California state-listed Greater Sandhill Crane, and the Greater Sage-Grouse. Mike Casazza's research has targeted studies which provide critical species information to land managers responsible for maintaining diverse and healthy wildlife populations while trying to help recover special status species. Understanding key life history traits of special status species can lead to management options promoting species recovery.
- 1995 M.S. California State University, Sacramento Thesis: Habitat use and movement of Northern Pintails wintering in Suisun Marsh, CA
- 1988 B.S. Wildlife Biology, U.C. Davis
Science and Products
Avian Influenza Prevalence Correlated to Mercury Concentrations in Wild Waterfowl
Goose Population Dynamics in the California Central Valley and Pacific Flyway
Webinar: Linking Remote Sensing and Bird Behavior Data to Understand the Impacts of Drought on Waterfowl
Suisun Marsh Waterfowl and Wildlife Studies
Waterfowl Ecology in California and the Pacific Flyway
Ecology and Population Dynamics of Ridgway's Rails along the West Coast of the U.S.
Dixon Field Station
The Impact of Drought on Waterbirds and Their Wetland Habitats in California’s Central Valley
Effects of Sea-Level Rise and Extreme Storms on California Coastal Habitats: Part 1
Fate of Endangered Species in San Francisco Bay Tidal Marshes with Sea-Level Rise
Influence of microhabitat characteristics on sage-grouse nest site selection and nest survival depends on ecological site potential
Selection and Survival of Greater Sage-Grouse Broods in Mesic Areas of Long Valley, California (2003 - 2018)
Data describing infection status and movement ecology of North American waterfowl
Spatially-Explicit Predictive Maps of Greater Sage-Grouse Brood Selection Integrated with Brood Survival in Nevada and Northeastern California, USA
Hourly GPS Locations, Associated Habitat Condition, and Annotated Life History State for Training Machine Learned Models of Waterfowl Daily Activity
Data measuring avian influenza infection, mercury concentration, and body condition in wild waterfowl
Selenium concentrations in Yuma Ridgway's Rails occupying managed and unmanaged emergent marshes at the Salton Sea
Yuma Ridgway's Rail (Rallus obsoletus yumanensis) Population Surveys, Rail Movement, and Potential Habitat at the Salton Sea of California
Suisun Tidal Marsh Duck Use Dataset
Migration stopover ecology of cinnamon teal in western North America
Waterfowl Disturbance in California and Nevada (2018)
Locations of Pacific Flyway Ducks in and near Commercial Livestock Facilities of the Western USA (2015-2021)
Nest attendance, incubation constancy, and onset of incubation in dabbling ducks
Knowledge coproduction on the impact of decisions for waterbird habitat in a changing climate
Geothermal energy production adversely affects a sensitive indicator species within sagebrush ecosystems in western North America
Waterfowl recently infected with low pathogenic avian influenza exhibit reduced local movement and delayed migration
Influence of fine-scale habitat characteristics on sage-grouse nest site selection and nest survival varies by mesic and xeric site conditions
Changes in habitat suitability for wintering dabbling ducks during dry conditions in the Central Valley of California
Moisture abundance and proximity mediate seasonal use of mesic areas and survival of greater sage-grouse broods
Dabbling duck eggs hatch after nest abandonment in the wild
Postbreeding movements and molting ecology of female gadwalls and mallards
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
Spatiotemporal changes in influenza A virus prevalence among wild waterfowl inhabiting the continental United States throughout the annual cycle
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
Avian Influenza Prevalence Correlated to Mercury Concentrations in Wild WaterfowlLow pathogenic avian influenza infections were directly correlated with blood mercury concentrations in wild waterfowl, indicating that mercury exposure may be related to pathogen susceptibility. Further study is needed to determine if and how mercury and other environmental contaminant exposures may affect disease susceptibility in wildlife.
Goose Population Dynamics in the California Central Valley and Pacific FlywayUSGS scientists and partners are studying how growing goose populations in the California Central Valley wintering areas are affecting ducks and other waterfowl.
Webinar: Linking Remote Sensing and Bird Behavior Data to Understand the Impacts of Drought on WaterfowlView this webinar to learn how scientists are exploring the impacts of drought on waterfowl.
Suisun Marsh Waterfowl and Wildlife StudiesSuisun Marsh provides critical habitat for wintering and breeding waterbirds in California. USGS WERC collaborates with the California Department of Water Resources to examine trends in bird declines and to assess the habitat factors driving long-term survival of waterfowl, rails, and other birds in this important area.
Waterfowl Ecology in California and the Pacific FlywayThe Suisun Marsh and Central Valley in California offer some of the world’s most important wetland habitats for waterfowl in the Pacific Flyway. Mike Casazza and USGS WERC biologists are providing the science to support and evaluate waterfowl populations and habitat management in North America.
Ecology and Population Dynamics of Ridgway's Rails along the West Coast of the U.S.The Ridgway’s rail is a federal and state listed endangered species that occurs in wetlands along the Pacific Coast and from the Lower Colorado River drainage to southern Baja California. Three subspecies of Ridgway’s rail are found within the United States: the California Ridgway’s Rail, Yuma Ridgway’s rail, and Light-footed Ridgway’s rail. All three subspecies have declined since 1900 as a...
Dixon Field StationWERC scientists at the Dixon Field Station conduct studies from the San Francisco Bay-Delta in California to the Great Basin spanning California and Nevada.
The Impact of Drought on Waterbirds and Their Wetland Habitats in California’s Central ValleyCalifornia’s Central Valley is a nexus for water resources in the state, draining the Sacramento and San Joaquin River watersheds. Urban centers, agricultural operations, and the environment all compete for limited water, and demand is expected to only increase as the population grows and agriculture intensifies. At the same time, the water supply is projected to decrease as temperatures rise, pre...
Effects of Sea-Level Rise and Extreme Storms on California Coastal Habitats: Part 1In California, the near-shore area where the ocean meets the land is a highly productive yet sensitive region that supports a wealth of wildlife, including several native bird species. These saltmarshes, mudflats, and shallow bays are not only critical for wildlife, but they also provide economic and recreational benefits to local communities. Today, sea-level rise, more frequent and stronger stor
Fate of Endangered Species in San Francisco Bay Tidal Marshes with Sea-Level RiseThe San Francisco Bay estuary contains the largest remaining expanse of tidal salt marshes in the western U.S. These marshes are home to a variety of federal and state protected species, such as the California clapper rail, California black rail, and the salt marsh harvest mouse. The estuary is also located on the Pacific Flyway, and is an important site for migrating and wintering birds. As clima
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Influence of microhabitat characteristics on sage-grouse nest site selection and nest survival depends on ecological site potentialWe examined nest survival of Greater Sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) in relation to fine-scale habitat patterns that influenced nest site selection, using data from nests of telemetered females at 17 sites across 6 years in Nevada and northeastern California, USA. Importantly, sites spanned mesic and xeric average precipitation conditions and concomitant vegetation
Selection and Survival of Greater Sage-Grouse Broods in Mesic Areas of Long Valley, California (2003 - 2018)We evaluated brood-rearing habitat selection and brood survival of greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) in Long Valley, California, an area where the water rights are primarily owned by the city of Los Angeles and water is used locally to irrigate for livestock. This area thus represents a unique balance between the needs of wildlife and people that could increas
Data describing infection status and movement ecology of North American waterfowlThese data, which support a USGS authored manuscript, describe how active and previous previous infection with avian influenza impacts the movement ecology of several wild waterfowl species that overwinter in California. Results varied by species and demonstrate that the relationships between avian influenza infection and wild bird movements are context- and species-dependent.
Spatially-Explicit Predictive Maps of Greater Sage-Grouse Brood Selection Integrated with Brood Survival in Nevada and Northeastern California, USAWe used a hierarchical Bayesian modeling framework to estimate resource selection functions and survival for early and late brood-rearing stages of sage-grouse in relation to a broad suite of habitat characteristics evaluated at multiple spatial scales within the Great Basin from 2009 to 2019. Sage-grouse selected for greater perennial grass cover, higher relative elevations, and areas closer to s
Hourly GPS Locations, Associated Habitat Condition, and Annotated Life History State for Training Machine Learned Models of Waterfowl Daily ActivityThese data represent an annotated training data for machine learned life history classification of the daily activity of dabbling ducks (f. Anatidae sf. Anatinae) using hourly GPS data. Each row of data represents a single GPS location for one of 5 species of dabbling duck. Note: the machine learned model was developed to be general across sf. Anatinae and does not include specific reference to th
Data measuring avian influenza infection, mercury concentration, and body condition in wild waterfowlThese 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.
Selenium concentrations in Yuma Ridgway's Rails occupying managed and unmanaged emergent marshes at the Salton SeaYuma Ridgway's rail (Rallus obsoletus yumanensis, hereafter, "rail" are an endangered species for which patches of emergent marsh within the Salton Sea watershed comprise a substantial portion of habitat for the species' disjointed range in the southwestern United States. These areas of emergent marsh include: 1) marshes managed by federal (particularly the U.S. Fish and Wildlife Service's Sonny B
Yuma Ridgway's Rail (Rallus obsoletus yumanensis) Population Surveys, Rail Movement, and Potential Habitat at the Salton Sea of CaliforniaData were obtained as part of a project assessing risk to the federal and California listed endangered Yuma Ridgway's rail (Rallus obsoletus yumanensis) populations resulting from selenium contaminated agricultural runoff and to inform habitat restoration and management decisions. Four data sets were produced and used to analyze patterns of Yuma Ridgway's rail (Rallus obsoletus yumanensis, renamed
Suisun Tidal Marsh Duck Use DatasetLocation data with corresponding habitat class (managed vs tidal marsh) and habitat type (permanent pond, seasonal pond, channel, or marshland) for waterfowl utilizing the Suisun Marsh region of California with species, sex, season and date information. These data support the following publication: Casazza, M.L., McDuie, F., Jones, S., Lorenz, A.A., Overton, C.T., Yee, J., Feldheim, C.L., Acke
Migration stopover ecology of cinnamon teal in western North AmericaIdentifying migration routes and fall stopover sites of cinnamon teal (Spatula cyanoptera septentrionalium) can provide a spatial guide to management and conservation efforts, and address vulnerabilities in wetland networks that support migratory waterbirds. Using high spatio-temporal resolution GSM-GPS transmitters, we tracked the fall migration of 61 cinnamon teal across western North America ov
Waterfowl Disturbance in California and Nevada (2018)Long-term environmental management to prevent waterfowl population declines is informed by ecology, movement behavior and habitat use patterns. Extrinsic factors such as human-induced disturbance can cause behavioral changes which may influence movement, and resource needs, driving variation that affects management efficacy. To better understand the relationship between human-based disturbance and
Locations of Pacific Flyway Ducks in and near Commercial Livestock Facilities of the Western USA (2015-2021)Zoonotic diseases are of considerable concern to the human population and viruses such as avian influenza (AIV) threaten food security, wildlife conservation and human health. Wild waterfowl and the natural wetlands they use, are known AIV reservoirs, with birds capable of virus transmission to domestic poultry populations. While infection risk models have linked migration routes and AIV outbreaks
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Nest attendance, incubation constancy, and onset of incubation in dabbling ducksIn 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. Herzog
Knowledge coproduction on the impact of decisions for waterbird habitat in a changing climateScientists, resource managers, and decision-makers increasingly use knowledge co-production to guide the stewardship of future landscapes under climate change. This process was applied in the California Central Valley, USA to solve complex conservation problems, where managed wetlands and croplands are flooded between fall and spring to support some of the largest concentrations of shorebirds andAuthorsKristin B. Byrd, Elliott Matchett, Claudia Mengelt, Tamara S. Wilson, Deanne DiPietro, Monica Moritsch, Erin Conlisk, Sam Veloz, Michael L. Casazza, Matthew Reiter
Geothermal energy production adversely affects a sensitive indicator species within sagebrush ecosystems in western North AmericaGrowing demand for renewable energy has resulted in expansion of energy infrastructure across sagebrush ecosystems of western North America. Geothermal power is an increasingly popular renewable energy source, especially within remote areas, but little is known about the impacts it may have on local wildlife populations. Investigations are warranted given similarities to more conventional surfaceAuthorsPeter S. Coates, Brian G. Prochazka, Shawn O'Neil, Sarah Catherine Webster, Shawn Espinosa, Mark A. Ricca, Steven R. Mathews, Michael L. Casazza, David J. Delehanty
Waterfowl recently infected with low pathogenic avian influenza exhibit reduced local movement and delayed migrationUnderstanding relationships between infection and wildlife movement patterns is important for predicting pathogen spread, especially for multispecies pathogens and those that can spread to humans and domestic animals, such as avian influenza viruses (AIVs). Although infection with low pathogenic AIVs is generally considered asymptomatic in wild birds, prior work has shown that influenza-infected bAuthorsClaire S. Teitelbaum, Michael L. Casazza, Fiona McDuie, Susan E. W. De La Cruz, Cory T. Overton, Laurie Anne Hall, Elliott Matchett, Josh T. Ackerman, Jeffery D. Sullivan, Andrew M. Ramey, Diann Prosser
Influence of fine-scale habitat characteristics on sage-grouse nest site selection and nest survival varies by mesic and xeric site conditionsResource managers and scientists across western U.S. agencies seek methodologies for identifying environmental attributes important to both wildlife conservation and broad-scale land stewardship. The Greater Sage-Grouse (Centrocercus urophasianus; hereafter, sage-grouse) exemplifies a species in need of this broad-scale approach given widespread population declines that have resulted from loss andAuthorsBrianne E. Brussee, Peter S. Coates, Shawn O'Neil, Mark A. Ricca, Jonathan E. Dudko, Shawn P. Espinosa, Scott C. Gardner, Michael L. Casazza, David J. Delehanty
Changes in habitat suitability for wintering dabbling ducks during dry conditions in the Central Valley of CaliforniaIn arid and Mediterranean regions, landscape-scale wetland conservation requires understanding how wildlife responds to dynamic freshwater availability and conservation actions to enhance wetland habitat. Taking advantage of Landsat satellite data and structured and community science bird survey data, we built species distribution models to describe how three duck species, the Northern Pintail (AnAuthorsErin E. Conlisk, Kristin B. Byrd, Elliott Matchett, Austen Lorenz, Michael L. Casazza, Gregory H. Golet, Mark D. Reynolds, Kristin A. Sesser, Matthew E. Reiter
Moisture abundance and proximity mediate seasonal use of mesic areas and survival of greater sage-grouse broodsWater is a critical and limited resource, particularly in the arid West, but water availability is projected to decline even while demand increases due to growing human populations and increases in duration and severity of drought. Mesic areas provide important water resources for numerous wildlife species, including the greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse), an iAuthorsJohn P. Severson, Peter S. Coates, Megan Cochran Milligan, Shawn O'Neil, Mark A. Ricca, Steve C. Abele, John D. Boone, Michael L. Casazza
Dabbling duck eggs hatch after nest abandonment in the wildIn 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. Ackerman
Postbreeding movements and molting ecology of female gadwalls and mallardsThe wing molt is an important annual life-history event that occurs in waterfowl and molt site selection can play an important role in determining survival. We tracked postbreeding movements of gadwall (Mareca strepera) and mallard (Anas platyrhynchos) females that bred in the Suisun Marsh (Suisun) of California, USA, to determine molt site selection and wing molt chronology. We attached backpackAuthorsJeffrey D Kohl, Michael L. Casazza, Cory T. Overton, Mark P. Herzog, Josh T. Ackerman, Cliff L. Feldheim, John M. Eadie
Predator movements in relation to habitat features reveal vulnerability of duck nests to predationNest 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. Herzog
Avian influenza antibody prevalence increases with mercury contamination in wild waterfowlEnvironmental 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 Prosser
Spatiotemporal changes in influenza A virus prevalence among wild waterfowl inhabiting the continental United States throughout the annual cycleAvian influenza viruses can pose serious risks to agricultural production, human health, and wildlife. An understanding of viruses in wild reservoir species across time and space is important to informing surveillance programs, risk models, and potential population impacts for vulnerable species. Although it is recognized that influenza A virus prevalence peaks in reservoir waterfowl in late summeAuthorsCody M. Kent, Andrew M. Ramey, Josh T. Ackerman, Justin Bahl, Sarah N. Bevins, Andrew S. Bowman, Walter Boyce, Carol Cardona, Michael L. Casazza, Troy D. Cline, Susan E. W. De La Cruz, Jeffrey S. Hall, Nichola J. Hill, Hon S. Ip, Scott Krauss, Jennifer M. Mullinax, Jacqueline M. Nolting, Magdalena Plancarte, Rebecca L. Poulson, Jonathan A. Runstadler, Richard D. Slemons, David E. Stallknecht, Jeffery D. Sullivan, John Y. Takekawa, Richard J. Webby, Robert G. Webster, Diann J. Prosser
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Waterfowl Ecology in Suisun Marsh and the Pacific Flyway
Learn about waterfowl research by scientists at the USGS Western Ecological Research Center.