Zoo, partners return endangered turtles to wild

Zoo-reared northwestern pond turtles are released in the Columbia River Gorge

Nine northwestern pond turtles shell-ebrated their graduation from the Oregon Zoo’s turtle lab this week. With the help of volunteers, wildlife officials and members of the Zoo Apprenticeship Program, care staff returned the endangered reptiles to the Columbia River Gorge.

Since last fall, the turtles have basked in the warmth and light of a simulated summer at the zoo’s conservation lab, growing large enough to have a fighting chance in the wild. Now they’re ready for the real thing.

As part of a regional recovery project, conservation scientists “head-start” newly hatched turtles gathered from wild sites, nurturing them at the zoo for up to a year.  

“The turtles live in summer conditions year-round in the lab,” said senior keeper Sara Morgan. “They grow quickly and reach the size of adolescent turtles in about nine months. This gives them a better chance of surviving in the wild.”

Keepers prepare the turtles for life outdoors by giving them plenty of time outside to acclimate to changing temperatures. Once the turtles reach about 50 grams (a little less than 2 ounces), they’re taken to ponds along the Columbia River Gorge, where a team of conservationists returns them to their natural habitat and monitors them for safety. In one study, scientists estimated that 95% of the turtles released back to sites in the Gorge survive annually.

“The larger they are, the safer they are from predators like bullfrogs,” Morgan said.

The American bullfrog, native to the eastern United States but considered invasive here, is the largest frog species on the continent. It can tip the scales at more than a pound and has been driving pond turtles and a host of other small, vulnerable aquatic species to the brink of extinction.

The northwestern pond turtle, also known as the western pond turtle, is listed as an endangered species in Washington and a sensitive species in Oregon. Two decades ago, the turtles were on the verge of completely dying out in Washington, with fewer than 100 of them left in the state. Since then, more than 1,600 zoo-head-started turtles have been released.

“This is a critical time for these turtles,” said Morgan. “We need to get their population numbers up if we’re going to help save the species.”

The Western Pond Turtle Recovery Project is a collaborative effort by the Oregon Zoo, Woodland Park Zoo, Washington Department of Fish and Wildlife, U.S. Fish and Wildlife Service, Bonneville Power Administration, U.S. Forest Service and other partners.