10/1/02

PORTLAND -- Rare silverspot butterfly pupae, nurtured behind the scenes at the Oregon Zoo, have recently been released at the Nature Conservancy's 280-acre Cascade Head Preserve, north of Lincoln City.

The zoo, in partnership with the Nature Conservancy and the US Fish and Wildlife Service (USFWS), hopes to stabilize the butterfly population on the Oregon coast, which is in grave decline.

The Oregon silverspot butterfly is listed as threatened under the U.S. Endangered Species Act. It was once found in coastal grasslands from northern California to southern Washington, but has disappeared from all but a handful of sites along the Oregon coast due to habitat loss and the disappearance of its host plant, the western blue violet.

During the preceding decade, monitoring at Cascade Head revealed a dramatic decline in the number of butterflies seen flying. In years prior to 1992, average numbers exceeded 1,000 adults, but in 1998, only 57 of the butterflies were found.

In 1999, in response to the dramatic decline in the butterfly population, the Oregon Zoo, the Nature Conservancy, US Fish and Wildlife Service (USFWS) and others took action to save the threatened species and its habitat.

"Each larvae was only about two millimeters long," said Mary Jo Anderson, Oregon Zoo butterfly keeper. "When you observe them under a microscope, you can see that they are a perfect miniature caterpillar."

Debbie Pickering, Oregon coast stewardship ecologist for the Nature Conservancy describes captive rearing as a stopgap measure to keep the silverspot population stable until its habitat is restored. She added that butterflies are still being collected for captive rearing, which protects the young caterpillars from predation.

Currently, the Nature Conservancy, working collaboratively with US Forest Service, is restoring the native butterfly habitat through small, controlled burns. Scientist hope that by bringing back the western blue violet-which silverspot caterpillars depend on for food-the butterfly population can return to its historic numbers and ranges.

According to Vecchio, butterfly populations in the Northwest and throughout North America are in decline with 22 butterfly species listed as either endangered or threatened.

To address this problem, the Oregon Zoo in cooperation with the American Zoo and Aquarium Association (AZA) and 34 zoos and aquariums from around the country have formed the Butterfly Conservation Initiative (BFCI). The initiative program is designed to bring together non-governmental organizations and government agencies to aid the recovery of imperiled North American butterflies.

"Our cooperative conservation efforts are being seen more and more as part of the new zoo ethic," said David Shepherdson, Oregon Zoo conservation scientist. "It's becoming quite common for zoos to work outside their traditional captive programs to aid in the protection of animals in their natural habitat."

The Oregon Zoo is located on the MAX line, just off Highway 26, and is open from 9 a.m. to 6 p.m. (after April 1).

General admission is $7.50 (12-64), seniors $6 (65+), children $4.50 (3-11), and under 3 are free. Additional information can be obtained by visiting the zoo's web site at www.oregonzoo.org or calling 503-226-1561.