Raptor Research

BBI is the preeminent firm in the western United States for studies of raptors with over 40 years experience.   



Description of Services

BBI has a long history working with the California Condor.   Recent projects include a fatal flaw analysis for AES Wind, a Condor conservation and management plan for Tejon Ranch Corporation, and consultation regarding the Condor for Yokohl Ranch. Other recent but completed work includes fatal flaw analyses for Padoma Wind in San Benito, Mendocino and Monterey counties, and consultation on the Condor for the Alta-Oak Creek Mojave wind project at the Tehachapi Wind Resource Area.                 

In addition to the Condor projects listed above, BBI is also called upon frequently to advise on the effects or potential effects of wind power on raptors and other birds. As such, BBI has provided consulting services for Altamont Pass as well as Homestead, Manzana and Pine Tree projects at the Tehachapi Wind Resource Area.

Dr. Bloom has been hired as an expert witness by the Center for Biological Diversity for the "Friends of Fawnskin" at Big Bear Lake, San Bernardino County, in an attempt to prevent development of a marina in shoreline Bald Eagle habitat.  During this work, BBI and associates prepare and/or contribute to Endangered Species Act (Federal and State) biological assessments, NEPA and CEQA environmental impact reports, and provide expert advice to corporations, non-profit conservation groups, and federal and local government(s) on local, federal and international (i.e. Red Book) threatened and endangered species, conservation biology, natural resources ecology and general biological surveys.

Dr. Bloom has worked on international avian and herpetological research projects in the western U.S., Alaska, Peru, Ecuador, and India.  During this work, he has coordinated and logged over 500 helicopter and fixed wing flight hours to conduct nest survey work and aerial radio tracking of eagles, California Condors, Red-shouldered Hawks (Buteo lineatus), Red-tailed Hawks (B. jamaicensis) and other species.

Recently, BBI has conducted Golden Eagle (Aquila chrysaetos) wintering and or nesting surveys for:

  • Palen Solar Electric Generating System (BrightSource Energy), Riverside County, California
  • Rice Solar Energy Project (CH2MHILL), Riverside County, California
  • Mesa Wind Project (Brookfield Development Partners), Riverside County, California
  • Tejon Ranch Inc.
  • Gas Company, Aliso Canyon

BBI has completed eagle nesting surveys only (without winter surveys) for:

  • San Joaquin Cross Valley Loop Project (Southern California Edison), Tulare County, California

BBI is also working with several prime contractors on the development of Eagle Conservation Plans for projects in a variety of areas.  Recent Swainsons hawk surveys include:

  • San Joaquin Cross Valley Loop Project (SWCA), Tulare County, California
  • Tehachapi Renewable Transmission Project (Southern California Edison and ICF International), Los Angeles and Kern Counties, California
  • Tejon Ranch Inc. 

In an effort to learn more about home range use, BBI has attached dozens of satellite and GSM transmitters for West Virginia University, US fish and Wildlife service, US Geological Survey, California Department of fish and wildlife, Bureau of Land management, University of Umea, Sweden.


Selected Publications

Bloom, P.H., J.W. Kidd, and S.E.Thomas, T. Hipkiss, B. Hornfeldt, M. Kuehn, (in press).  Trapping Success Using Carrion with Bow Nets to Capture Adult Golden Eagles in Sweden.  Journal of Raptor Research.

Bloom, P.H., M.D. McCrary, J.M. Scott, J.M. Papp, K.J. Sernka, S.E. Thomas, J.W. Kidd, E.H. Henckel, J.L. Henckel, and M.J. Gibson (in press).  Northward Summer Migration of Red-Tailed Hawks Fledged from Southern Latitudes.  Journal of Raptor Research. 

Thomsen, S.K., C.E. Kroeger, P.H. Bloom, and A.L. Harvey. (in press). Space Use and Home Range Size of Barn Owls on Santa Barbara Island. Monographs of the Western North American Naturalist 7:xx–xx.

Moss, E.H.R., T. Hipkiss, E. Frauke, H. Dettki, P. Sandstrom, P.H. Bloom, J.W. Kidd, S.E. Thomas, B. Hornfeldt.  2014.  Home-range Size and Examples of Post-nesting Movements for Adult Golden Eagles (Aquila chrysaetos) in Boreal, Sweden.  Journal of Raptor Research. 48 (2):93-105.

Doyle, J.M., T.E. Katzner, P.H. Bloom, Y. Ji, B.K. Wijayawardena, J.A. DeWoody.  2014.  The Genome Sequence of a Widespread Apex Predator, the Golden Eagle (Aquila chrysaetos).  Plos One. 9 (4):1-11.

Chiang, S.N., P.H. Bloom, A.M. Bartuszevige, and S.E. Thomas. 2012. Home Range and Habitat Use of Cooper's Hawks in Urban and Natural Areas. In C.A. Lepczyk and P.S. Warren (editors). Urban bird ecology 45: 1-16

Bloom, P.H., J.M. Scott, J.M. Papp, S.E. Thomas and J.W. Kidd. 2011. Vagrant Western Red-shouldered Hawks: Origins, Natal Dispersal Patterns, and Survival. The Condor 113: 538-546

Houston, C.S. and P.H. Bloom. 2005. Turkey Vulture Marking History: The Switch From Leg Bands to Patagial Tags. North American Bird Bander 30: 59-64

Clark, W.S. and P.H. Bloom. 2005. Basic II and Basic III Plumages of Rough-legged Hawks. Journal of Field Ornithology 76: 83-89

P.H. Bloom and W.S. Clark. 2001. Molt and Sequence of Plumages of Golden Eagles, and a Technique for In-Hand Ageing. North American Bird Bander 26: 97-116

Collins, C.T. and P.H. Bloom. 2000. The Status of Harlan's Hawk in Southern California. Western Birds 31: 200-202

Goldstein, M.I., P.H. Bloom, J.H. Sarasola, and T.E. Lacher. 1999. Post-migration Weight Gain of Swainson's Hawks in Argentina. Wilson Bulletin 111: 428-432

Tietje W.D., P.H. Bloom, and J.K. Vreeland. 1998. Characteristics of Red-tailed Hawk Nest Sites in Oak Woodlands of Central California. Proceedings of a Symposium on Oak Woodlands: Ecology, Management, and Urban Interface Issues 0: 365-372

Hall, L.S., M.S. Morrison, and P.H. Bloom. 1997. Population Status of the Endangered Hawaiian Hawk. Journal of Raptor Research 31: 11-15

Bloom, P.H. and M.D. McCrary. 1996. The Urban Buteo: Red-shouldered Hawks in Southern California. In: Raptors in Human Landscapes, Adaptations to Built and Cultivated Environments. D.M. Bird, D.E. Varland, and J.J. Negro, eds. Academic Press 0: 31-39

Woodbridge, B., K.K. Finley and P.H. Bloom. 1995. Reproductive Performance, Age Structure and Natal Dispersal of Swainson's Hawks in the Butte Valley, California. Journal of Raptor Research 29: 187-192

Bloom, P.H.. 1994. The Biology and Current Status of the Long-eared Owl in Coastal Southern California. Bulletin of the Southern California Academy of Sciences 93: 1-12

Garrison, B.A. and P.H. Bloom. 1993. Natal Origins and Winter Site Fidelity of Rough-legged Hawks Wintering in California. Journal of Raptor Research 27: 116-118

Bloom, P.H., M.D. McCrary, and M.J. Gibson. 1993. Red-shouldered Hawk Home Range and Habitat use in Southern California. Journal of Wildlife Management 57: 258-265


Selected Technical Reports

Bloom, P.H.  2005.  Raptor Status and Management Recommendations for the Santa Monica Mountains and Simi Hills, Los Angeles and Ventura Counties, California.  Santa Monica Mountains National Recreation Area.

Bloom, P.H.  2002.  Breeding Raptor and Loggerhead Shrike Status and Management Recommendations for Site 300, Lawrence Livermore Laboratory, Livermore, CA.

Morrison, M.L., L.S. Hall and P.H. Bloom.  1994.  Hawaiian Hawk (Buteo solitaries) Population Survey. Prepared for U.S. Fish and Wildlife Service.

Bloom, P.H.  1980.  The Status of Swainson's Hawk in California, 1979.  Federal Aid in Wildlife Restoration, Project W_54_R_12, Non-game Wildlife Investigations. Job Final Report 11_8.0. 42p.

Bloom, P.H.  1980.  The Raptorial Birds of Camp Pendleton Marine Corps Base, San Diego County, California. Prepared for Dept of Defense. 33p.