The reappearance of the rare Island Marble butterfly (IMB) on San Juan Island after nearly 100 years continues to intrigue researchers and enthusiasts throughout the country.
The park, USFWS and the Washington Department of Fish and Wildlife continue to work with and assis private landowners outside the park with conservation strategies and habitat protection for the Island Marble butterfly.
Additionally, the park continues to investigate if the IMB can adapt to feeding and laying eggs on native rather than the nonnative mustards it is currently utilizing at American Camp. This will be critical in determining whether or not the park continues to incorporate native mustard plants into its ongoing prairie restoration plan.
The Island Marble is white and pale green with a mottled pattern of greenish-yellow under its hind wings. Look in the grassy prairie near wild mustard plants. Don’t confuse it with the more common Cabbage White, which is mostly white with a yellow underside and feeds on the same plants.
Protection status: Washington state Candidate (under review for listing as state Threatened or Endangered) species. The Federal government under the Endangered Species Act simply lists it as endangered. To read an article the National Park Service recently wrote about this journey, head here!
Last updated: August 26, 2020