Ring-billed Gull - Larus delawarensis
Medium-sized, white-headed gull. Males: 46 to 54 cm, 400 to 700 g; feMales: 43 to 50 cm, 300 to 600 g. Pattern of plumage similar to Common Gull but upper wings and mantle distinctly paler contrasting noticeably with the extensive black on upper and lower surfaces of 5th and 7th primaries (Ryder 1993).
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.
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)
In the Bozeman area, normal migration periods are April 2 to May 15 and August 25 to November 15, with peaks April 15 and Ocobert 1. Two adults banded at Freezeout Lake were later reported from Blackfoot, Idaho and Sonora, Mexico (Rothweiler 1960).
Spring and fall migration prefers fresh water (lakes, river marshes, reservoirs, irigation and agricultural areas). Occurs inland more often than other species of gulls - near landfill sites, golf courses, farm fields. Winter range mostly on or near coast. Common around docks, wharves, harbors; scarce in pelagic waters; inland on reservoirs, lakes, ponds and streams, landfill sites, and shopping malls in large metropolitan centers (Ryder 1993).
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
Human Land Use
Recently Disturbed or Modified
Wetland and Riparian Systems
- Occasionally Associated with these Ecological Systems
Shrubland, Steppe and Savanna Systems
Main foods include fish, insects, earthworms, rodents, and grain (Ryder 1993). At Freezeout Lake, stomach contents included insects, oligochaetes, crustaceans, birds and mammals, and plant material believed to be consumed incidentally to consuming animals (Rothweiler 1960).
At Freezeout Lake, there was little interaction with L. californicus in mixed colonies. Species foraged at different distances from the colony, and nesting habitat was segregated with respect to vegetation into monospecific groups.
At Freezeout Lake, first eggs were layed on May 1; by May 8 nests had 1 to 4 (mostly 3) eggs. Nests were constructed of dried bulrush; in many cases nests were less than 6 inches apart (Rothweiler 1960). Statewide, nesting begins in late April, with bandable young present in mid-June (Davis 1961).
- Literature Cited AboveLegend: View Online Publication
- Davis, C.V. 1961. A distributional study of the birds of Montana. Ph.D. dissertation. Oregon State University, Corvallis. 462 pp.
- Marks, J.S., P. Hendricks, and D. Casey. 2016. Birds of Montana. Arrington, VA. Buteo Books. 659 pages.
- Rothweiler, R. A. 1960. Food habits, movements, and nesting of gulls, Freezout Lake, Teton County, Montana. Montana Fish and Game Department, Helena. Paper Number 494. 26 pp.
- Ryder, J.P. 1993. Ring-billed Gull (Larus delawarensis). Species Account Number 033. 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
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- [WWPC] Washington Water Power Company. 1995. 1994 wildlife report Noxon Rapids and Cabinet Gorge Reservoirs. Washington Water Power Company. Spokane, WA.
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- Baird, P. 1976. Comparative ecology of California and ring-billed gulls (Larus californicus and L. delawarensis). Ph.D. Thesis, University of Montana, Missoula.
- Baird, P. A. 1976. Comparative ecology of California and Ring-billed gulls (Larus californicus and L. delawarensis). Ph.D. dissertation, University of Montana, Missoula.
- Cameron, E. S. 1907. The birds of Custer and Dawson counties, Montana. Auk 24(3): 241-270.
- Casey, D. 2005. Rocky Mountain Front avian inventory. Final report. Prepared for the U.S. Fish and Wildlife Service and The Nature Conservancy by the American Bird Conservancy, Kalispell, Montana.
- Confluence Consulting Inc. 2013. Montana Department of Transportation Wetland Mitigation Monitoring Reports (various sites). MDT Helena, MT.
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- Johnsgard, P.A. 1979. Birds of the Great Plains: breeding species and their distribution. University of Nebraska Press, Lincoln. 539 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.
- 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: Musgrave Lake, Zurich, Montana. Proj. No. 130091.019. May 2003. In 2002 Wetland Mitigation Monitoring Reports, Vol. II.
- Lenard, S. 2006. Birds of Blaine County, Riparian Point Count Surveys 2005. Report to the Bureau of LandManagement, Havre Field Station, Havre, Montana. Montana Natural Heritage Program, Helena, MT. 16pp.plus appendices.
- Lenard, S. and P. Hendricks. 2005. Birds of selected grassland and riparian plots along the Rocky Mountain Front. Montana Natural Heritage Program for US Fish and Wildlife Service and The Nature Conservancy. 17pp + maps.
- Lenard, S., Compiler. 2005. Surveys for Animal Species of Concern in Sage and Grassland Landscapes in Montana. An unpublished report to the Montana Department of Fish, Wildlife & Parks, State Wildlife Grants Program. Montana Natural Heritage Program, Helena, Montana. 63pp.
- 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.
- Matthews, W.L. 1980a. Wibaux-Beach comparison study: Sydney, Glendive and Plevna Study Areas. Bureau of Land Management, Miles City, MT. 50 p.
- Matthews, W.L. 1981. Broadus-Pumpkin Creek baseline inventory - wildlife. Bureau of Land Management, Miles City, MT. 83 p.
- Montana Bird Distribution Committee. 2012. P.D. Skaar's Montana bird distribution. 7th Edition. Montana Audubon, Helena, Montana. 208 pp. + foldout map.
- 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.
- Powder River Eagle Studies, Inc., Gillette, WY., 2002, Spring Creek Mine 2001 Wildlife Monitoring. March 2002
- Rothweiler, R.A. 1960. Food habits, movements and nesting of gulls on a waterfowl area, Freezeout Lake, Teton County, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 29 p.
- Rundquist, V.M. 1973. Avian ecology on stock ponds in two vegetational types in north-central Montana. Ph.D. Dissertation. Bozeman, MT: Montana State University. 112 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.
- 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.
- Stewart, R.E. 1975. Breeding birds of North Dakota. Tri-College Center for Environmental Studies, Fargo, North Dakota. 295 pp.
- Sullivan, Daniel, 1982, Bait stations as a means of rodenticide presentation to control Columbian ground squirrrels. Technical Rep. 82-3. Sept. 1982.
- Thunderbird Wildlife Consulting, Inc., Gillette, WY., 2003, Spring Creek Mine 2002 Wildlife Monitoring. March 2003.
- TRC Environmental Corporation. 2009. Results of the 2008 grassland bird displacement study at the Judith Gap wind energy project, Wheatland County, Montana. Judith Gap Energy LLC. Chicago, IL. 24 pp + appendices.
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- Van Horn, R.C. 1993. Ferruginous Hawk and Prairie Falcon reproductive and behavioral responses to human activity near the Kevin Rim, Montana. M.Sc. Thesis. Bozeman, Montana: Montana State University. 86 p.
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- Additional Sources of Information Related to "Birds"