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Montana Field Guide

Montana Field Guides

Bronze Copper - Tharsalea hyllus

Native Species

Global Rank: G5
State Rank: S5

Agency Status


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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001] Forewing 1.6-2.1 cm. Uppersurface of male iridescent orangish-purple with broad orange marginal band on hindwing, female forewing yellow-orange with black spots, hindwing with a broad paler-orange marginal band. Undersurface of forewing for both sexes orange with black spots, hindwing undersurface gray-white with black spots and broad orange marginal band with small black spots at inner and outer margins.

Two flights in most of range, mid-June to mid July and mid-August to mid-September; one flight in north and at higher elevation in Colorado, mid-July to mid-August (Scott 1986). Mostly June to early July and August to early September, in Kansas and Nebraska mid-May to September, in Saskatchewan early July to early August (Glassberg 2001). In south-central Colorado, one flight in mountains late July to late August, two flights in plains early June to late July and mid-August to early October (Scott and Scott 1978).

Diagnostic Characteristics
Best determined by the forewing undersurface for both sexes orange with black spots, hindwing undersurface gray-white with black spots and broad orange marginal band with small black spots at inner and outer margins.

Species Range
Montana Range Range Descriptions


Range Comments
Southern Canada and the Great Lakes states south to Oklahoma, Arkansas, Mississippi, West Virginia, Maryland, and west across boreal Canada to extreme northeastern British Columbia, Alberta, Montana, extreme eastern Idaho, eastern Colorado, with an isolated population in Utah (Scott 1986; Opler and Wright 1999; Glasberg 2001; Guppy and Shepard 2001); 1310 m to 2438 m elevation in Colorado, but usually below 1800 m (Brown 1957; Scott and Scott 1978; Ferris and Brown 1981). Locally rare to locally uncommon in the west (Glassberg 2001). Spreading west of continental divide in agricultural areas and wetlands (Opler and Wright 1999).

Observations in Montana Natural Heritage Program Database
Number of Observations: 3

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)


Open areas with low vegetation in or near marshes, bogs, wet meadows, seeps, lake shores, river flood plains (Brown 1957; Scott 1986; Opler and Wright 1999; Glassberg 2001). In Glacier National Park, Montana, reported from xeric montane meadows (Debinski 1993), wet meadows in the Greater Yellowstone Ecosystem (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
Larval food plants include Polygonum coccineum and several species of Rumex (Ferris and Brown 1981; Scott 1986, 1992, 2006). Adults feed on flower nectar, including Apocynum, Asclepias, Bidens, Carduus, Cirsium, Helianthus, Heliopsis, Polygonum, Solidago, Symphyotrichum, and Verbena (Scott 2014).

Reproductive Characteristics
Females lay eggs singly on host plant leaves (dead leaves if host plant growing in water), petioles, seeds, and in litter at base of host plant; eggs overwinter (hibernate). Larvae eat host leaves, build no nest (Scott 1979, 1986, 1992). Males perch throughout the day low to the ground along streams and on prominent vegetation in or near meadows where larval host plant abundant while waiting for passing females (Scott 1975b, 1986).

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Citation for data on this website:
Bronze Copper — Tharsalea hyllus.  Montana Field Guide.  .  Retrieved on , from