Puget blue (butterfly) (Plebejus icarioides blackmorei)

Close up of a Puget Blue butterfly open winged and on a lupine plant.
An adult Puget blue. (Rod Gilbert)
Close up of a Puget Blue butterfly close-winged and on a lupine plant.
An adult Puget blue. (Rod Gilbert)
Category: Butterflies and moths
Ecosystems: Westside prairie
State status: Candidate
If you see this species, please share your observation using the WDFW wildlife reporting tool or email us at  wildlife.data@dfw.wa.gov. Be sure to include a photo of the species for verification and location (latitude/longitude coordinates) of your observation. 

Climate vulnerability

Sensitivity to climate change

Sensitivity of this species is mainly driven by habitat. Populations associated with alpine meadows in the Olympic Mountains are likely very sensitive to climate-driven changes in habitat availability, as alpine habitats are projected to decline in extent due to warming temperatures, reduced snowpack, drought, and other drivers. Populations associated with lower elevation prairies are likely sensitive to fire. Lupine, the larval host plant of the Puget blue as well as an adult nectar source, appears to thrive post-fire, and fire also helps prevent prairie succession to forest or shrub habitats. However, fire can also lead to direct mortality of Puget blue adults and larvae, and/or facilitate the expansion of scotch broom and other invasive plants, which can displace lupine. In addition, it is unknown how shifting fire regimes (e.g., seasonality, intensity) will impact this species and its host plant.

Exposure to climate change

  • Increased temperatures
  • Reduced snowpack
  • Altered fire regimes


This species is identified as a Species of Greatest Conservation Need (SGCN) under the State Wildlife Action Plan (SWAP). SGCN-classified species include both those with and without legal protection status under the Federal or State Endangered Species programs, as well as game species with low populations. The WDFW SWAP is part of a nationwide effort by all 50 states and five U.S. territories to develop conservation action plans for fish, wildlife and their natural habitats—identifying opportunities for species' recovery before they are imperiled and more limited.
This species is identified as a Priority Species under WDFW's Priority Habitat and Species Program. Priority species require protective measures for their survival due to their population status, sensitivity to habitat alteration, and/or recreational, commercial, or tribal importance. The PHS program is the agency's main means of sharing fish and wildlife information with local governments, landowners, and others who use it to protect priority habitats for land use planning.