Mardon Skippers

Mardon Skipper

The Mardon skipper is a small, tawny-orange butterfly currently found at only four small, geographically disjunct, areas in Washington, Oregon and California.

In Washington, 9 of 18 historic sites are known to be occupied by the Mardon skipper, including Conboy Lake NWR. Based on several years of repeated survey effort, it has been concluded that populations at five historic sites have been extirpated, four in south Puget Sound and one in the southern Cascades. The current status of four other sites is uncertain. Grasslands of the Puget prairies and Washington’s southern Cascades are believed to support just a few hundred individuals.

In the southern Cascades, the Mardon skipper is found in open, fescue grasslands within ponderosa pine savanna/woodland, at elevations ranging from 1,900' to 5,100'. South Cascade sites vary in size from small, 1/2-acre or less meadows to large grassland complexes, and site conditions range from dry, open ridgetops, to areas associated with wetlands or riparian habitats. A variety of nectar source plants are important to the butterfly; on Conby Lake the short, open stature of native, fescue bunchgrass stands allows Mardon skippers to access nectar and oviposition plants.

In the south Cascades, the Mardon skipper relies on grasslands. However, during the past 150 years, native grasslands have been developed, fragmented and degraded. More than 95% of the original prairie grasslands are gone from western Washington. One reason is likely due to fire suppression. Fire historically played an important role in maintaining grassland plant communities, and suppression has allowed woodlands to encroach. Mardon skippers were likely more widespread and abundant prior to large-scale loss of their open, fescue-dominated, grassland habitat.

The grassland and savanna landscapes upon which Mardon skippers depend are threatened today by forest encroachment, invasion by native and non-native plants, development, recreational activities, grazing, agricultural practices and application of herbicides. The butterflies themselves are threatened by insecticides, control practices for invasive plants, military training, fire and recreational activities. Of the population sites remaining, many are under assault from invasive non-native plants and have human uses which are incompatible with butterfly management. At none of the Mardon skipper sites does a mandate and dedicated funding occur for managing the site for Mardon skipper habitat. Due to the Mardon skipper’s small population size, limited distribution, isolation and the numerous factors threatening the species and its remaining habitat, the Washington Department of Fish and Wildlife believes the species is vulnerable to extirpation and as such has classified it as a state endangered species.