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Shannon M Skalos, PhD

Shannon Skalos is a Biologist with the North American Breeding Bird Survey (BBS) at the USGS Eastern Ecological Science Center. 

Shannon is a Biologist with the North American Breeding Bird Survey (BBS) at the USGS Eastern Ecological Science Center where she works collaboratively to implement and maintain the long-term, community-science based BBS. She is an ornithologist with expertise in avian ecology and applied conservation and management. Her research background focused on understanding migration, spatial ecology, habitat selection, reproduction, population ecology, and behavior to inform conservation and management of various listed and sensitive species including birds, mammals, reptiles, and amphibians. 

Professional Experience

  • Biologist, North American Breeding Bird Survey, U.S. Geological Survey, Eastern Ecological Science Center, Laurel, MD (2024–Present)

  • Senior Environmental Scientist, Statewide Avian Conservation Coordinator, California Department of Fish and Wildlife, Sacramento, CA (2022–2024)

  • Postdoctoral Researcher, U.S. Geological Survey, Western Ecological Research Center, Dixon, CA (2022)

  • Pathways Intern, U.S. Geological Survey, Western Ecological Research Center, Dixon, CA (2017–2021)

  • Graduate Student Researcher (Ph.D.), University of California, Davis (2015–2021)

  • Wildlife Biologist, U.S. Geological Survey, Western Ecological Research Center, Dixon, CA (2015–2017)

  • Biological Science Technician, U.S. Geological Survey, Western Ecological Research Center, Dixon, CA (2012–2015)

  • Wildlife Biologist, ICF International, Sacramento, CA (2011–2012)

  • Graduate Student Researcher (M.S.), University of California, Davis (2009–2011)

  • Field Research Assistant, Towson University, Big Horn, Wyoming (2008)

  • Undergraduate Student Researcher (B.S.), Towson University and Johns Hopkins University, Baltimore, MD (2007–2008)

Education and Certifications

  • Ph.D., Ecology, University of California, Davis, CA (2021)

  • M.S., Avian Sciences, University of California, Davis, CA (2011)

  • B.S., Biology, Towson University, MD (2008) 

Affiliations and Memberships*

  • American Ornithological Society

  • Association of Field Ornithologists

  • Raptor Research Foundation

  • The Wildlife Society

Honors and Awards

  • Early Career Professional Award, Women in Raptor Research, Raptor Research Foundation (2019)

  • STAR Award, U.S. Geological Survey, Western Ecological Research Center, Dixon, CA (2018)

  • Leadership Coin, U.S. Geological Survey, Western Ecological Research Center, Dixon, CA (2015) 

Science and Products

To catch a (marsh) predator: Modified trapping methods for breeding and wintering Northern Harriers (Circus hudsonius)

Although there are a variety of methods available for trapping raptors, some species, such as Northern Harriers (Circus hudsonius), are not easily captured with standard methods. We tested several existing trapping methods and modified two of them based on Northern Harrier ecology and behavior across seasons in a study population in California. No previously successful methods described...
Authors
Shannon Skalos, Michael L. Casazza, Matthew J. Falcon, William Thein, Joshua M. Hull
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

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...
Authors
Cory T. Overton, Austen Lorenz, Eric P. James, Ravan Ahmadov, John M. Eadie, Fiona McDuie, Mark J. Petrie, Chris A. Nicolai, Melanie L. Weaver, Daniel A. Skalos, Shannon Skalos, Andrea Lynn Mott, Desmond Alexander Mackell, Anna Kennedy, Elliott Matchett, Michael L. Casazza
By
Ecosystems Mission Area, 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...
Authors
Brian J. Halstead, Patricia Valcarcel, Richard Kim, Anna Jordan, Jonathan P. Rose, Shannon Skalos, Gabriel Reyes, Julia Ersan, Michael L. Casazza, Allison Essert, Alexandria M Fulton
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Ground-nesting great horned owl in Suisun Marsh, California

Great horned owls (Bubo virginianus) are widespread throughout North, Central, and parts of South America (Artuso et al. 2013). Across this range, great horned owls are generalists, occupying a diverse range of habitats including deciduous and coniferous forests, wetlands, and agricultural landscapes. Within these habitats, great horned owls are generally found near upland or short...
Authors
Shannon Skalos, Matthew J. Falcon, Olivia Wang, Andrea Lynn Mott, Melissa Hunt, Orlando Rocha, Josh T. Ackerman, Michael L. Casazza, Joshua M. Hull
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Actinemys marmorata (Western Pond Turtle): Suspected predation/scavenging

No abstract available.
Authors
Mickey Agha, Brian D. Todd, Shannon Skalos, Matthew J. Falcon, Michael L. Casazza, Olivia Wang
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Endangered species management and ecosystem restoration: Finding the common ground

Management actions to protect endangered species and conserve ecosystem function may not always be in precise alignment. Efforts to recover the California Ridgway’s Rail (Rallus obsoletus obsoletus; hereafter, California rail), a federally and state-listed species, and restoration of tidal marsh ecosystems in the San Francisco Bay estuary provide a prime example of habitat restoration...
Authors
Michael L. Casazza, Cory T. Overton, Thuy-Vy D. Bui, Joshua M. Hull, Joy D. Albertson, Valary K. Bloom, Steven Bobzien, Jennifer McBroom, Marilyn Latta, Peggy Olofson, Tobias M. Rohmer, Steven E. Schwarzbach, Donald R. Strong, Erik Grijalva, Julian K. Wood, Shannon Skalos, John Y. Takekawa
By
Ecosystems Mission Area, Western Ecological Research Center (WERC), San Francisco Bay and Sacramento-San Joaquin Delta Estuary

A preliminary investigation of the variables affecting the distribution of giant gartersnakes (Thamnophis gigas) in the Sacramento Valley, California

Giant gartersnakes (Thamnophis gigas) comprise a species of rare, semi-aquatic snake precinctive to the Central Valley of California. Because of the loss of more than 90% of their natural habitat, giant gartersnakes are listed as Threatened by the United States and California endangered species acts. Little is known, however, about the distribution of giant gartersnakes in the Sacramento...
Authors
Brian J. Halstead, Shannon M. Skalos, Michael L. Casazza, Glenn D. Wylie
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Terrestrial ecology of semi-aquatic giant gartersnakes (Thamnophis gigas)

Wetlands are a vital component of habitat for semiaquatic herpetofauna, but for most species adjacent terrestrial habitats are also essential. We examined the use of terrestrial environments by Giant Gartersnakes (Thamnophis gigas) to provide behavioral information relevant to conservation of this state and federally listed threatened species. We used radio telemetry data collected 1995...
Authors
Brian J. Halstead, Shannon M. Skalos, Glenn D. Wylie, Michael L. Casazza
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Non-USGS Publications**

Iverson A R, Schaefer J B, Skalos S M, and Hawkins C E. (2023). Global positioning system (GPS) and platform transmitter terminal (PTT) tags reveal fine-scale migratory movements of small birds: A review highlights further opportunities for hypothesis-driven research, Ornithological Applications, 125(3), duad014, https://doi.org/10.1093/ornithapp/duad014.
Murphy SM, Braun JV, Millam JR. (2011). Bathing behavior of captive Orange-winged Amazon parrots (Amazona amazonica). Applied Animal Behaviour Science 132: 200–210, https://doi.org/10.1016/j.applanim.2011.04.010
Johnson LS, Murphy SM, Parrish G. (2011). Determining the existence of predator scent detection in House Wrens, Troglodytes aedon. Journal of Field Ornithology 82(2): 150–157, https://www.jstor.org/stable/23011223
Airola DA, Jones J, Skalos S, Hunter C, Estep JA, Williams R, and Kaynor K. (2025). Bald eagle population increase, reproductive success, and nesting habitat in central interior California. California Fish and Wildlife Journal 111, e3, Bald eagle population increase, reproductive success, and nesting habitat in central interior California – California Fish and Wildlife Scientific Journal

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

Carolina Wrens and the Carters – A Brief History of the North American Breeding Bird Survey

Carolina Wrens and the Carters – A Brief History of the North American Breeding Bird Survey

Former President Jimmy Carter and First Lady Rosalynn were avid birders who assisted in the BBS, one of the nation’s most foundational sources for...

Read Article

Science and Products

To catch a (marsh) predator: Modified trapping methods for breeding and wintering Northern Harriers (Circus hudsonius)

Although there are a variety of methods available for trapping raptors, some species, such as Northern Harriers (Circus hudsonius), are not easily captured with standard methods. We tested several existing trapping methods and modified two of them based on Northern Harrier ecology and behavior across seasons in a study population in California. No previously successful methods described...
Authors
Shannon Skalos, Michael L. Casazza, Matthew J. Falcon, William Thein, Joshua M. Hull
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

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...
Authors
Cory T. Overton, Austen Lorenz, Eric P. James, Ravan Ahmadov, John M. Eadie, Fiona McDuie, Mark J. Petrie, Chris A. Nicolai, Melanie L. Weaver, Daniel A. Skalos, Shannon Skalos, Andrea Lynn Mott, Desmond Alexander Mackell, Anna Kennedy, Elliott Matchett, Michael L. Casazza
By
Ecosystems Mission Area, 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...
Authors
Brian J. Halstead, Patricia Valcarcel, Richard Kim, Anna Jordan, Jonathan P. Rose, Shannon Skalos, Gabriel Reyes, Julia Ersan, Michael L. Casazza, Allison Essert, Alexandria M Fulton
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Ground-nesting great horned owl in Suisun Marsh, California

Great horned owls (Bubo virginianus) are widespread throughout North, Central, and parts of South America (Artuso et al. 2013). Across this range, great horned owls are generalists, occupying a diverse range of habitats including deciduous and coniferous forests, wetlands, and agricultural landscapes. Within these habitats, great horned owls are generally found near upland or short...
Authors
Shannon Skalos, Matthew J. Falcon, Olivia Wang, Andrea Lynn Mott, Melissa Hunt, Orlando Rocha, Josh T. Ackerman, Michael L. Casazza, Joshua M. Hull
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Actinemys marmorata (Western Pond Turtle): Suspected predation/scavenging

No abstract available.
Authors
Mickey Agha, Brian D. Todd, Shannon Skalos, Matthew J. Falcon, Michael L. Casazza, Olivia Wang
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Endangered species management and ecosystem restoration: Finding the common ground

Management actions to protect endangered species and conserve ecosystem function may not always be in precise alignment. Efforts to recover the California Ridgway’s Rail (Rallus obsoletus obsoletus; hereafter, California rail), a federally and state-listed species, and restoration of tidal marsh ecosystems in the San Francisco Bay estuary provide a prime example of habitat restoration...
Authors
Michael L. Casazza, Cory T. Overton, Thuy-Vy D. Bui, Joshua M. Hull, Joy D. Albertson, Valary K. Bloom, Steven Bobzien, Jennifer McBroom, Marilyn Latta, Peggy Olofson, Tobias M. Rohmer, Steven E. Schwarzbach, Donald R. Strong, Erik Grijalva, Julian K. Wood, Shannon Skalos, John Y. Takekawa
By
Ecosystems Mission Area, Western Ecological Research Center (WERC), San Francisco Bay and Sacramento-San Joaquin Delta Estuary

A preliminary investigation of the variables affecting the distribution of giant gartersnakes (Thamnophis gigas) in the Sacramento Valley, California

Giant gartersnakes (Thamnophis gigas) comprise a species of rare, semi-aquatic snake precinctive to the Central Valley of California. Because of the loss of more than 90% of their natural habitat, giant gartersnakes are listed as Threatened by the United States and California endangered species acts. Little is known, however, about the distribution of giant gartersnakes in the Sacramento...
Authors
Brian J. Halstead, Shannon M. Skalos, Michael L. Casazza, Glenn D. Wylie
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Terrestrial ecology of semi-aquatic giant gartersnakes (Thamnophis gigas)

Wetlands are a vital component of habitat for semiaquatic herpetofauna, but for most species adjacent terrestrial habitats are also essential. We examined the use of terrestrial environments by Giant Gartersnakes (Thamnophis gigas) to provide behavioral information relevant to conservation of this state and federally listed threatened species. We used radio telemetry data collected 1995...
Authors
Brian J. Halstead, Shannon M. Skalos, Glenn D. Wylie, Michael L. Casazza
By
Ecosystems Mission Area, Western Ecological Research Center (WERC)

Non-USGS Publications**

Iverson A R, Schaefer J B, Skalos S M, and Hawkins C E. (2023). Global positioning system (GPS) and platform transmitter terminal (PTT) tags reveal fine-scale migratory movements of small birds: A review highlights further opportunities for hypothesis-driven research, Ornithological Applications, 125(3), duad014, https://doi.org/10.1093/ornithapp/duad014.
Murphy SM, Braun JV, Millam JR. (2011). Bathing behavior of captive Orange-winged Amazon parrots (Amazona amazonica). Applied Animal Behaviour Science 132: 200–210, https://doi.org/10.1016/j.applanim.2011.04.010
Johnson LS, Murphy SM, Parrish G. (2011). Determining the existence of predator scent detection in House Wrens, Troglodytes aedon. Journal of Field Ornithology 82(2): 150–157, https://www.jstor.org/stable/23011223
Airola DA, Jones J, Skalos S, Hunter C, Estep JA, Williams R, and Kaynor K. (2025). Bald eagle population increase, reproductive success, and nesting habitat in central interior California. California Fish and Wildlife Journal 111, e3, Bald eagle population increase, reproductive success, and nesting habitat in central interior California – California Fish and Wildlife Scientific Journal

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

Carolina Wrens and the Carters – A Brief History of the North American Breeding Bird Survey

Carolina Wrens and the Carters – A Brief History of the North American Breeding Bird Survey

Former President Jimmy Carter and First Lady Rosalynn were avid birders who assisted in the BBS, one of the nation’s most foundational sources for...

Read Article

*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government

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