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For more information on species & ecosystem science:

Wildlife Science
360-902-2515
wildthing@dfw.wa.gov

Fish Science
360-902-2700
fishpgm@dfw.wa.gov

Habitat Science
360-902-2534
habitatprogram@dfw.wa.gov

 

Raptor Ecology

 
  Adult female golden eagle, Kittitas County.
   
 
  Male ferruginous hawk incubates eggs at a nest on a transmission tower in Benton County.
   
 
  Current distribution of nesting golden eagles (brown) and ferruginous hawks (blue) in Washington.
   

About 32 species of diurnal and nocturnal birds of prey are found in Washington, including the endangered Pacific spotted owl (Strix occidentalis) , state threatened ferruginous hawk (Buteo regalis), state sensitive bald eagle (Haliaeetus leucocephalus) and peregrine falcon (Falco peregrinus), and four identified as state candidates for listing including the golden eagle (Aquila chrysaetos), flammulated owl (Otus flammeolus), burrowing owl (Athene cunicularia), and northern goshawk (Accipiter gentilis). Between 1970 and 2000 most raptor research by the Washington Department of Fish and Wildlife involved spotted owls, bald eagles, and peregrine falcons. The latter two species were recently down-listed from listed status following increases in their populations. Since 2000, much of our research focus on raptors has shifted to eastside studies in shrub-steppe and prairie habitats. Raptors in the arid lands of eastern Washington have been less-studied than their west-side counterparts. Our interest in eastside raptors stems from the need to address management concerns related to the loss and degradation of their nesting and wintering habitats, including declines in prey, and potential impacts from environmental contaminants and windpower development.

The ferruginous hawk is the largest ("regalis" or regal) soaring hawk (Buteo) in North America where it nests in grassland, shrub-steppe, and prairie ecosystems. Identified by the sharply contrasting white and rust-colored plumage (ferruginous from "ferrous", containing iron) this species was historically known as the "squirrel hawk". Not surprisingly, they thrive locally near concentrations of ground squirrels and other Sciurids including prairie dogs, as well as rabbits (Leporids), and pocket gophers (Geomyids). They build large nests on low, natural features in the landscape like talus slopes, pinnacles, and juniper trees, but will nest on man-made structures like transmission towers and windmills. Washington is at the northwestern-most extent of the nesting range that lies within the Columbia Basin (map). Most remaining nests in Washington are on fringes of native habitat adjacent to agriculture. Ferruginous hawks migrate from Washington in the fall. WDFW began surveying the species in the early 1980s, and the species was listed as threatened in 1983. We initiated research on the ecology of ferruginous hawks in 1999.

Golden eagles are distributed worldwide and occupy a wider range of native habitats than ferruginous hawks, from alpine meadows to arid deserts. In North America there has been recent concern about the status of the species due to factors including large-scale changes in arid land environments, particularly in the grasslands and shrub-steppe habitats of the western United States. Washington supports nesting golden eagles east and west of the Cascade Mountains, as well as a winter migratory population from nesting populations in Canada and Alaska. The species has been identified as a state candidate for listing due to declines in the number of nesting pairs at historic nests. The focus of our research since 2004 has been to better understand the basic ecology of nesting golden eagles in Washington with a particular emphasis on movements, and the potential effects of lead contamination and prey populations on nest occupancy.

Projects

  • Golden eagle contaminants, residency, and range use
  • Raptors and wind power
  • Ferruginous hawk migration ecology
  • Range use of a shrub-steppe raptor guild before and after wind turbine construction
  • Wind turbine effects on adult ferruginous hawk ecology in the Columbia Basin
  • Determining ferruginous hawk food habits and nesting behavior by remote camera
  • Diet of nesting golden eagles in Washington

Publications

  • Efficacy of northern goshawk broadcast surveys in Washington state
  • Watson, J.W. 1990. Bald eagle dies from entanglement in fish net. Journal of Raptor Research 23:52-53.
  • Watson, J.W., R.G. Anthony, and M.G. Garrett. 1991. Time budgets and foraging ecology of bald eagles in the Columbia River estuary. Journal of Wildlife Management 55:492-499.
  • Watson, J.W. 1992. Status and distribution of bald eagles in Washington. Northwest Science 66:126.
  • Garrett, M.G., J.W. Watson, and R.G. Anthony. 1993. Bald eagle home range and habitat use in the Columbia River estuary. Journal of Wildlife Management 57:19-27.
  • Watson, J.W. 1993. Responses of nesting bald eagles to helicopter surveys. Wildlife Society Bulletin 21:171-178.
  • Watson, J.W., M. Davison, and L.L. Leschner. 1993. Bald eagles rear red-tailed hawks. Journal of Raptor Research 27:126-127.
  • Watson, J.W., and K.R. McAllister. 1993. Breeding distribution, population trends, and management of five diurnal raptor species in Washington state. Journal of Raptor Research 27:94.
  • Watson, J.W., and B.C. Cunningham. 1996. Another occurrence of bald eagles rearing a red-tailed hawk. Washington Birds 5:51-52.
  • Watson, J. W., D. J. Pierce, and B. C. Cunningham. 1999. An active bald eagle nest associated with unusually close human activity. Northwestern Naturalist 80:71-74.
  • Watson, J. W., D. W. Stinson, K. R. McAllister, and T. E. Owens. 2002. Population status of bald eagles in Washington at the end of the 20th century. Journal of Raptor Research. 36:161-169.
  • Watson, J. W. 2002. Comparative home range and food habits of bald eagles nesting in four aquatic habitats in western Washington. Northwestern Naturalist 83:101-108.
  • Watson, J.W. 2003. Bald eagle nesting chronology in western Washington. Washington Birds 9:8-11.
  • Watson, J. W. 2004. Responses of nesting bald eagles to experimental pedestrian activity. Journal of Raptor Research 38:295-304.
  • Watson, J.W., D.W. Hays, S.P. Finn, and P. Meehan-Martin. 1998. Prey of breeding northern goshawks in Washington. Journal of Raptor Research 32:297-305.
  • Base, D.L., S. Zender, and J.W. Watson. 2007. Golden eagles (Aquila chrysaetos) build new nest below cliff and provision fallen nestling. Journal of Raptor Research 41:76-77.

Reports

  • Washington state status report for the bald eagle
  • Migration and winter ranges of ferruginous hawks from Washington: 2000 Progress Report
  • Migration and winter ranges of ferruginous hawks from Washington: 2001 Progress Report
  • Migration and winter ranges of ferruginous hawks from Washington: Final Report
  • Range use and contaminants of golden eagles in Washington. Progress Report 3
  • Watson, J.W., D. Mundy, J.S. Begley, and D.J. Pierce. 1995. Responses of nesting bald eagles to the harvest of geoduck clams (Panopea abrupta). Final Report. Washington Department of Fish and Wildlife, Olympia. 23pp.
  • Watson, J.W., and D. J. Pierce. 1997. Movements and Ranges of nesting bald eagles at Naval Air Station Whidbey Island as determined by satellite telemetry. Final Report. Washington Department of Fish and Wildlife, Olympia. 15p.
  • Watson, J.W., and D. J. Pierce. 1998. Migration, diets, and home ranges of breeding bald eagles along Hood Canal and at Indian Island, Washington. Final Report. Washington Department of Fish and Wildlife, Olympia. 7p.
  • Watson, J.W., and D. J. Pierce. 1998. Bald eagle ecology in western Washington with an emphasis on the effects of human activity. Final Report. Washington Department of Fish and Wildlife, Olympia. 197p.
  • Watson, J.W., and D.J. Pierce. 2001. Skagit River bald eagles: movements, origins, and breeding population status. Final Report. Washington Department of Fish and Wildlife, Olympia. 79p.
  • Bald eagle (Haliaeetus leucocephalus). In E. M. Larsenand N. Nordstrom, editors. Management Recommendations for Washington's Priority Species, Volume IV: Birds
  • Watson, J.W. 2003. Scientists seek reasons for declining ferruginous hawk population. Washington Department of Fish and Wildlife. Online Science Magazine.
  • Watson, J.W., and U. Banasch. 2003. A Tri-National investigation of ferruginous hawk migration. Progress Report 1. Washington Department of Fish and Wildlife, Olympia, Washington, USA and Canadian Wildlife Service, Edmonton, Alberta , Canada.
  • Meyer, R.A., J.W. Watson, and A. Lafón Terrazas. 2003. Equipping wintering Ferruginous Hawks with satellite transmitters in Chihuhua, Mexico, January 2003. Report submitted to Migratory Bird Program/Prairie Wings, The Nature Conservancy. Contract no. MBP/PW-121002.
  • Meyer, R.A., J.W. Watson, and A. Lafón Terrazas. 2004. Equipping wintering Ferruginous Hawks with satellite transmitters in Chihuhua, Mexico, January 2004. Report submitted to Migratory Bird Program/Prairie Wings, The Nature Conservancy. Contract no. MBP/PW-121003.
  • Watson, J.W., and U. Banasch. 2004. A Tri-National investigation of ferruginous hawk migration. Progress Report 2. Washington Department of Fish and Wildlife, Olympia, Washington, USA and Canadian Wildlife Service, Edmonton, Alberta , Canada.
  • Watson, J.W., and U. Banasch. 2005. A Tri-National investigation of ferruginous hawk migration. Progress Report 3. Washington Department of Fish and Wildlife, Olympia, Washington, USA and Canadian Wildlife Service, Edmonton, Alberta , Canada.
  • Watson, J.W. 2006. A Tri-National investigation of ferruginous hawk migration. Progress Report 4. Washington Department of Fish and Wildlife, Olympia, Washington, USA and Canadian Wildlife Service, Edmonton, Alberta , Canada.
  • Watson, J.W. 2007. A Tri-National investigation of ferruginous hawk migration. Update. Washington Department of Fish and Wildlife, Olympia, Washington, USA and Canadian Wildlife Service, Edmonton, Alberta , Canada.
  • Watson, J.W. 2008. A Tri-National investigation of ferruginous hawk migration. Update. Washington Department of Fish and Wildlife, Olympia, Washington, USA and Canadian Wildlife Service, Edmonton, Alberta , Canada.
  • Watson, J.W., and R.W. Davies. 2005. Range use and contaminants of golden eagles in Washington. Progress Report 1. Washington Department of Fish and Wildlife, Olympia, Washington.
  • Watson, J.W., and R.W. Davies. 2006. Range use and contaminants of golden eagles in Washington. Progress Report 2. Washington Department of Fish and Wildlife, Olympia, Washington.