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Montana Field Guide

Montana Field Guides

Common Wood-Nymph - Cercyonis pegala

Global Rank: G5
State Rank: S5

Agency Status


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General Description
[From Ferris and Brown 1981, Shepard 1986, Glassberg 2001, Guppy and Shepard 2001, Pyle 2002] Forewing 2.4-3.5 cm. The largest of the wood nymphs. Two basic color forms, sexes differ somewhat; in our region, upper forewing chocolate brown with two large yellow-rimmed eyespots (smaller and blacker on males), the bottom eyespot as large or larger than the top one for both sexes, forewing postmedian band prominent and extending to top of top eyespot; ventrally, forewing with eyespots as above, but often with blue centers (especially on females), hindwing dark to pale brown with darker striations, the outer half a little lighter or same shade as inner (basal) half, with a submarginal row of 1-6 small eyespots (more on males than females).

One flight; mid-May to late September across range, peak in July and August (Scott 1986, Glasberg 2001, Pyle 2002).

Diagnostic Characteristics
Identified by the two prominent forewing eyespots rimmed with yellow, the second larger or at least as large as the eyespot closest to wing tip, the postmedian band of the forewing prominent and extending to the top of the eyespot nearest the wingtip.

Species Range
Montana Range

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Range Comments
From east-central British Columbia south to central California and east across Canada and the US south of the boreal forest to the Atlantic Coast; absent in the lowland southwest from southern California through the Texas Gulf Coast (Scott 1986, Glassberg 2001). State-wide in Montana (Kohler 1980, Stanford and Opler 1993). Up to 3200 m elevation in Colorado, and to 2130 m in Oregon and Washington, but most abundant at lower elevations (Ferris and Brown 1981, Pyle 2002, James and Nunnallee 2011). Common to abundant (Glassberg 2001).

Summary of Observations Submitted for Montana
Number of Observations: 55

(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)


Moist grasslands, dry gullies, old fields, irrigated pastures, open woodlands, montane meadows, roadsides, parks and lawns (Ferris and Brown 1981, Scott 1986, Pyle 2002). In Glacier National Park, reported in xeric montane meadows (Debinski 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:
    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 a variety of grasses and sedges, including Andropogon, Avena, Carex, Danthonia, Festuca, Poa, Stipa, and Tridens (Scott 1986, Guppy and Shepard 2001, James and Nunnallee 2011). Adults feed on flower nectar (including Apocynum, Asclepias, Aster, Carduus, Cirsium, Centaurea, Chrysothamnus, Clematis, Dipsacus, Echinacea, Erigeron, Erioganum, Gaillardia, Geranium, Liatris, Lobelia, Medicago, Mentha, Monarda, Nasturtium, Rhus, Rosa, Rudbeckia, Solidago, Symphoricarpos, Tamarix, and Verbena) as well as sap and dung (Scott 1986, 2014).

Reproductive Characteristics
Females lay 200-300 eggs singly and haphazardly on or near grasses, frequently without attachment to anything. Females may aestivate during the hottest months (late July to early August). Depending on temperature, eggs hatch in 9-10 days, unfed L1 larvae diapause, and overwinter at colder temperatures. Larval instars last 9, 9, 5, 9, and 10 days in L1-L5 instars, respectively; no nest is built. Pupation occurs on the host plant, the pupae suspended from a bent stem or blade. Adults emerge from pupae in 12-20 days (Scott 1986, Guppy and Shepard 2001, Pyle 2002, James and Nunnallee 2011). Males patrol throughout the day in grassy areas, often near trees, to seek females (Scott 1975b, 1986); males live for 3-4 weeks, females more than 8 weeks (James and Nunnallee 2011).

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Citation for data on this website:
Common Wood-Nymph — Cercyonis pegala.  Montana Field Guide.  .  Retrieved on , from