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Silverspot butterflies need your love

Posted by Barbara Segal, Intern, Communications

Photo by Mike Patterson
It takes a village to save a butterfly. Our zoo community’s mission includes saving wildlife near and far, and to save the Oregon silverspot butterfly we team up with many dedicated organizations of wildlife experts and activists. This beautiful and important pollinator once fluttered among flowers in Washington and across the west coast, but now is only found in isolated patches in Oregon and northern California. Threatened by habitat loss and invasive species, the silverspot butterfly needs our help. This means everyone from government agencies to you, our zoo community! Working together, we can bring this the silverspot butterfly back from the brink. 

The first leg of the relay began when the U.S. Department of the Interior declared the silverspot butterfly threatened in 1980. This put the wheels in motion for conservation efforts, and in 1982 the U.S. Fish and Wildlife Service created a recovery plan, which was updated in 2001. Careful planning is always needed for a species to successfully rebound. Choosing the right strategies in the right places with the right partners help make the most out of conservation efforts.

Photo by Michael Cash
Woodland Park Zoo joined the Oregon silverspot butterfly team in 1999. Along with the Oregon Zoo and Lewis and Clark College, we give silverspot butterfly caterpillars a safe head start in life. It starts by teams from our zoos and our friends at US Fish and Wildlife going out into the field in Oregon in the few places where silverspot butterflies still hang on. We go at summer’s end, just as the adult butterflies are nearing the end of their life cycle. US Fish and Wildlife deliver to each zoo a careful selection of females who are still able to lay eggs once more after reproducing in their natural habitat. In our purpose-built labs, we give them the chance to leave us their precious offspring. By taking care of them over winter and spring, we keep the caterpillars safe from predators and other natural hazards, increasing their chances when they are returned to the wild.

When the eggs hatch into tiny larvae, they take a long drink and then curl up for the winter in tiny “yurts” (corrugated cardboard) we provide for them. Then, to replicate the natural conditions of the colder months, we put them in a refrigerator. Don’t worry, it’s one we keep just for them! No chance of a staff member grabbing the wrong lunch. A recent generous donation of another used refrigerator will help support the program – thanks, local donors!

After their long winter’s nap, called diapause, the tiny caterpillars emerge, and boy are they hungry! Lucky for them, our zoo community is prepared. Our horticultural team grows western blue violets (Viola adunca) just for them. The little guys are picky eaters (maybe like some of your little guys out there!). The blue violet leaves are the only food that will satisfy these hungry hungry larvae. As they fill up over 6-8 weeks, they keep growing, shedding their exoskeletons in several stages called “instars.”

Then the next stage of the magic happens—the caterpillars turn into pupae. Check out this video of their transformation – you will never be the same again! With a hard, smooth shell, they are protected while they give themselves the ultimate makeover. While they are safe inside their chrysalis, we join with our team again to take them back to the Oregon coast. Back with the Oregon Zoo, and U.S. Fish and Wildlife, we place the pupae in their release enclosures that protect them from larger predators for just a little longer. When they emerge, off they go to find food, life, and love!

Photo by Michael Cash
In 2012, Woodland Park Zoo and the Oregon Zoo as partners won the American Conservation Award for our Silverspot Butterfly Recovery Program. The award really belongs to all of you – our zoo community! We could not do this amazing work without you. Why? Your zoo ticket and the King County Parks levy fund this program. Without your generous support, the Oregon silverspot butterfly would be gracing fewer northwestern skies.

Photo by Mike Patterson
Vote YES for Silverspot butterflies on August 6!

The King County Parks Levy is up for renewal on August 6, 2019. Vote yes for our parks to protect and preserve thousands of acres of forests and open space throughout the county. In addition King County Levy funding directly supports critical areas of Woodland Park Zoo operations and programming including our endangered Northwestern Pond Turtle Program and our Silverspot Butterfly Program. Learn more at

Yes on Proposition 1 on King County ballots is an investment in the future of our community. Adding thousands of acres of wilderness, habitat, and open space to the King County Parks system is one more step along the path to a sustainable future.