For hundreds of endangered butterflies raised at the Oregon Zoo during the past year, naptime is over.
In February, zoo conservationists roused more than 500 Taylor’s checkerspot larvae from their winter dormancy, transferring these very hungry caterpillars into rearing cups at the zoo’s Imperiled Butterfly Conservation Lab, where they munched on narrowleaf plantain following a 7-month snooze.
Last week, zoo staffers joined biologists from the Washington Department of Fish and Wildlife to release the growing caterpillars on prairies in central Washington, where some of the region’s best checkerspot habitat remains.
"Releasing caterpillars reared at the zoo is part of our ongoing effort to reestablish this imperiled species at sites where it was once abundant," explained Mary Linders, a species recovery biologist with the Washington wildlife department. "Without large, connected populations, the butterflies struggle to survive."
The zoo-reared caterpillars will complete their development in the wild, first turning into chrysalides and then emerging as adult butterflies, helping to stabilize declining populations of this species.
Though once abundant across the inland prairies of the Pacific Northwest, the Taylor’s checkerspot has now lost 99 percent of its grassland habitat to agriculture and urban development. The species is listed under the U.S. Endangered Species Act and, according to Xerces Society for Invertebrate Conservation, is in imminent danger of extinction.
The Oregon Zoo has raised nearly 19,000 checkerspots for release since joining the recovery effort in 2004. After more than a decade of working to increase the endangered butterfly’s numbers, Linders says the effects are becoming noticeable.
"We’ve started seeing Taylor’s checkerspots at locations where they haven’t been documented in years," Linders said. "It gives us hope for a species that is very close to disappearing completely."
In addition to the caterpillars that were released, 240 remain at the Oregon Zoo. Many will be released as adult butterflies sometime in May and a handful will be bred at the zoo and their offspring will be used for next year's release.
"It's interesting, when people think of endangered species in zoos and captive breeding programs, they think of putting them back into the wild. But in reality there is very little wild left to put animals back into," said Karen Lewis, conservation research associate at the Oregon Zoo. "But with something as small as a butterfly, we are able to actually make the difference and establish populations in the wild."
Lewis said that there is one site where the caterpillars were released for several years that now has a thriving population.
"We are getting good signs," she said. "We are confident that we are going to be able to reestablish this species."
The Oregon Zoo is a charter member of the Association of Zoos and Aquariums’ Butterfly Conservation Initiative, a collaborative effort among nearly 50 zoos and aquariums. The zoo works in partnership with and receives funding from the Washington Department of Fish and Wildlife and Joint Base Lewis-McChord and its Army Compatible Use Buffer program to rear checkerspots and release them into the wild. Additional project partners include the U.S. Fish and Wildlife Service, the Xerces Society and the Sustainability in Prisons Project administered through The Evergreen State College and Mission Creek Corrections Center for Women.
To learn more about the Oregon Zoo’s effort to save Taylor’s checkerspots and other imperiled Northwest species, visit www.oregonzoo.org/conserve/species-recovery-and-conservation.