Mardon skipper potentially occurs in these Oregon counties: Jackson, Klamath (Map may reflect historical as well as recent sightings)
The Mardon skipper butterfly is a candidate species.
An annual review of the Mardon skipper was conducted in 2007.
Historical Status and
The historical range and abundance of Mardon skippers
is not precisely known because no studies were conducted prior
to 1980. Historically, Mardon skippers were collected from three
counties in Washington (Thurston, Klickitat, and Yakima); two
counties in Oregon - Klamath and Jackson; and Del Norte county
in California. The Mardon skipper is now known from 37 sites located
in four geographic areas: southern Puget Sound and the Mt. Adams
area in Washington; the Siskiyou Mountains in southern Oregon;
and Del Norte, California. All these sites are small; most supporting
less than 50 individuals. There are three sites in the Cascade
Mountains, located between Soda Mountain and Fish Lake. Mattoon
et al. (1998) recently proposed that these Oregon populations be
considered a separate subspecies, Polites mardon klamathensis.
Description and Life
The Mardon skipper is a small (20 to 24 millimeters; <1 inch), tawny-orange
butterfly with a stout, hairy body. The upper surface of both
wings is orange with broad dark borders. From below, the wings
are light tan-orange with a distinctive pattern of light yellow
to white rectangular spots. Males are smaller than females and
have a small, dark brown streak on the upper surface of the forewings.
Mardon skippers have a fast, skipping flight, bent antennae clubs,
and a characteristic basking posture in which the forewings are
held at a 45-degree angle and the hind wings are fully spread.
Mardon skippers complete one life cycle annually, and adults
(in southern Oregon) emerge in June and July for a month-long
flight period. After mating, females deposit their eggs into native
bunchgrass where they hatch after six to seven days. Larvae feed
on fescue grass (Festuca sp.) for about three months and pupae
hibernate through the winter.
The Mardon skipper is found on glacial outwash prairies in the
Puget Sound lowlands, where it occupies open grasslands with abundant
Idaho fescue interspersed with early blue violet. In the Mt. Adams
area, the Mardon skipper is found in openings, Ceanothus breaks,
meadows, and fescue grasslands within Ponderosa pine savanna/woodland,
at elevations ranging from 1,900 feet to 5,100 feet (Pyle 2002).
The southern Oregon populations occur in meadow habitats surrounded
by incense cedar (Calocedrus decurrens), white fir (Abies
concolor) Douglas-fir (Psuedotsuga menziesii), Oregon
grape (Mahonia spp.), bedstraw (Galium spp.), and
wild cherry clover (Trifolium sp.) (Matoon et al. 1998). The
population in Del Norte County California is located at the edge
of a fog break area with serpentine soil.
Mardon skipper larvae feed on Idaho fescue and red fescue (F.
rubra). The populations in Puget Sound use Idaho fescue, while
populations in the Mt. Adams area use Idaho fescue and red fescue
as well as another unidentified fescue species. Adults require
a variety of nectar source plants. The short, open stature of
native, fescue bunchgrass stands allows Mardon skippers to readily
access nectar and oviposition plants on Puget Sound prairies.
Adults prefer blue violet (Viola adunca) but will feed
from a variety of flowers, though they strongly avoid Scotch broom
(Cytisus scoparius). Nectaring has been observed on common
vetch (Vicia sativa), prairie lupine (Lupinus sp.),
Idaho blue-eyed-grass (Sisyrinchium Idahoense), penstemon
(Penstemon spp.), sego lily (Calochortus subalpinus),
and wallflower (Erysimum linifolium) (Pyle 2002). The Oregon
adults avidly visit clover (Matoon et al. 1998).
Reasons for Decline
The major factor affecting this species is the loss of a large
percentage of the original prairie grasslands upon which it depends.
These grassland and savanna landscapes are threatened today by
forest encroachment, native and non-native plant invasions, development,
recreational activities, grazing, agricultural practices, and
application of herbicides. In addition to loss of habitat, the
butterflies are threatened by insecticides, control practices
for invasive plants, military training, fire, and recreational
Mattoon, S.O., J.F. Emmel, and T.C. Emmel. 1998. The distribution
of Polites mardon (Lepidoptera: Hesperiidae) in North America,
and description of a new subspecies from southern Oregon. Pages
767-774 in T. C. Emmel, editor. Systematics of western North American
butterflies. Mariposa Press, Gainesville, Florida. 878pp.
Pyle, R.M. 2002. The Butterflies of Cascadia. Seattle Audubon
Society. Seattle, WA. 420 pp.