PORTLAND, Ore. –– Endangered Oregon spotted frogs raised from eggs to tadpoles at the Oregon Zoo were released into the wild this month, as part of a joint project with the Washington Department of Fish and Wildlife.
More than 1,200 frogs were released in the Dailman Lake area at Fort Lewis, including about 100 that reared at the Oregon Zoo. The protected site contains one of the largest relatively intact wetlands remaining in the Puget Lowland.
“It is suitable for reintroduction because its diverse wetlands are connected to a stream system that can sustain a frog population,” said Jim Lynch, wildlife biologist at Fort Lewis.
The frogs had been collected as eggs from other wetlands by wildlife biologists, then placed at the Oregon Zoo, Woodland Park Zoo, Northwest Trek and Cedar Creek Corrections Center.
They are now large enough to avoid some predators that eat tadpoles.
Considered endangered in Washington and Canada, threatened in Oregon and a candidate for listing under the federal Endangered Species Act, the Oregon spotted frog faces an uncertain future. Over the past 50 years, the frogs have lost almost 90 percent of their previous habitat.
“The Oregon spotted frog is the most threatened frog in the Pacific Northwest,” said Dr. David Shepherdson, Oregon Zoo conservation scientist. “It has special habitat requirements that bring it into proximity with bullfrogs.
Hundreds of Oregon spotted frogs have been released into Dailman Lake since 2008, when conservationists first introduced them at the site.
Researchers said some of the frogs released in previous years have been thriving and are now successfully breeding. It takes three years for Oregon spotted frogs to mature enough to reproduce.