From The Oregon Zoo
Earlier this month, the zoo and its conservation partners rounded up turtle hatchlings from southwest Washington lakes to rear in a protected environment until they are big enough to be released back into the wild. Visitors can now view nearly 40 hatchlings –– each a bit larger than a quarter –– at the zoo’s conservation station, located in the Cascade Stream and Pond Building.
Over the next nine months, zoo staff members will monitor and weigh the rare turtles as they grow. Once they reach a suitable weight of more than 2.5 ounces, the turtles will be returned to the wild and monitored for safety.
“When we release the turtles, they’re big enough that predators like non-native bullfrogs are no longer a threat,” said David Shepherdson, the zoo’s conservation biologist. “The months the turtles spend at the zoo give them a real edge — scientists estimate that 95 percent of the turtles we’ve released into the Columbia River Gorge have survived.”
Twenty years ago, western pond turtles had nearly disappeared from Washington, their native habitat, with only 150 turtles left in the wild. Today, researchers estimate there are about 1,600.
Habitat degradation and disease continue to endanger the species, but the biggest threat to fragile baby turtles is the bullfrog. Native to areas east of the Rockies, this nonindigenous frog has thrived throughout the West, driving pond turtles and a host of other small, vulnerable aquatic species to the brink of extinction.
“The Western Pond Turtle Recovery Project is a collaborative effort of the Oregon Zoo, Woodland Park Zoo, Washington Department of Fish and Wildlife, U.S. Fish and Wildlife Service, and the Bonneville Power Administration,” said Kim Smith, zoo director. “We’re proud to be a partner in the effort to help restore the western pond turtle population and its habitat in the wild.”
Every summer, wildlife recovery biologists monitor female turtles in the field to determine where they will dig their nests. Once the turtles have laid their eggs, workers cover the nests with wire “exclosure” cages that help prevent predators from eating the eggs. The eggs are then allowed to incubate naturally, and hatchlings are collected in the fall.
The hatchlings are barely the size of a quarter when they are taken to the Oregon Zoo and the Woodland Park Zoo. Unlike wild turtles, the zoo turtles are fed and kept warm throughout the winter, so by their summer release, the 10-month-olds are as big as wild 3-year-old turtles.
“We make sure our turtles can hold their own before releasing them into the wild,” Shepherdson said.