1,200 endangered caterpillars to be released

Program aims to reestablish declining checkerspot populations in western Washington

For hundreds of endangered butterflies raised at the Oregon Zoo during the past year, naptime is over.

Zoo conservationists roused the half-grown Taylor's checkerspot larvae from their winter dormancy last month, transferring the 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.

Yesterday, Oregon Zoo staffers joined biologists from the Washington Department of Fish and Wildlife to release 1,219 of the growing caterpillars on prairies in central Washington, helping to reestablish populations of checkerspots where some of the region's best habitat remains. Another 165 larvae stayed behind and complete their transformation into adult butterflies at the zoo — a "rear guard" of sorts that will breed, lay eggs and produce caterpillars for release next year.

"The Taylor's checkerspot is one of the Northwest's most beautiful — and most endangered — butterflies," said Mary Linders, a species recovery biologist with WDFW. "Releasing caterpillars reared at the zoo is part of our ongoing effort to reestablish this imperiled species at sites where it was once abundant. 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 — over a span of warm, sunny days this spring — emerging as adult butterflies and unfurling for the first time their distinctive and colorful wings.

Rearing the rare butterflies comes with many challenges. One of the most difficult tasks is feeding the ever-munching larvae, which require vast quantities of specific plants. Thanks to the zoo's horticulture department, and a partnership with the Sustainability in Prisons Project and Larch Corrections Center, the checkerspot caterpillars are able to feed on narrowleaf plantain, one of the plants their species eats in the wild.

This level of care is crucial: 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. 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 succession, agriculture and urban development. And while the butterflies themselves are small, the restoration of their high-quality native prairie habitat also benefits a multitude of other species associated with this ecosystem.

The Oregon Zoo has raised more than 23,000 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. In 2016, the first of the reintroduced populations met the qualifications to be called "established," meaning it is likely to continue on its own without additional releases.

"That was the first time we'd been able to reestablish a self-sustaining population of checkerspots," Linders said. "It gives us hope for a species that is very close to disappearing completely."

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 and the Sustainability in Prisons Project administered through The Evergreen State College and Mission Creek Corrections Center for Women.

The Oregon Zoo is a service of Metro and is dedicated to its mission of inspiring the community to create a better future for wildlife. Committed to conservation, the zoo is currently working to save endangered California condors, Columbia Basin pygmy rabbits, Oregon silverspot and Taylor’s checkerspot butterflies, Western pond turtles and Oregon spotted frogs. Other projects include studies on black rhinos, Asian elephants, polar bears and bats.
The zoo relies in part on community support through donations to the Oregon Zoo Foundation to undertake these and many other animal welfare, education and sustainability programs. The zoo is located five minutes from downtown Portland, just off Highway 26 at exit 72. The zoo is also accessible by MAX light rail line. Visitors who travel to the zoo via MAX receive $1.50 off zoo admission. Find fare and route information online or by calling TriMet Customer Service at 503-238-RIDE (7433).
General zoo admission is $10.50 (ages 12-64), $9 for seniors (65 and up), $7.50 for children (ages 3-11) and free for those 2 and younger; 25 cents of the admission price helps fund regional conservation projects through the zoo’s Future for Wildlife program. A parking fee of $4 per car is also required. Additional information is available by calling 503-226-1561.

Media contact: 

Hova Najarian | 503-220-5714 | hova.najarian@oregonzoo.org