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Fender's Blue Butterfly - Surrogate

Photo of a Fender's blue butterfly by the USFWS

Scientific Name: Icaricia icarioides fenderi
Status: Endangered
Eco-region: Willamette Valley
Strategy Habitat: Grasslands
Type of Surrogate: Umbrella Species
Biological Objective: Meet the down-listing goal of two permanently protected networks in each of the three recovery zones.

  • General Characteristics

    Fender’s blue butterfly (Icaricia icarioides fenderi) is endemic to the Willamette Valley in northwestern Oregon. The species was believed to be extinct from 1937 until it was rediscovered in 1989. The species was listed as endangered in 2000. Currently, they range from Eugene to southwest Portland.

    A relatively small butterfly, Fender’s blue butterflies have a wingspan of approximately 2.5 centimeters (1 inch). Brilliant blue upper wings with a blackish wing margin and white fringe scales characterize the males. The upper wings of the females are brown with white fringe scales. The undersides of the wings of both sexes are creamish-tan with black spots surrounded by a fine, white border or halo. 

    Fender’s blue butterflies can be found in upland prairie and oak savanna habitats. They require nectar plants as a food source and a larval host plant (lupine [Lupinus sp.]) for reproduction.  

    The life cycle of a Fender’s blue butterfly begins in late spring or early summer when an adult female deposits an egg on the underside of a Kincaid’s lupine (Lupinus sulphureus spp. kincaidii) leaflet. The egg soon hatches and the larva feeds on lupine leaflets. The larva may pass through one molt before dropping to the ground in mid-June or July where it goes into hibernation for the fall and winter. The following March or April, the larva begins to feed on fresh lupine leaflets again. After three to four additional molts, it transforms into a butterfly in May and begins the cycle again.

    Reasons for Decline

    Fender’s blue butterfly is endangered because native prairie habitat has been converted to agriculture, subjected to fire suppression, invaded by non-native plants, or otherwise developed. By nature, prairies are a transient community, requiring disturbance to prevent a transition to forest. With extensive changes in fire regimes, disturbances that maintained native prairies have been substantially altered, allowing tree and shrub species to invade and shade low-growing Kincaid’s lupine, the species upon which this butterfly depends. The elimination of native prairie habitat due to agriculture, urbanization, and development contributed to Kincaid’s lupine being listed as a threatened species in 2000.

    Loss of native prairie habitat has also resulted in the isolation of butterfly populations, which were once inter-connected. As the number of sites declines and the distance between them increases, opportunities for adult movement between populations are reduced. Populations isolated in this manner face a higher risk of extinction because they are more vulnerable to natural and human-made disturbances.

    Role as a Surrogate Species

    Fender’s blue butterfly is an umbrella surrogate for several upland prairie species including lupine (Lupine sp.), Willamette daisy (Erigeron decumbens var. decumbens), western meadowlarks (Sturnella neglecta), and golden paintbrush (Castilleja levisecta). As an umbrella surrogate species, conservation initiatives geared toward Fender’s blue butterfly could help conserve other species that also occur in prairie habitat.

    Conservation Measures

    Fender’s blue butterfly recovery requires high quality prairie habitat for all life stages. Therefore, many of the management actions aimed at maintaining and improving habitat will benefit a variety of other grassland and oak savanna species. Creating a functioning network of butterflies and ‘stepping stone’ habitats is of paramount importance for this species. 

    Biologists from federal and state agencies and private conservation organizations are engaged in active research, conservation, and monitoring programs to improve the status of the species. The priority conservation actions for Fender’s blue butterfly include:

    1. Develop a strategic habitat conservation approach in Lane County.

    2. Achieve Salmon-Safe+ certification for upland prairie with Fender’s blue butterfly Safe Harbor Agreements.

    3. Improve habitat quality at protected Fender’s blue butterfly locations; increase native plant diversity, especially nectar species.


     “Strategic conservation Management in Oregon’s Willamette Valley”

    Oregon Fish and Wildlife Office: Fenders blue butterfly fact sheet


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