Fifteen tiny northwestern pond turtle hatchlings are spending their summer under heat lamps at the Oregon Zoo instead of facing invasive bullfrogs in the wild. The endangered hatchlings, retrieved from sites in the Columbia Gorge in June, will stay at the zoo's conservation lab until next spring, when they'll be released back into the ponds they came from — but only once they're big enough to have a real shot at survival.
Washington Fish and Wildlife biologists pulled the hatchlings from the gorge, with help from Jen Osburn Eliot and colleagues, who then transported the young turtles to the Oregon Zoo's conservation lab, according to The Portland Tribune. Guests can watch the hatchlings grow at the conservation lab inside the zoo's Nature Exploration Station, located near the tiger and red panda habitats. The threat driving this rescue effort has a name: the American bullfrog, the largest frog species on the continent, native to the eastern United States and now considered invasive in the Pacific Northwest. Weighing more than a pound, the bullfrog can eat pond turtle hatchlings directly from their nests, and it has helped push pond turtles and other small, vulnerable aquatic species to the brink of extinction, per the Tribune's report.
How a Head Start Beats the Bullfrogs
At the conservation lab, heat lamps and food keep the turtles from entering hibernation, so they live in summer conditions year-round rather than slowing down for winter. That trick lets them pack on roughly three years' worth of growth in under a year, per the Tribune. Once they reach about 50 grams — a little more than 2 ounces — they're as large as a typical 3-year-old turtle, and biologists return them to their home ponds, where they're monitored for safety afterward.
The payoff for that head start is striking. Conservation monitoring data cited by the Oregon Zoo shows that about 95 percent of zoo-raised northwestern pond turtles released into the Columbia River Gorge survive their first year in the wild, compared with drastically lower survival odds for hatchlings that never leave the nest. The zoo released 22 head-started turtles into protected gorge ponds back in May, just weeks before this newest cohort of hatchlings arrived at the lab.
A Species That Nearly Vanished
The stakes behind this work run deep. Washington's wild western pond turtle population bottomed out in 1990-1991 at roughly 150 individuals across just two isolated sites in the state, according to the Washington Department of Fish and Wildlife. Jen Osburn Eliot told the Tribune that western pond turtles numbered fewer than 100 in Washington two decades ago and were on the verge of dying out entirely. Every hatchling now matters enormously to reversing that trajectory, Osburn Eliot said, adding that the number of turtles in the wild must increase to save the species from extinction.
That near-collapse is why the Western Pond Turtle Recovery Project has run since 1991, a collaborative effort founded by Woodland Park Zoo and the Washington Department of Fish and Wildlife, with the Oregon Zoo joining in 2000. The partnership now also includes the U.S. Forest Service, the U.S. Fish and Wildlife Service, and the Bonneville Power Administration, per the Oregon Zoo. Combined, the partner zoos have head-started and released more than 2,300 turtles into protected habitats region-wide, and the Oregon Zoo alone has released more than 1,500 of its own zoo-head-started turtles, the Tribune reports.
Progress Measured in Ponds and Populations
That decades-long push has paid off in geography as much as numbers. Head-start releases and land management partnerships have expanded Washington's western pond turtle footprint from two historic sites to six protected population locations across the Columbia River Gorge and South Puget Sound, according to the Washington Department of Fish and Wildlife. The northwestern pond turtle — also known as the western pond turtle — is listed as endangered in Washington and as a sensitive species in Oregon, reflecting how differently the two states classify the same at-risk animal.
The regulatory picture is shifting at the federal level too. In October 2023, the U.S. Fish and Wildlife Service proposed listing both the northwestern and southwestern pond turtle as threatened under the federal Endangered Species Act, citing habitat loss, drought, and invasive species. A similar head-start effort is underway further south: Hoodline previously reported on a San Gabriel turtle rescue after wildfire, where southwestern pond turtles face the same combination of invasive bullfrogs and a shell-devouring fungus called Emydomyces testavorans that has been documented afflicting wild pond turtles across Washington and Oregon as well, according to the Shedd Aquarium.
Bullfrogs aren't the only invasive competitors in Oregon's waterways. Dumped former pet turtles, including red-eared sliders and common snapping turtles, have established wild breeding populations that compete with and prey on native turtles — a problem serious enough that Oregon banned importing, transporting, or selling those species back in 1996, per the USDA Forest Service. For now, the 15 hatchlings growing under the Oregon Zoo's heat lamps represent one more incremental step in a recovery effort that has already stretched across three and a half decades, with next spring's release marking the next test of whether this generation can beat the odds their wild-born counterparts never had.
