Western Bluebird - Sialia mexicana
Small thrush, 16.5 to 19 cm in length, 24 to 31 g mass. Plumage sexually dimorphic. Adult male has bright, deep, cobalt-blue head (including chin and throat) and upperparts (including wings and tail), with chestnut breast (chestnut coloration may be bisected, laterally, by blue), and frequently chestnut back patches. Remaining underparts grayish, becoming blue-gray on belly and undertail-coverts. Adult female considerably duller and not extensively bluish. Head and throat gray, back gray-brown, abdomen and undertail-coverts grayish, blue in wings and tail. Adult plumages are similar throughout the year (Guinan et al. 2000).
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.
PLACEHOLDER(field is currently blank)
Western Hemisphere Range
Observations in Montana Natural Heritage Program Database
Number of Observations:
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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)
Western Bluebirds can usually be found in open coniferous and deciduous woodlands, parklike forests, edge habitats, burned areas and where moderate amounts of logging have occurred, provided a sufficient number of larger trees and snags remain to provide nest sites and perches (Guinan et al. 2000).
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
Human Land Use
Recently Disturbed or Modified
Wetland and Riparian Systems
- Occasionally Associated with these Ecological Systems
Forest and Woodland Systems
Human Land Use
Insects during the warmer months, but forages primarily on berries and fruits through the winter. Wintering individuals are especially abundant in years and in areas when mistletoe and juniper berry crops are plentiful (Guinan et al. 2000).
Nests usually found in rotted or previously excavated cavities in trees and snags, or between trunk and bark. Eggs are subelliptical to short subelliptical. Pale blue in color, occasionally white, unmarked. Clutch size typically 5 eggs (range 2 to 6). Near Fortine, egg dates are from May 8 to June 26. The young leave the nest as early as June 9. The latest date for young in the nest is July 7.
- Literature Cited AboveLegend: View Online Publication
- Guinan, J. A., P. A. Gowaty, and E. K. Eltzroth. 2000. Western Bluebird (Sialia mexicana). In The birds of North America, No. 510 (A. Poole and F. Gill, Eds.). Academy of Natural Sciences of Philadelphia and American Ornithologists’ Union. [Revised online 18 November 2008]
- Marks, J.S., P. Hendricks, and D. Casey. 2016. Birds of Montana. Arrington, VA. Buteo Books. 659 pages.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- American Ornithologists’ Union [AOU]. 1998. Check-list of North American birds, 7th edition. American Ornithologists’ Union, Washington, D.C. 829 p.
- Bailey, A.M. and R.J. Niedrach. 1965. Birds of Colorado. Denver Museum of Natural History. 895 pp.
- Confluence Consulting Inc. 2011. Montana Department of Transportation Wetland Mitigation Monitoring Reports (various sites). MDT Helena, MT.
- Diem, K. L. and S. I. Zeveloff. 1980. Ponderosa pine bird communities. In: R. M. DeGraff and N. G. Tilghman, eds. Workshop Proceedings: Management of western forests and grasslands for nongame birds. USDA. Forest Service General Technical Report INT-86. p. 170-197.
- 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.
- Dobkin, D.S. 1994. Conservation and management of neotropical migrant landbirds in the Northern Rockies and Great Plains. Univ. Idaho Press, Moscow, Idaho. 220 pp.
- Econ, Inc. 1988. Wildlife monitoring report, 1987 field season, Big Sky Mine. March 1988. In Peabody Mining and Reclamation Plan Big Sky Mine Area B. Vol. 8, cont., Tab 10 - Wildlife Resources. Appendix 10-1, 1987 Annual Wildlife Report.
- 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.
- Farrand, J. 1983. Audubon Society Master Guide to Birding, No. 2 Gulls to Dippers. Alfred A. Knopf, Inc. New York. New York, pp 176-178.
- Flath, Dennis and David Dickson. 1994 Systematic wildlife observations on the Blackfoot-Clearwater Wildlife Management Area 1991-1993. Montana Department of Fish, Wildlife and Parks.
- Flath, Dennis L., 1982, Statewide small mammal distribution and habitat association. Mammalian Nongame Ecology Studies, NG-1.0, 1. Avian Nongame Ecology Studies, NG-2.0, 1,2,3,4. Statewide Wildlife Research. Nongame Wildlife Research & Inventory. W-120-R-13 (5853) IV.
- 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.
- Henderson, S. 1997. Effects of fire on avian distributions and patterns of abundance over two vegetation types in southwest Montana : implications for managing fire for biodiversity. M.Sc. Thesis. Bozeman, MT: Montana State University. 95 p.
- Hutto, Richard L. 1995. "Composition of Bird Communities Following Stand-Replacement Fires in Northern Rocky Mountain (U.S.A.) Conifer Forests". Conservation Biology. 9 (5): 1041-1058.
- 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.
- Land & Water Consulting, Inc., Missoula, MT., 2002, Montana Dept. of Transportation Wetland Mitigation Monitoring Report, Year 2001: Beaverhead Gateway, Dillon, Montana. Proj. No. 130091.011. July 2002. In 2001 Wetland Mitigation Monitoring Reports, Vol. I.
- 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.
- Martin, T.E. 1988. Habitat and area effects on forest bird assemblages: is nest predation an influence? Ecology 69(1):74-84.
- McWethy, D.B. 2007. Bird response to landscape and pattern disturbance across productivity gradients in forests of the Pacific Northwest. Ph.D. Dissertation. Bozeman, MT: Montana State University. 184 p.
- Montana Bird Distribution Committee. 2012. P.D. Skaar's Montana bird distribution. 7th Edition. Montana Audubon, Helena, Montana. 208 pp. + foldout map.
- MT Fish, Wildlife & Parks. No date. Blackfoot-Clearwater Wildlife Management Area checklist.
- 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.
- Scott, V.E. and J.L. Oldemeyer. 1983. Cavity-nesting bird requirements and responses to snag cutting in ponderosa pine. Pages 19-23 in J. W. Davis, G. A. Goodwin, and R. A. Ockenfels (tech. coords.). USDA For. Serv. Gen. Tech. Rep. RM-99.
- Scott, V.E., J.E. Whelan, and P.L. Svoboda. 1980. Cavity nesting birds and forest management. Pages 311-324 in Management of Western Forests and Grasslands for Nongame birds. U.S. For. Serv. Gen. Tech. Rep. INT-86.
- 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.
- 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.
- Thompson, Richard W., Western Resource Dev. Corp., Boulder, CO., 1996, Wildlife baseline report for the Montana [Montanore] Project, Lincoln and Sanders counties, Montana. In Application for a Hard Rock Operating Permit and Proposed Plan of Operation, Montanore Project, Lincoln and Sanders Counties, Montana. Vol. 5. Stroiazzo, John. Noranda Minerals Corp., Libby, MT. Revised September 1996.
- 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.
- Verner, J., and L.V. Ritter. 1985. A comparison of transects and point counts in oak-pine woodlands of California. The Condor 87:47-68.
- White, C.M., N.J. Van Lanen, D.C. Pavlacky Jr., J.A. Blakesley, R.A. Sparks, J.M.Stenger, J.A. Rehm-Lorber, M.F. McLaren, F. Cardone, J.J. Birek and D.J. Hanni. 2011. Integrated monitoring of bird conservation regions (IMBCR): 2010 Annual Report. Brighton, CO: Rocky Mountain Bird Observatory. 387 p.
- Additional Sources of Information Related to "Birds"