Conservationists from the Oregon Zoo and its partners released 483 Oregon silverspot butterfly larvae in the coast range last week, marking the final group of the season in efforts to save the federally threatened species.
Once found along the entire Pacific Northwest coast, the Oregon silverspot butterfly now survives in only a few isolated areas. The latest release aims to boost one of those, Saddle Mountain, where the species hadn’t been seen since 1972.
“These silverspot populations would probably be extinct if it weren’t for the recovery program,” said Kelly Gomez, who leads the zoo’s butterfly conservation work.
The zoo raises the butterflies from eggs laid by wild females collected each summer. After hatching, the caterpillars overwinter in safe conditions before being released in spring. This year, nearly 2,000 zoo-reared caterpillars have been returned to the wild.
Zoo officials say Saddle Mountain was chosen as a reintroduction site due to its abundance of early blue violets, the sole food source for the caterpillars. The flowers have disappeared from much of the silverspot’s historic range due to habitat loss and invasive species.
Since 2000, the Oregon Zoo has released more than 35,000 silverspot butterflies in partnership with the Oregon Parks and Recreation Department, U.S. Fish and Wildlife Service, and Woodland Park Zoo.
“If we continue this work, we can give them a fighting chance at survival,” Gomez said.
