Hundreds of endangered frogs raised at Northwest Trek Wildlife Park in Eatonville, Pierce County, and at the Oregon Zoo recently hopped back into the wild.
In an effort to establish a new population of northern leopard frogs, Northwest Trek keepers released nearly 300 of them in the Columbia National Wildlife Refuge in Grant County at the end of August, the wildlife park said in a news release.
Northern leopard frogs were once abundant throughout North America, but have rapidly disappeared from their native ranges in Washington, Oregon and western Canada due to habitat loss and degradation, disease, nonnative species and climate change, the wildlife park said.
The species has been listed as endangered in Washington since 1999. With only one known wild population remaining in the state, this marks the beginning of a long path to recovery for the frogs, the wildlife park said.
“We are at a critical point for this species,” said Lindsay Nason, a Washington Department of Fish and Wildlife biologist. “We’re working to bypass those threats through critical growth stages and establish a new population of northern leopard frogs in the region.”
In early spring, the department collected northern leopard frog eggs and took them to Northwest Trek and the Oregon Zoo to grow from egg masses to tadpoles to froglets.
“The frogs are raised in a controlled environment where keepers monitor everything from their water quality and temperature to the amount of food they receive,” said Marc Heinzman, Northwest Trek’s zoological curator.
Keepers prepared the frogs for life in the wild by giving them food such as crickets to encourage their natural food-scavenging behaviors. Once the frogs were big enough, keepers and a biologist from the Department of Fish and Wildlife took them to their new home in the Columbia National Wildlife Refuge ponds, the wildlife park said.
By giving the frogs a head start and raising them “free of predators,” they have a better chance of survival in the wild, Heinzman said.