Zoo-reared northern leopard frogs are released at Columbia National Wildlife Refuge
Hundreds of northern leopard frogs reared at the Oregon Zoo are hopping back into the wild this month, thanks to a collaborative effort to save one of the last remaining Northwest populations of this imperiled amphibian.
The froglets, which hatched from eggs collected by the Washington Department of Fish and Wildlife earlier this year, spent six months growing big and strong in a protected area at the zoo before being released into the Columbia National Wildlife Refuge this summer.
"They come to us as eggs, and we keep them safe and well-fed until they grow legs and can hop on their own," said Shelly Pettit, who oversees the zoo's frog-rearing efforts. "A big, healthy young frog has a much better chance of surviving in the wild than an egg or a tadpole."
The recovery effort is made possible by a partnership with the Washington Department of Fish and Wildlife, U.S. Fish and Wildlife Service, Washington State University and Northwest Trek Wildlife Park.
Once abundant throughout North America, northern leopard frogs are rapidly disappearing from their native ranges in Washington, Oregon and western Canada. In Washington, where the zoo-reared froglets were released, the species has been listed as endangered since 1999 and only one known population remains.
"We're at a critical point for this species," Pettit said. "After missing the 2020 season due to COVID impacts, we were very excited to produce a healthy group of frogs for this year's release."
Biologists attribute the frogs' decline to a combination of threats, including habitat loss, disease, predation by introduced fish species, pollution and climate change. By head-starting them, the zoo and its conservation partners are hoping to replenish the northern leopard frog population in the region.
Helping the frogs — and the wetland habitat they depend on — will benefit other species as well, conservationists say.
"Northern leopard frogs are an important indicator of water quality," said Emily Grabowsky, WDFW biologist. "If we can improve and conserve wetland habitat that is good for frogs, we will also benefit other species ranging from other amphibians to waterfowl and deer."
Funding for the northern leopard frog reintroduction is being provided through a competitive state wildlife grant awarded to WDFW from USFWS's Wildlife and Sport Fish Restoration program.