Gadwall - Anas strepera
FWP Conservation Tier
Species sexually dimorphic. Males in alternate plummage have gray brown body with a white abdomen and black rump. Black and chestnut portions of some inner median and lesser wing-coverts, slate gray bill, and yellow legs. Females overall brownish color with distinctive bill color (orange yellow with dark longitudinal midsection and gray black lateral spots), and presence of white speculum.
Summary of Observations Submitted for Montana
Number of Observations:
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Map Help and Descriptions
(direct evidence "B")
(indirect evidence "b")
No evidence of Breeding
(regular observations "W")
(at least one obs. "w")
(Records associated with a range of dates are excluded from time charts)
Normal migration periods in the Bozeman area are from March 20 to May 20 and from October 1 to November 10, with peak numbers reached on April 20 and October 15 (Skaar 1969).
At Bowdoin National Wildlife Refugem, Gadwall nest density was highest in saline lowlands, followed by dense nesting cover, panspots, and silty/ shallow clay. Nest success was highest in saline lowlands, then clay, panspots, silty sites and dense cover (Holm 1984).
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 (high, medium, or low) 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 2001, 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 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 associated as using 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 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.
High, medium, and low habitat quality was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species in the 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 assignments of habitat quality.
If you have any questions or comments on species associations with ecological systems, please contact Bryce Maxell at email@example.com
or (406) 444-3655.
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: http://mtnhp.org/requests/default.asp
) 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.
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- 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. 2001. The wild mammals of Montana. Special Publication No. 12. Lawrence, KS: The American Society of Mammalogists. 278 p.
- 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.
Diet consists mainly of submerged aquatic vegitation, seeds and aquatic invertebrates.
The primary cause of nest loss was depradation (67%) from (in order of importance): Striped Skunk, Red Fox, Coyote, Richardson's Ground Squirrel, Raccoon, avian, and American Mink. At Freezeout Lake, Striped Skunks were the major cause of unsuccessful nests.
The brood size was 6.2 in rest-rotation grazing pastures in north-central Montana. Nesting occurred from late May to the third week of August. At Freezeout Lake, island nesters were most successful (75%). The average of all types was 28%. The average clutch size was 11.9 and hatching dates were from May 21 to August 10.
- Additional ReferencesLegend: View WorldCat Record View Online Publication
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- American Ornithologists' Union. 1998. Check-list of North American birds. 7th edition. American Ornithologists' Union, Washington, D.C. 829 pp.
- Banks, R.C. and P.F. Springer. 1994. A century of population trends of waterfowl in western North America. Studies in Avian Biology, No. 15: 134-146.
- Belanger, L. 1988. Use of man-made ponds by dabbling duck broods. J. Wildl. Manage. 52(4): 718-723.
- Crabtree, R.L., L.S. Broome and M.L. Wolfe. 1989. Effects of habitat characteristics on Gadwall nest predation and nest site selection. J. Wildl. Manage. 53(1): 129-137.
- Decker Coal Company., 1979?, West Decker 5 Year Permit: Avian research and mitigation. In Decker Coal Company West Pit Permit. Vol. 3. 26.4.304(10-11), 305, 306, and 307. Updated Rules Rewrite, July 1, 1991.
- Duebbert, H.F., J.T. Lokemoen, and D.E. Sharp. 1983. Concentrated nesting of Mallards and Gadwalls on Miller Lake Island, North Dakota. J. Wildl. Manage. 47(5): 729-740.
- ECON, Inc. (Ecological Consulting Service), Helena, MT., 1975, Colstrip 10 x 20 Area wildlife and wildlife habitat annual monitoring report, 1975. Proj. 71-23-A. December 31, 1975.
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- ECON, Inc. (Ecological Consulting Service), Helena, MT., 1977, Colstrip 10 x 20 Area wildlife and wildlife habitat annual monitoring report, 1977. Proj. 164-85-A. December 31, 1977.
- ECON, Inc. (Ecological Consulting Service), Helena, MT., 1979, Annual wildllife report of the Colstrip Area for 1978. Proj. 195-85-A. April 6, 1979.
- ECON, Inc. (Ecological Consulting Service), Helena, MT., 1979, Annual wildllife report of the Colstrip Area for 1979, including a special raptor research study. Proj. 216-85-A. March 1, 1980.
- ECON, Inc. (Ecological Consulting Service), Helena, MT., 1979, Area B four-section wildlife report. August 3, 1979.
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- 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.
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- Lambing, John H., et al., 1994, Physical, chemical, and biological data for detailed study of the Sun River Irrigation Project, Freezout Lake Wildlife Management Area, and Benton Lake National Wildlife Refuge, west-central Montana, 1990-92, with selected data for 1987-89. May 1994. Open-file report 94-120.
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- Land & Water Consulting, Inc., Missoula, MT., 2002, Montana Dept. of Transportation Wetland Mitigation Monitoring Report, Year 2001: Johnson - Valier, Valier, Montana. Proj. No. 130091.018. July 2002. In 2001 Wetland Mitigation Monitoring Reports, Vol. I.
- Land & Water Consulting, Inc., Missoula, MT., 2002, Montana Dept. of Transportation Wetland Mitigation Monitoring Report, Year 2001: Musgrave Lake, Montana. Proj. No. 130091.019. July 2002. In 2001 Wetland Mitigation Monitoring Reports, Vol. II.
- Land & Water Consulting, Inc., Missoula, MT., 2002, Montana Dept. of Transportation Wetland Mitigation Monitoring Report, Year 2002: Fourchette Creek Reservoir Complex, Phillips County, Montana. Proj. No. 130091.023. February 2003. In 2002 Wetland Mitigation Monitoring Reports, Vol. I.
- Land & Water Consulting, Inc., Missoula, MT., 2002, Montana Dept. of Transportation Wetland Mitigation Monitoring Report, Year 2002: Musgrave Lake, Zurich, Montana. Proj. No. 130091.019. May 2003. In 2002 Wetland Mitigation Monitoring Reports, Vol. II.
- 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.
- Leschack, C. R., S. K. Mckinght, and G. R. Hepp. 1997. Gadwall (Anas strepera). Species Account Number 283. The Birds of North America Online (A. Poole, Ed.). Ithaca, NY: Cornell Laboratory of Ornithology; Retrieved 3/25/2008 from The Birds of North America Online database: http://bna.birds.cornell.edu/bna/
- Lokemoen, J.T., H.F. Duebbert, and D.E. Sharp. 1990. Homing and reproductive habits of Mallards, Gadwalls, and Blue-winged Teal. Wildl. Monogr. 106:1-28.
- Mack, G.D. and L.D. Flake. 1980. Habitat relationships of waterfowl broods on South Dakota stock ponds. J. Wildl. Manage. 44(3): 695-700.
- Palawski, D.U., et al., 1991, Contaminant biomonitoring at the Benton Lake National Wildlife Refuge in 1988.
- Palmer, R. S. 1962. Handbook of North American birds. Vol. 1. Loons through flamingos. Yale University Press, New Haven. 567 pp.
- Stewart, R.E. and H.A. Kantrud. 1973. Ecological distributions of breeding waterfowl populations in North Dakota. J. Wildl. Manage. 37(1): 39-50.
- Stewart, R.E. and H.A. Kantrud. 1974. Breeding waterfowl populations in the Prairie Pothole Region of North Dakota. Condor 76: 70-79.
- 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.
- Western Energy Co., Colstrip, MT. Unpub., 1983, Western Energy Company's Application for Amendment to Surface Mining Permit NO. 8003, Area B: sections 7, 8, 17,18 T1N R41E, sections 12, 13 T1N R40E, Mining Expansion. March 1983.
- Western Energy Co., Colstrip, MT., 1980, Western Energy Company Rosebud Mine, Colstrip, Montana: Annual Wildlife Report, 1980.
- Western Energy Co., Colstrip, MT., 1981, Western Energy Company Rosebud Mine, Colstrip, Montana: Annual Wildlife Report, 1981.
- Western Technology and Engineering, Inc. (WESTECH)., 2000, Wildlife Monitoring Absaloka Mine Area Annual Report, 1999. Montana SMP 85005. OSMP Montana 0007E. February 2000.
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