Peregrine Falcon - Falco peregrinus
State Rank Reason (see State Rank above)
Impacts from the pesticide DDT in the mid 20th century caused catastrophic declines in abundance of this species across its range. A ban on this pesticide and subsequent conservation actions have recovered populations and resulted in delisting and removal of protections extended under the Endangered Species Act. In Montana the species had recolonized much of its historic range and continues to increase in abundance. This has resulted in its removal from the State species of Concern list in 2022.
- Details on Status Ranking and Review
Peregrine Falcon (Falco peregrinus) Conservation Status Review
Review Date = 12/22/2011
ScoreC - 250-1,000 individuals
CommentThe Montana Peregrine Institute documented 94 active Peregrine nest sites in 2011 which likely indicates a populaiton of between 250-1,000 individuals.
ScoreG - 200,000-2,500,000 km squared (about 80,000-1,000,000 square miles)
Comment380,531 square kilometers based on Natural Heritage Program range maps that appear on the Montana Field Guide
Area of Occupancy
ScoreU - Unknown
ScoreE - Relatively Stable (±25% change)
CommentAlthough species underwent drastic declines due to pesticides in the 1950s through 1970s, they have recovered to within +/- 25% of historic population sizes.
ScoreF - Increasing. Increase of >10% in population, range, area occupied, and/or number or condition of occurrences
CommentThe trend in Breeding Bird Survey (BBS) data is of very low credibility in Montana. Rangewide BBS shows a 64% increase per year. Raptor survey routes show 150% positive increase per year since 1976, but raptor survey route protocols may be inadiquate or marginal for detection of this species. Ralph Rogers report shows increasing trends with 14 active territories in 1994-1996 to 69 active territories between 2006-2008. In 2011, Jay Sumner from the Montana Peregrine Institute documented 94 active nesting sites.
ScoreF - Widespread, low-severity threat. Threat is of low severity but affects (or would affect) most or a significant portion of the population or area.
CommentNo major threat identified, but nest competition, falconry and nest disturbance may represent threats.
SeverityLow - Low but nontrivial reduction of species population or reversible degradation or reduction of habitat in area affected, with recovery expected in 10-50 years.
CommentSpecies has shown ability to recover relatively rapidly when pesticides were removed as a threat.
ScopeModerate - 20-60% of total population or area affected
CommentPotentially impact 20-60% of range/population.
ImmediacyLow - Threat is likely to be operational within 5-20 years.
CommentNo major operational threats identified
ScoreB - Moderately Vulnerable. Species exhibits moderate age of maturity, frequency of reproduction, and/or fecundity such that populations generally tend to recover from decreases in abundance over a period of several years (on the order of 5-20 years or 2-5 generations); or species has moderate dispersal capability such that extirpated populations generally become reestablished through natural recolonization (unaided by humans).
CommentModerately Vulnerable. Species exhibits moderate age of maturity, frequency of reproduction, and/or fecundity such that populations generally tend to recover from decreases in abundance within 5-20 years or 2-5 generations. Species has good dispersal capabilities such that extirpated populations generally become reestablished through natural recolonization.
ScoreB - Narrow. Specialist. Specific habitat(s) or other abiotic and/or biotic factors (see above) are used or required by the Element, but these key requirements are common and within the generalized range of the species within the area of interest.
CommentNarrow Specialist. Species is dependent on cliff habitat for nesting and these are relatively uncommon on the landscape. Other than that they are generalist forager for ducks, pigeons, and Galliformes.
Raw Conservation Status Score
3.5 – 0.5 (population size) + 0.0 (geographic distribution) + 0.25 (short-term trend) + 0.0 (threats)
The Peregrine Falcon has long pointed wings, a dark crown and nape, and a dark wedge extending below the eye. The forehead is pale in immature birds, which are mainly brownish above rather than black or gray as in adults. Arctic birds are relatively pale, and the Peregrine Falcons of the northwest coast of North America are very dark, compared to the intermediate coloration of the subspecies (anatum
) that once ranged across North America. They average 41 to 51 cm long and 91 to 112 cm in wingspan.
For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.
Smaller and less stocky in appearance than Gyrfalcons. Juvenile Peregrine Falcons are similar in size to Prairie Falcons, but are darker in color and have a heavy dark wedge on the side of the face.
Western Hemisphere Range
Observations in Montana Natural Heritage Program Database
Number of Observations:
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
SUMMER (Feb 16 - Dec 14)
Direct Evidence of Breeding
Indirect Evidence of Breeding
No Evidence of Breeding
WINTER (Dec 15 - Feb 15)
Not Regularly Observed
(Observations spanning multiple months or years are excluded from time charts)
Peregrine Falcons arrive in northern breeding areas late April to early May; departure begins late August-early September. In the Bozeman area, observations in the 1950's and 1960's suggested migration periods around May 5 and September 15 (Skaar 1969).
Nests typically are situated on ledges of vertical cliffs, often with a sheltering overhang. Ideal locations include undisturbed areas with a wide view, near water, and close to plentiful prey. Substitute man-made sites can include tall buildings, bridges, rock quarries, and raised platforms.
In fall in the Bozeman area, birds have been seen following flocks of shore birds at the lakes (Skaar 1969).
Ecological Systems Associated with this Species
- Details on Creation and Suggested Uses and Limitations
How Associations Were Made
We associated the use and habitat quality (common or occasional) of each of the 82 ecological systems mapped in Montana for
vertebrate animal species that regularly breed, overwinter, or migrate through the state by:
- Using personal observations and reviewing literature that summarize the breeding, overwintering, or migratory habitat requirements of each species (Dobkin 1992, Hart et al. 1998, Hutto and Young 1999, Maxell 2000, Foresman 2012, Adams 2003, and Werner et al. 2004);
- Evaluating structural characteristics and distribution of each ecological system relative to the species' range and habitat requirements;
- Examining the observation records for each species in the state-wide point observation database associated with each ecological system;
- Calculating the percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system to get a measure of "observations versus availability of habitat".
Species that breed in Montana were only evaluated for breeding habitat use, species that only overwinter in Montana were only evaluated for overwintering habitat use, and species that only migrate through Montana were only evaluated for migratory habitat use.
In general, species were listed as associated with an ecological system if structural characteristics of used habitat documented in the literature were present in the ecological system or large numbers of point observations were associated with the ecological system.
However, species were not listed as associated with an ecological system if there was no support in the literature for use of structural characteristics in an ecological system, even if
point observations were associated with that system.
Common versus occasional association with an ecological system was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species as represented in scientific literature.
The percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system was also used to guide assignment of common versus occasional association.
If you have any questions or comments on species associations with ecological systems, please contact the Montana Natural Heritage Program's Senior Zoologist.
Suggested Uses and Limitations
Species associations with ecological systems should be used to generate potential lists of species that may occupy broader landscapes for the purposes of landscape-level planning.
These potential lists of species should not be used in place of documented occurrences of species (this information can be requested at: mtnhp.org/requests
) or systematic surveys for species and evaluations of habitat at a local site level by trained biologists.
Users of this information should be aware that the land cover data used to generate species associations is based on imagery from the late 1990s and early 2000s and was only intended to be used at broader landscape scales.
Land cover mapping accuracy is particularly problematic when the systems occur as small patches or where the land cover types have been altered over the past decade.
Thus, particular caution should be used when using the associations in assessments of smaller areas (e.g., evaluations of public land survey sections).
Finally, although a species may be associated with a particular ecological system within its known geographic range, portions of that ecological system may occur outside of the species' known geographic range.
- Adams, R.A. 2003. Bats of the Rocky Mountain West; natural history, ecology, and conservation. Boulder, CO: University Press of Colorado. 289 p.
- Dobkin, D. S. 1992. Neotropical migrant land birds in the Northern Rockies and Great Plains. USDA Forest Service, Northern Region. Publication No. R1-93-34. Missoula, MT.
- Foresman, K.R. 2012. Mammals of Montana. Second edition. Mountain Press Publishing, Missoula, Montana. 429 pp.
- Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998. Montana atlas of terrestrial vertebrates. Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT. 1302 p.
- Hutto, R.L. and J.S. Young. 1999. Habitat relationships of landbirds in the Northern Region, USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-32. 72 p.
- Maxell, B.A. 2000. Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species. Report to U.S. Forest Service Region 1. Missoula, MT: Wildlife Biology Program, University of Montana. 161 p.
- Werner, J.K., B.A. Maxell, P. Hendricks, and D. Flath. 2004. Amphibians and reptiles of Montana. Missoula, MT: Mountain Press Publishing Company. 262 p.
- Commonly Associated with these Ecological Systems
Forest and Woodland Systems
Sparse and Barren Systems
Wetland and Riparian Systems
- Occasionally Associated with these Ecological Systems
Forest and Woodland Systems
Shrubland, Steppe and Savanna Systems
Peregrine Falcons feed primarily on birds (medium-size passerines up to small waterfowl). They have occasionally been reported to prey on small mammals (e.g., bats, lemmings), lizards, fishes, or insects (by young birds). Prey is pursued from a perch or while soaring. Peregrine Falcons may hunt up to several km from nest sites (Skaggs et al. 1988). In general, much hunting occurs in morning, and to lesser extent toward evening, but may hunt anytime during day. Excess prey is cached, especially during the breeding season.
Great Horned Owl may be a serious nest predator.
Nestlings have been reported in Montana from July 10 to 17 (Johnsgard 1986). The nesting period is estimated to be June and July (Davis 1961).
Clutch size averages 4 at mid-latitudes, and 3 in the far north. Incubation lasts 32 to 35 days, and is done mainly by female (the male brings food). Young birds fledge at 39 to 49 days, and gradually become independent. Brood losses are apparently caused mainly by bad weather, and lost clutches are usually replaced at alternate site.
Peregrine falcons first breed typically at 2 to 3 years of age, and occasionally as yearlings. They usually form a lifelong pair bond.
In some parts of Montana, Peregrine Falcons were considered fairly common in summer during the early 1900's (Skaar 1969). Post-war use of pesticides has been the main cause of the decline of these birds (Skaar personal communication).
- Literature Cited AboveLegend: View Online Publication
- Davis, C.V. 1961. A distributional study of the birds of Montana. Ph.D. Dissertation. Corvallis, OR: Oregon State University. 462 p.
- Johnsgard, P.A. 1986. Birds of the Rocky Mountains: with particular reference to national parks in the northern Rocky Mountain region. Colorado Associated University Press, Boulder, CO.
- Marks, J.S., P. Hendricks, and D. Casey. 2016. Birds of Montana. Arrington, VA. Buteo Books. 659 pages.
- Skaar, P.D. 1969. Birds of the Bozeman latilong: a compilation of data concerning the birds which occur between 45 and 46 N. latitude and 111 and 112 W. longitude, with current lists for Idaho, Montana, Wyoming, impinging Montana counties and Yellowstone National Park. Bozeman, MT. 132 p.
- Skaggs, R.W., D.H. Ellis, W.G. Hunt, and T.H. Johnson. 1988. Peregrine falcon. In: Glinski et al., eds. Proceedings of Southwest raptor management symposium and workshop. Natural Wildlife Federation Science and Technical Series Number 11. p. 127-136.
- Additional ReferencesLegend: View Online Publication
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- American Ornithologists’ Union [AOU]. 1998. Check-list of North American birds, 7th edition. American Ornithologists’ Union, Washington, D.C. 829 p.
- Becker, D.M. and Holt, D.W. 1982. A survey of raptor breeding activity and habitat utilization along the Missouri River in North Central Montana with special emphasis on Peregrine and Prairie Falcons.
- Becker, Dale M., 1980, A Survey of raptors on national forest land in Carter County, Montana. Final Progress Report: 1977-1979.
- Cade, T. J., et al. editors. 1988. Peregrine falcon populations: their management and recovery. The Peregrine Fund, Inc., Boise, Idaho. 949 pp.
- Cade, T.J. and R. Fyfe. 1970. The North American peregrine survey, 1970. The Canadian Field-Naturalist 84:231-245.
- Cameron, E. S. 1907. The birds of Custer and Dawson counties, Montana. Auk 24(3): 241-270.
- Casey, D. 2000. Partners in Flight Draft Bird Conservation Plan Montana. Version 1.0. 287 pp.
- Clark, T.W., H.A. Harvey, R.D. Dorn, D.L. Genter, and C. Groves (eds). 1989. Rare, sensitive, and threatened species of the greater Yellowstone ecosystem. Northern Rockies Conservation Cooperative, Montana Natural Heritage Program, The Nature Conservancy, and Mountain West Environmental Services. 153 p.
- Dobkin, D. S. 1992. Neotropical migrant landbirds in the Northern Rockies and Great Plains. U.S.D.A. For. Serv. N. Region Publ. R1-93-34. Missoula, Mont.
- Dood, A.R. 1980. Terry Badlands nongame survey and inventory final report. Montana Department of Fish, Wildlife, and Parks and Bureau of Land Management, Helena, MT. 70 pp.
- DuBois, K. and D. Becker. 1987. Identification of Montana's birds of prey. Montana Outdoors Nov/Dec. 20 p.
- Ehrlich, P., D. Dobkin, and D. Wheye. 1988. The birder’s handbook: a field guide to the natural history of North American birds. Simon and Schuster Inc. New York. 785 pp.
- Enderson, J.H. and J. Craig. 1974. Status of the peregrine falcon in the Rocky Mountains in 1973. The Auk 91(4):727-736.
- Evans, D. L. 1982. Status reports on twelve raptors. U.S. Department of the Interior, Fish and Wildlife Service, Special Scientific Report No. 238. 68 pp.
- Feigley, H. P. 1997. Colonial nesting bird survey on the Bureau of Land Management Lewistown District: 1996. Unpublished report, U.S. Bureau of Land Management, Lewistown, Montana.
- Flath, D. L. 1976. The peregrine falcon. Montana Outdoors 7(2):31-33.
- Flath, D. L. 1981. Evaluation of techniques for recovery of peregrine falcons in Montana. Job Prog. Rep., Endangered Species Project SE-l, Job 2. Mont. Dept. Fish, Wildt. and Parks. 3 pp.
- Flath, D. L. 1982. Evaluation of techniques for recovery of peregrine falcons in Montana. Job Prog. Rep., Endangered Species Project SE-l, Job 2. Mont. Dept. Fish, Wildlife, and Parks. 6 pp.
- Flath, D. L. 1983. Evaluation of techniques for recovery of peregrine falcons in Montana. Job Prog. Rep., Endangered Species Project SE-1, Job 2. Mont. Dept. Fish, Wildt. and Parks. 5 pp.
- Follman, B. and W. Murphy. 1988. Peregrine Falcon nesting habitat inventory and survey report. Deerlodge National Forest. 47 p.
- Gniadek, S. 1983. Southwest Glendive Wildlife Baseline Inventory. Miles City, Mont: Bureau of Land Management, Miles City District Office. 56 pp with appendices.
- Grebence, B. L. and C. M. White. 1989. Physiographic characteristics of peregrine falcon nesting habitat along the Colorado River system in Utah. Great Basin Nat. 49:408-418.
- Hall, S.P. and H.E. Legrand, Jr. 1989. Element stewardship abstract for Falco peregrinus, peregrine falcon. Arlington, VA: The Nature Conservancy. 9 p.
- Hayman, K.C. and Sumner, J. 1977. Peregrine and prairie falcon nesting survey and habitat analysis - Lolo National Forest. 16 p.
- Hays, R., R.L. Eng, and C.V. Davis (preparers). 1984. A list of Montana birds. Helena, MT: MT Dept. of Fish, Wildlife & Parks.
- Hejl, S.J., R.L. Hutto, C.R. Preston, and D.M. Finch. 1995. The effects of silvicultural treatments on forest birds in the Rocky Mountains. pp. 220-244 In: T.E. Martin and D.M. Finch (eds). Ecology and Management of Neotropical Migratory Birds. New York, NY: Oxford Univ. Press. 489 p.
- Hendricks, P., and K.H. Dueholm. 1995. Cliff-nesting raptor survey of the Sioux District, Custer National Forest: 1994. Unpubl. report to U.S.D.A. For. Serv., Custer N.F., Billings. 20 pp.
- Herman, M., and E. E. Willard. 1978. Peregrine falcon and its habitat. U.S.D.A. Forest Service Northern Region. 11 pp.
- Hinckley, D., ed. Montana peregrine management book. USDI Bureau of Land Management, Billings.
- Hinckley, Dan. 1985. Blackbook of Montana Peregrine Falcon Eyries. BLM Spec. Rep. 57 p.
- Johnsgard, P.A. 1990. Hawks, eagles, and falcons of North America. Smithsonian Institution Press, Washington, D.C. 403 pp.
- Johnsgard, P.A. 1992. Birds of the Rocky Mountains with particular reference to national parks in the northern Rocky Mountain region. Lincoln: University of Nebraska Press. xi + 504 pp.
- Joslin, Gayle, and Heidi B. Youmans. 1999. Effects of recreation on Rocky Mountain wildlife: a review for Montana. [Montana]: Montana Chapter of the Wildlife Society.
- Lenard, S. 1996. Peregrine falcon - Falco peregrinus, status: endangered. Montana Audubon Council fact sheet. 2 p.
- Lenard, S., J. Carlson, J. Ellis, C. Jones, and C. Tilly. 2003. P. D. Skaar's Montana bird distribution, 6th edition. Montana Audubon, Helena, MT. 144 pp.
- Lindler, B. Holter peregrines now on their own. Great Falls, MT: Great Falls Tribune. 28 July 1988. p. 3C.
- Lockhart, J. Michael, 1976, Effects of coal extraction and related development on wildlife populations. Annual progress report; Calendar year 1976. In Decker Coal Company West Pit Permit. Vol. 3. 26.4.304(10-11), 305, 306, and 307. Updated Rules Rewrite, July 1, 1991. Appendix F.
- Maxell, B.A. 2016. Northern Goshawk surveys on the Beartooth, Ashland, and Sioux Districts of the Custer-Gallatin National Forest: 2012-2014. Montana Natural Heritage Program. Helena, MT. 114pp.
- Maxim Technologies, Inc. 2003. Raptor Inventory Blackleaf Study Area. Draft Technical Report prepared for U.S. Department of the Interior, Bureau of Land Management, Lewistown Field Office. 16 p.
- Montana Bird Distribution Committee. 2012. P.D. Skaar's Montana bird distribution. 7th Edition. Montana Audubon, Helena, Montana. 208 pp. + foldout map.
- Mora, M. A. 1995. Residues and trends of organochloride pesticide and polychlorinated biphenyls in birds from Texas, 1965-88. Technical Report 14. Washington, D.C.: U.S.D.I. National Biological Service. 26 p.
- Oechsli, L.M. 2000. Ex-urban development in the Rocky Mountain West: consequences for native vegetation, wildlife diversity, and land-use planning in Big Sky, Montana. M.Sc. Thesis. Montana State University, Bozeman. 73 p.
- Olendorff, Richard R., and Robert N. Lehman, USDI Bureau of Land Management., 1986, Raptor collisions with utility lines: An Analysis using subjective field observations. Final Report. February 1986.
- Omland, K.S. and E.G. Meyer. 1992. Fall 1991 raptor migration study in the Bozeman, Montana vicinity. Prepared for the Gallatin National Forest, by HawkWatch International, Inc. 31 p.
- Porter, R.D., M.A. Jenkins, and A. L. Gaski. 1987. Working bibliography of the peregrine falcon. Natl. Wildl. Fed., Sci. and Tech. Ser. No. 9. 185 pp.
- Restani, M. and A.R. Harmata. 1992. Survey of raptors along the upper Missouri River, Montana. Montana State University. Bozeman, MT. 53 pp plus appendix.
- Rogers, R., et al. 1994. A survey for: peregrine falcons and other raptors nesting along the Upper Missouri River: Ft. Benton, MT to James Kipp State Park. Prepared for the Bureau of Land Management, Lewistown District Office, Contract # 1422E950P40197. 22 p.
- Rogers, Ralph and Jay Sumner. 2004. Montana Peregrine Falcon Survey. Centmont Bioconsultants. Winifred, Montana. 32 pp plus appendix.
- Saab, V. and C. Groves. 1992. Idaho's migratory landbirds, description, habitats & conservation. Nongame Wildlife Leaflet #10. Idaho Department of Fish and Game, UBLM, USFS, USFWS, National Fish and Wildlife Foundation. 16 p.
- Sater, S. 2022. The insects of Sevenmile Creek, a pictorial guide to their diversity and ecology. Undergraduate Thesis. Helena, MT: Carroll College. 242 p.
- Saunders, A. A. 1912. A horseback trip across Montana. Condor 14(6):215-220.
- Saunders, A.A. 1914. The birds of Teton and northern Lewis & Clark counties, Montana. Condor 16:124-144.
- Sibley, D. 2014. The Sibley guide to birds. Alfred A. Knopf, New York, NY. 598 pp.
- Skaar, P. D., D. L. Flath, and L. S. Thompson. 1985. Montana bird distribution. Montana Academy of Sciences Monograph 3(44): ii-69.
- Smith, J. 2000. Recap of the fall 2000 migration season, Bridger Mountains. Raptor Watch 15(1):6-10.
- Snow, C. 1972. Habitat management series for endangered species, Report No. 1: American Peregrine Falcon and Arctic Peregrine Falcon. Bureau of Land Management and the U.S. Dept. of the Interior, Tech. Note: T-N-167. 35 p.
- Sumner, J. and R. Rogers. 1999. Montana Peregrine Falcon Survey. Prepared for Montana Fish, Wildlife & Parks. 27 p. (plus maps and photos).
- Sumner, J. and R. Rogers. 2001. Montana Peregrine Falcon Survey. prepared for Montana Fish, Wildlife & Parks. 22 pp.
- Sumner, J. and R. Rogers. 2002. Montana Peregrine Falcon Survey. Prepared for Montana Fish, Wildlife & Parks. 29 p. plus appendix.
- Sumner, Jay and Ralph Rogers. 2006. Montana Peregrine Falcon Survey. Montana Peregrine Institute. Arlee, Montana. 36 pp plus appendix.
- Taylor, D.M. and C.H. Trost. 1987. The status of historically rare of unrecorded birds in Idaho. Unpublished manuscript. 68 p.
- Thompson, L.S. 1981. Circle West wildlife monitoring study: Third annual report. Technical report No. 8. Montana Department of Natural Resources and Conservation. Helena, Montana.
- U.S. Fish & Wildlife Service., 1984, Charles M. Russell National Wildlife Refuge, Montana: Draft Environmental Impact Statement.
- U.S. Fish & Wildlife Service., 1985, Charles M. Russell National Wildlife Refuge, Montana: Final Environmental Impact Statement.
- U.S. Fish and Wildlife Service. 1980. Management of Charles M. Russell National Wildlife Refuge. Draft. Reprint
- U.S. Fish and Wildlife Service. 1984. American peregrine falcon recovery plan (Rocky Mtn./southwest population). Prepared in cooperation with American peregrine falcon recovery team. Denver, CO: USFWS. 105 p.
- U.S. Fish and Wildlife Service. 1984. American Peregrine Falcon Rocky Mountains/southwest population recovery plan. Prepared in cooperation with the American Peregrine falcon recovery team. U.S. Fish Wildl. Serv., Denver. 105 pp.
- U.S. Forest Service, Kootenai National Forest. Montana Dept. of State Lands., 1978?, Final Environmental Impact Statement. Proposed Plan of Mining and Reclamation. Troy Project, Asarco, Inc., Lincoln County, Montana. Vol. III.
- U.S. Forest Service. 1991. Forest and rangeland birds of the United States: Natural history and habitat use. U.S. Department of Agriculture, Forest Service Agricultural Handbook 688. 625 pages.
- USDI National Park Service., 2000, Bison Management for the State of Montana and Yellowstone National Park. Final Environmental Impact Statement for the Interagency Bison Management Plan for the State of Montana and Yellowstone National Park. Vol. I. August 2000.
- Waage, B.C. 1986. Western Energy Company Rosebud Mine, Rosebud County, Montana: Annual Wildlife Monitoring Report, 1985 Field Season. December 1985.
- Waldt, R. 1995. The Pine Butte Swamp Preserve bird list. Choteau, MT: The Nature Conservancy. Updated August 1995.
- Watts, C.R. and L.C. Eichhorn. 1981. Changes in the birds of central Montana. Proceedings of the Montana Academy of Sciences 40:31-40.
- Wenzel, T. 1984. Identification of peregrine falcon nesting habitat. P. 71 .ill A. Dood, comp., Agriculture and Wildlife. Proc. Mont. Chapt., The Wildt. Soc., Butte. 85 pp.
- Western Technology and Engineering, Inc. (WESTECH)., 1993, Wildlife Monitoring Asaloka Mine Area Annual Report, 1992. Montana SMP 85005 R1. OSMP Montana 00078. 1993.
- White, C. M., N. J. Clum, T. J. Cade, and W. G. Hunt. 2002. Peregrine Falcon (Falco peregrinus). In The birds of North America, No. 660 (A. Poole and F. Gill, Eds.). Academy of Natural Sciences of Philadelphia and American Ornithologists’ Union.
- Wright, M. 1985. Prairie falcon and peregrine falcon survey on the Flathead Indian Reservation. University of Montana, Missoula. 81 pp.
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