Conservationists transport Oregon silverspot caterpillars to slopes of the coast range
Summer is in full swing, and some of the Oregon Zoo's tiniest residents are headed for the mountains of Oregon's coastal range.
Throughout the month of July, zoo butterfly conservationists and colleagues from the Oregon Parks and Recreation Department, the U.S. Fish and Wildlife Service, and Seattle's Woodland Park Zoo will release more than 1,600 Oregon silverspot caterpillars at five sites throughout the temperate coastal mountains in an effort to stabilize declining populations of this threatened species.
The caterpillars began their journey as part of the zoo's imperiled butterfly recovery program. Each summer, a small number of female silverspots are collected by field biologists and brought to the zoo lay eggs. The eggs hatch into tiny larvae (caterpillars), which are kept safe during their winter dormancy.
In the spring, they wake up to a leafy meal and grow quickly. When the weather grows warmer, the zoo and its conservation partners transport the caterpillars to field sites to bolster the remaining populations.
The release sites are chosen carefully based on the presence of a rare flower — the early blue violet. Early blue violets are the main food source for the silverspot caterpillars as they mature into adult butterflies, and the Oregon coastal range is one of the few remaining areas where early blue violets grow in large enough quantities to sustain a butterfly population.
Listed as threatened under the federal Endangered Species Act, the Oregon silverspot was once common in coastal grasslands from Northern California up into British Columbia. Today, due to habitat loss and the disappearance of its host plant, just four isolated populations remain: three in Oregon and one in California.
"If it weren't for this recovery effort, it's likely that three of the remaining silverspot populations would now be extinct," said Travis Koons, who oversees the Oregon Zoo's butterfly conservation lab.
Funding for the Saddle Mountain reintroduction project was provided by the USFWS Cooperative Endangered Species Conservation Fund. Additional support is provided by Coffee Creek Correctional Facility, the National Park Service, the North Coast Land Conservancy Trust, Oregon Parks and Recreation, Washington State University, Oregon DOT, Pacific University, The Nature Conservancy, Center for Natural Lands Management and Pelican Brewery.
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. To learn more about the Oregon Zoo's effort to save Oregon silverspots and other imperiled Northwest species, visit oregonzoo.org/recovery.
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.