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Montana Field Guides

Eyed Brown - Lethe eurydice
Other Names:  Satyrodes eurydice

Potential Species of Concern
Native Species

Global Rank: G5
State Rank: S2S3

Agency Status

External Links

General Description
[From Ferris and Brown 1981; Scott 1986; Glassberg 2001] Forewing 2.2-2.9 cm. Upper surface ground color a warm dark brown; under surface ground color paler with dark brown lines within and just outside the cells of both wings, postmedian line on hindwing zigzags, strong submarginal eyespots (4-5 on forewing, 6-7 on hindwing) individually surrounded by pale yellow rings, eyespots pupilled with white.

One flight; late June to July (Scott 1986; Glassberg 2001), adult emergence scattered from mid-June to late August (Ferris and Brown 1981).

Diagnostic Characteristics
Determined by underwing pattern and structure of eyespots combined with zigzag of hindwing postmedian line.

Species Range
Montana Range Range Descriptions


Range Comments
Northern half of the eastern US and adjacent southern Canada, from the Atlantic coast west to extreme northeastern Montana and south in the west to northeastern Colorado; also extending northwest into boreal regions of central Saskatchewan and northern Alberta (Scott 1986; Glassberg 2001). Considered a Pleistocene relic of a eastern deciduous forest extension into the Pine Ridge region of northwestern Nebraska (Johnson 1975). In Montana, reported from three extreme northeastern counties: Richland, Roosevelt, Sheridan (FLMNH Lepidopterists' Society database; MNHP), perhaps adjacent Daniels County (Standford and Opler 1993). Rare in the west (Glassberg 2001).

Observations in Montana Natural Heritage Program Database
Number of Observations: 2

(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 sedge marshes, wet meadows, wooded and open riparian areas including ditches, streams, and sloughs (Shapiro and Carde 1970; Ferris and Brown 1981; Scott 1986, 1992; Glassberg 2001). At least one Montana locality (Medicine Lake National Wildlife Refuge) is a prairie-pothole wetland complex.

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 sedges (Carex, Scirpus) and grasses (Agrostis, Dactylis, Poa)(Shapiro and Carde 1970; Ferris and Brown 1981; Scott 1986, 1992); grasses preferred over sedges in Colorado. Adults seldom visit flowers, but do feed on flower nectar of Asclepias, Cirsium, Nasturtium, and also sap, dung, and mud (Scott 1986, 2014).

Reproductive Characteristics
Females often lay eggs singly and haphazardly on many plants; in Colorado reported to lay an average of 2 eggs per host plant. Larvae feed on leaves, build no nests. L3 and L4 instars hibernate (Scott 1986). Males in search of females patrol just above the vegetation and perch throughout the day; adults spend 80% of their time resting, typically flying no more than 6 m before landing, although distances of 30 m reported (Scott 1992).

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Citation for data on this website:
Eyed Brown — Lethe eurydice.  Montana Field Guide.  .  Retrieved on , from