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Montana Field Guide

Montana Field Guides

Giant Sulphur - Colias gigantea

Potential Species of Concern
Native Species

Global Rank: G5
State Rank: S3

Agency Status

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General Description
Variously considered a subspecies of Colias scudderi and a full species (Klots 1940; Ferris and Brown 1981; Scott 1986; Ferris 1987; Guppy and Shepard 2001; Pyle 2002; Hammond and McCorkle 2008). The subspecies of C. gigantea considered most prevalent and widespread in Montana has recently been renamed from harroweri to kohleri, both still retained as subspecies of C. scudderi (Hammond and McCorkle 2008), with kohleri perhaps originating through hybridization between C. scudderi and C. occidentalis and converging in appearance to C. gigantea! Given the taxonomic uncertainty and instability, this account probably includes information pertaining to more than one species.

[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 2.4-2.8 cm. Medium sized. Wing fringes yellow tinged with pink in male, all-pink in female. Uppersurface of male yellow with narrow and complete black border, lower edge of forewing straight; females dimorphic, pale yellow form (often) and white form, both with black border often reduced or absent to apically pronounced in the forewing. In both sexes, undersurface of forewing lacking submarginal black spots or patches, hindwing undersurface with large pink-rimmed and elliptical cell spot (wider than high), often with small satellite spot above it.

One flight; late June to August (Scott 1986). Mainly July to mid-August (Glassberg 2001). Late July to August in the Rocky Mountain states (Ferris and Brown 1981; Ferris 1987), late June through July in British Columbia (Guppy and Shepard 2001).

Diagnostic Characteristics
Usually distinguished by a combination of the wing fringes yellow tinged with pink in male, all-pink in female, the uppersurface of male yellow with narrow and complete black borders; female in 2 forms, yellow or white, both may have black border reduced or lacking to apically pronounced in forewing; undersurface without submarginal black spots, hindwing with large pink-rimmed and elliptical cell spot (wider than high), often with small satellite spot above it.

Species Range
Montana Range Range Descriptions


Range Comments
Northern Alaska east to Northwest Territories and across boreal Canada to northern Manitoba and Ontario, south in the Rocky Mountains to British Columbia, Idaho, Montana, and northwestern Wyoming; isolated population in Cypress Hills of Alberta/Saskatchewan (Ferris 1987; Opler and Wright 1999; Glassberg 2001); 2012 m to 2743 m elevation in Wyoming (Klots 1940; Ferris 1987), about 1829 m elevation in Idaho and Alberta (Ferris 1987), near sea level in the Arctic (Oosting and Parshall 1978; Ferris 1987). In Montana, reported from at least 9 western counties east to Carbon County (Kohler 1980; Stanford and Opler 1993; FLMNH Lepidopterists' Society database), 1829 m to at least 3048 m elevation. Rare to uncommon (Glassberg 2001).


Montane willow bogs, open boggy meadows, riparian bogs, seepage areas in semi-open lodgepole pine forest, tundra and taiga bogs (Klots 1940; Oosting and Parshall 1978; Ferris and Brown 1981; Scott 1986, 1992; Ferris 1987; Opler and Wright 1999; Hamond and McCorkle 2008). In Montana, reported from subalpine meadows, on mountain slopes, along creeks, in hydric montane meadows, always in open dwarf-willow bogs (Hammond and McCorkle 2008; Debinski et al. 2013); in Greater Yellowstone Ecosystem reported from wet willow bogs (Debinski and Pritchard 2002).

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:
    1. 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);
    2. Evaluating structural characteristics and distribution of each ecological system relative to the species' range and habitat requirements;
    3. Examining the observation records for each species in the state-wide point observation database associated with each ecological system;
    4. 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: 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.

    Literature Cited
    • 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.

Food Habits
Limited information. Larval food plants include several species of dwarf Salix inhabiting bogs and wet meadows (Klots 1940; Ferris and Brown 1981; Scott 1986, 1992; Guppy and Shepard 2001; Hammond and McCorkle 2008). Adults feed on flower nectar but flower species often not identified (Ferris and Brown 1981); reported feeding at Pedicularis and Chrysanthemum near Churchill, Manitoba (Oosting and Parshall 1978).

Reproductive Characteristics
Limited information. Females lay egg singly on host plant leaves. Eggs hatch in about 10 days, larvae feed on host plant leaves, diapause (hibernate) as L3 instar, exit diapause, grow to L5 instar, pupate and eclose the following spring or early summer (Oosting and Parshall 1978; Scott 1979, 1986; Ferris 1987; Guppy and Shepard 2001; Hammond and McCorkle 2008). Males patrol throughout the day near shrub willows in search of females (Scott 1986).

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Citation for data on this website:
Giant Sulphur — Colias gigantea.  Montana Field Guide.  .  Retrieved on , from