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Michael Casazza

Mike Casazza's research program at the Dixon Field Station focuses on the ecology of waterfowl and wetland management in the Pacific Flyway.

RESEARCH INTERESTS

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. 

EDUCATION 

  • 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

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Hands hold up brown goose wearing a brown GPS collar

Goose Population Dynamics in the California Central Valley and Pacific Flyway

USGS scientists and partners are studying how growing goose populations in the California Central Valley wintering areas are affecting ducks and other waterfowl.
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Western Ecological Research Center (WERC)
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Goose Population Dynamics in the California Central Valley and Pacific Flyway

USGS scientists and partners are studying how growing goose populations in the California Central Valley wintering areas are affecting ducks and other waterfowl.
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Dozens of birds flying over grassy wetlands

Webinar: Linking Remote Sensing and Bird Behavior Data to Understand the Impacts of Drought on Waterfowl

View this webinar to learn how scientists are exploring the impacts of drought on waterfowl.
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Southwest Climate Science Center, Climate Adaptation Science Center
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Webinar: Linking Remote Sensing and Bird Behavior Data to Understand the Impacts of Drought on Waterfowl

View this webinar to learn how scientists are exploring the impacts of drought on waterfowl.
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Mallard drake taking flight

Suisun Marsh Waterfowl and Wildlife Studies

Suisun 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.
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Western Ecological Research Center (WERC)
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Suisun Marsh Waterfowl and Wildlife Studies

Suisun 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.
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Photo of a hen pintail with a GPS transmitter.

Waterfowl Ecology in California and the Pacific Flyway

The 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.
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Ecosystems, Western Ecological Research Center (WERC)
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Waterfowl Ecology in California and the Pacific Flyway

The 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.
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WERC Ridgway’s rail in vegetation

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...
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Ecosystems, Western Ecological Research Center (WERC)
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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...
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Dozens of birds flying over grassy wetlands

The Impact of Drought on Waterbirds and Their Wetland Habitats in California’s Central Valley

California’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...
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Climate Adaptation Science Centers, Climate Adaptation Science Center
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The Impact of Drought on Waterbirds and Their Wetland Habitats in California’s Central Valley

California’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...
Learn More
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Dozens of birds flying over grassy wetlands

The Impact of Drought on Waterbirds and Their Wetland Habitats in California’s Central Valley

California’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...
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Climate Adaptation Science Centers, Climate Adaptation Science Center
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The Impact of Drought on Waterbirds and Their Wetland Habitats in California’s Central Valley

California’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...
Learn More
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color photograph of California coastal cliff

Effects of Sea-Level Rise and Extreme Storms on California Coastal Habitats: Part 1

In 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
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Climate Adaptation Science Centers, Climate Adaptation Science Center
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Effects of Sea-Level Rise and Extreme Storms on California Coastal Habitats: Part 1

In 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
Learn More
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color photograph of California coastal cliff

Effects of Sea-Level Rise and Extreme Storms on California Coastal Habitats: Part 1

In 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
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Climate Adaptation Science Centers, Climate Adaptation Science Center
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Effects of Sea-Level Rise and Extreme Storms on California Coastal Habitats: Part 1

In 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
Learn More
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Marsh with tall grasses and orange markers set out by scientists

Fate of Endangered Species in San Francisco Bay Tidal Marshes with Sea-Level Rise

The 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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Climate Adaptation Science Centers
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Fate of Endangered Species in San Francisco Bay Tidal Marshes with Sea-Level Rise

The 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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Tule greater white-fronted goose migration tracks (2019-2020) and atmospheric smoke concentrations (2020).

April through May (spring) and August through September (fall) locations for tule greater white-fronted geese (Anser albifrons elgasi) marked with GPS collars at Summer Lake Wildlife Area, OR in 2018 and 2019. Locations may include pre-migration and post-migration designations. Locations occurring between September 11, 2020, and arrival at, or within 50 kilometers of the Summer Lake Wildlife Area
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Western Ecological Research Center (WERC)

Tracking Data for Greater White-fronted Geese (Anser albifrons)

This metadata document describes VHF tracking data for Greater White-fronted Geese (Anser albifrons) that were marked annually from 1987 to 1991 in Alaska and the Klamath Basin (Oregon and California) and subsequently tracked through the Pacific Flyway (primarily in Alaska, California, and Mexico). Only tracking data for geese marked or located, at least once, in Alaska are included in this data p
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Alaska Science Center

Comparisons of Gambel's quail survey methods conducted in 2016 within the Mohave Desert of California with results and summaries

Data includes results collected in the Mohave Desert during 2016 using three survey methods (acoustic recording units, camera traps, and call-count surveys) to detect gamebirds, primarily Gambel's quail (Callipepla gambelii) but also including records of mourning dove (Zenaida macroura), Eurasian collared-dove (Streptopelia decaocto), and chukar (Alectoris chukar). ARU data includes the Selections
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Western Ecological Research Center (WERC)

Impounded and tidal wetland plant diversity and composition across spatial scales, San Francisco Bay-Delta, California, USA (2016-2018)

These datasets provide information on plant alpha, beta, and gamma diversity, and plant species abundance at several spatial scales for tidal wetlands along a salinity gradient in the San Francisco Bay-Delta and an impounded brackish wetland complex in Suisun Marsh, California. Files include diversity metrics calculated at the patch, site, and region scales, average percent cover of wetland domina
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Western Ecological Research Center (WERC)

Classification of waterfowl habitat, and quantification of interannual space use and movement distance from primary roosts to night feeding locations by waterfowl in California for October - March of 2015 through 2018

Technological advancements in Global Positioning System (GPS) telemetry markers allow almost real-time observation of waterfowl movements and habitat selection. Telemetry data on ducks marked with GPS transmitters can be used to evaluate performance of remote sensing data (for example, dynamic open-water maps produced by Point Blue Conservation Science) for classifying habitats that are flooded an
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Western Ecological Research Center (WERC)

Coastal California San Francisco Gartersnake Capture-Mark-Recapture Data (2008-2013)

These data are multi-state capture histories of 273 individual San Francisco gartersnakes collected at a site before and after a portion of the site was burned. Data collection began in 2008 and continued until 2013, and the prescribed fire was applied in the fall of 2010. These data support the following paper: Halstead, B. J., Thompson, M. E., Amarello, M. , Smith, J. J., Wylie, G. D., Routman,
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Western Ecological Research Center (WERC)

Geospatial data for object-based high-resolution classification of conifers within greater sage-grouse habitat across Nevada and a portion of northeastern California

These products were developed to provide scientific and correspondingly spatially explicit information regarding the distribution and abundance of conifers (namely, singleleaf pinyon (Pinus monophylla), Utah juniper (Juniperus osteosperma), and western juniper (Juniperus occidentalis)) in Nevada and portions of northeastern California. Encroachment of these trees into sagebrush ecosystems of the G
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Western Ecological Research Center (WERC)

Data for: A conservation planning tool for greater sage-grouse using indices of species distribution, resilience, and resistance

Managers require quantitative yet tractable tools that can identify areas for restoration yielding effective benefits for targeted wildlife species and the ecosystems they inhabit. A spatially explicit conservation planning tool that guides effective sagebrush restoration for sage-grouse can be made more effective by integrating baseline maps describing existing (pre-restoration) habitat suitabili
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Western Ecological Research Center (WERC)

Geospatial data for object-based high-resolution classification of conifers within the geographic range of the Bi-State Distinct Population Segment of greater sage-grouse in California and Nevada

These products were developed to provide scientific and correspondingly spatially explicit information regarding the distribution and abundance of conifers (namely, singleleaf pinyon (Pinus monophylla), Utah juniper (Juniperus osteosperma), and western juniper (Juniperus occidentalis)) in Nevada and portions of northeastern California. Encroachment of these trees into sagebrush ecosystems of the G
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Ecosystems, Sage-grouse & Sagebrush Ecosystem, Western Ecological Research Center (WERC)

Summary Statistics Data for Greater Sage-Grouse (Centrocercus urophasianus) Nesting and Brood-Rearing Microhabitat in Nevada and California-Spatial Variation in Selection and Survival Patterns, 2009-16

This dataset provides summary statistics of multiple sage-grouse microhabitat characteristics of the Great Basin. These data support the following publication: Coates, P.S., Brussee, B.E., Ricca, M.A., Dudko, J.E., Prochazka, B.G., Espinosa, S.P., Casazza, M.L., and Delehanty, D.J., 2017, Greater sage-grouse (Centrocercus urophasianus) nesting and brood-rearing microhabitat in Nevada and Califo
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Western Ecological Research Center (WERC)

Spatially Explicit Modeling of Annual and Seasonal Habitat for Greater Sage-Grouse (Centrocercus urophasianus) in Nevada and Northeastern California - an Updated Decision-Support Tool for Management

Successful adaptive management hinges largely upon integrating new and improved sources of information as they become available. Updating management tools for greater sage-grouse ( Centrocercus urophasianus, hereafter referred to as sage-grouse) populations, which are indicators for the large-scale health of sagebrush ( Artemisia spp.) ecosystems in the Great Basin of North America, provide a time
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Western Ecological Research Center (WERC)

Integrating Spatially Explicit Indices of Abundance and Habitat Quality: An Applied Example for Greater Sage-grouse Management

This study provides timely and highly useful information about greater sage-grouse over a large area of the Great Basin. USGS researchers and their colleagues created a template for combining landscape-scale occurrence or abundance data with habitat selection data in order to identify areas most critical to sustaining populations of species of conservation concern. The template also identifies tho
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Western Ecological Research Center (WERC)
Filter Total Items: 165

Megafires and thick smoke portend big problems for migratory birds

In 2020, the fire season affecting the western United States reached unprecedented levels. The 116 fires active in September consumed nearly 20,822 km2 (https://inciweb.nwcg.gov/accessible-view/ Accessed 2020-09-29) with eighty percent of this footprint (16,567 km2) from 68 fires occurring within California, Oregon, and Washington. Although the 2020 fire season was the most extreme on record, it e
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Ecosystems, Western Ecological Research Center (WERC)

Migration stopover ecology of Cinnamon Teal in western North America

Identifying 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 spatiotemporal resolution GPS-GSM transmitters, we analyzed 61 fall migration tracks across western North America during our three
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Ecosystems, Western Ecological Research Center (WERC)

Wetland 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 Grizz
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Ecosystems, Western Ecological Research Center (WERC)

Informing wetland management with waterfowl movement and sanctuary use responses to human-induced disturbance

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 an
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Ecosystems, Western Ecological Research Center (WERC)

A tale of two valleys: Endangered species policy and the fate of the giant gartersnake

By the mid-20th Century, giant gartersnakes (Thamnophis gigas) had lost more than 90% of their Central Valley marsh habitat and were extirpated from more than two-thirds of their range. This massive habitat loss led to their inclusion in the inaugural list of rare species under the California Endangered Species Act (CESA). Listing under the CESA provided giant gartersnakes legal protection and mec
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Ecosystems, Western Ecological Research Center (WERC)

Changes in the abundance and distribution of waterfowl wintering in the Central Valley of California, 1973–2000

The Central Valley of California is one of the most important areas for wintering waterfowl in the world and the focus of extensive conservation efforts to mitigate for historical losses and counter continuing stressors to habitats. To guide conservation, we analyzed trends in the abundance and distribution (spatiotemporal abundance patterns) of waterfowl and their habitats in the Central Valley a
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Ecosystems, Western Ecological Research Center (WERC)

A customized framework for regional classification of conifers using automated feature extraction

Pinyon and juniper expansion into sagebrush ecosystems is one of the major challenges facing land managers in the Great Basin. Effective pinyon and juniper treatment requires maps that accurately and precisely depict tree location and degree of woodland development so managers can target restoration efforts for early stages of pinyon and juniper expansion. However, available remotely sensed layers
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Ecosystems, Western Ecological Research Center (WERC)

Nocturnal 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 recess
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Ecosystems, Western Ecological Research Center (WERC)

Interrupted 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 activit
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Ecosystems, Western Ecological Research Center (WERC)

Using high resolution satellite and telemetry data to track flooded habitats, their use by waterfowl, and evaluate effects of drought on waterfowl and shorebird bioenergetics in California

Wetland managers in the Central Valley of California, a dynamic hydrological landscape, require information regarding the amount and location of existing wetland habitat to make decisions on how to best use water resources to support multiple wildlife objectives, particularly during drought. Scientists from the U.S. Geological Survey Western Ecological Research Center (WERC), Point Blue Conservati
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Ecosystems, Western Ecological Research Center (WERC)

Seasonal impoundment alters patterns of tidal wetland plant diversity across spatial scales

Understanding patterns of biodiversity is a key goal of ecology and is especially pressing in the current human‐caused biodiversity crisis. In wetland ecosystems, human impacts are centered around hydrologic manipulation including the common practice of wetland diking and impoundment. Constraining how wetland management influences plant biodiversity patterns across spatial scales will provide info
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Ecosystems, Western Ecological Research Center (WERC)

Waterfowl use of wetland habitats informs wetland restoration designs for multi‐species benefits

Extensive global estuarine wetland losses have prompted intensive focus on restoration of these habitats. In California, substantial tracts of freshwater, brackish and tidal wetlands have been lost. Given the anthropogenic footprint of development and urbanization in this region, wetland restoration must rely on conversion of existing habitat types rather than adding new wetlands. These restoratio
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Ecosystems, Western Ecological Research Center (WERC)
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Research Spotlight: Dabbling Ducks Prefer Managed Wetlands and Pond-Like Features in Suisun Marsh

A recent study by USGS scientists found that dabbling ducks in Suisun Marsh, California, spend about 98% percent of their time in managed wetlands...

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Dabbling Duck Flight Speeds: High Tech Update For the 21st Century

In a recent study, U.S. Geological Survey biologists used technologically advanced GSM-GPS transmitters to calculate migratory and non-migratory...

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Research Spotlight: California Central Valley Ducks Move Shorter Distances and Use Smaller Areas Than Expected

In a new publication, U.S. Geological Survey biologists report the results of real-time tracking of three species of dabbling ducks in California’s...

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Secrets of Suisun Marsh's Birds of Prey

Did you know that the USGS is studying raptors in California? Biologists with the USGS Western Ecological Research Center are hard at work in the...

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Livestock grazing effects on sage-grouse: study identifies options to sustain ranching and help wildlife

Effects of livestock grazing on greater sage-grouse populations can be positive or negative depending on the amount of grazing and when grazing occurs...

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Cumulative Effects of Wildfire Adversely Affect Greater Sage-Grouse in the Great Basin

Slowing fire-related population declines in greater sage-grouse in the Great Basin over the next 30 years may depend on the intensity of fire...
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Science and Products