On cold winter nights in Portland, near the edge of the Linnton neighborhood, a highway cuts directly through the migration path of the city’s northern red-legged frogs. Generally found in forested uplands, these tiny frogs travel seasonally through their habitat to breed in shallow ponds. Portland’s northern red-legged frog population resides in Linnton, close to Forest Park, and journeys down a large hill and over Highway 30 to their pond.
In early 2014, Rob Lee, one of the co-founders of the Linnton Frog volunteer organization, stumbled upon hundreds of tiny frogs on the road near his home. “They were everywhere. On a Monday night, the traffic [was] really heavy, and the frogs just [didn’t] have a chance,” Lee explained. The next morning he found around 65 dead frogs on the very same street. “I wrote on my calendar ‘frogs,’ … and I found [biologist] Sue Beilke, who told me about [them]. Then in December, we had a meeting with maybe eight people and several biologists, and that’s when it got started.”
The Linnton Frogs volunteer program facilitates the Harborton Frog Shuttle, which focuses on two sites: Harborton Drive, which is directly below the forested uplands, and is the first road the frogs cross in their journey; and Marina Way, the last obstacle before the Harborton wetland. Volunteers collect and transport frogs from the forest to the wetland during the early December to late February breeding period. 11 years since its start, Lee’s program is still going strong, with seven volunteer crews and thousands of frogs saved.
In hopes of saving some frogs, I made the trip to Harborton Drive. It was nearing the beginning of the night’s volunteer shift, the sky darkening, when I pulled into a small road by the forest to meet with Lee. The cement was damp, but not damp enough; volunteers have to yield to the frogs’ schedule, not the other way around, which means that if there’s no rain or the temperature is above 50 degrees Fahrenheit, the frogs won’t show. This was the case that night, the night of my first volunteer attempt. Though there were no frogs, the visit was quite pleasant; I spent the time listening to Lee’s stories and gathering information for my next visit.
Still, my newly heightened interest in frogs was left with more questions than answers. Dr. Marc Hayes, a retired research scientist for the Washington Department of Fish and Wildlife, helped me explore the lives of these migrating frogs. “Northern red-legged frogs make a big move. They move [0.5 to 1.2 miles] from wherever their breeding ponds are into forested uplands,” he explained. “They can move as far as … three and a half miles.”
After they’ve bred, the fear of the predators that live in the wetlands compels them to move back up to the forest. “Raccoons and skunks and various other things do a constant circuit of the ponds in order to get food,” Hayes stated. The wetlands are an open area, which makes it harder for the frogs to hide from threats, whereas the forested uplands provide a cover of sword ferns and thorny bushes. The most significant threat of mortality remains vehicles, encountered when crossing open areas, especially roads and highways.
The Linnton Frogs’ volunteer capabilities may seem limited, but it has saved thousands of frogs over the last decade. “It has also provided education and [the] opportunity to learn about frogs to hundreds of community scientists,” wrote James Holley, an amphibian researcher, in his 2022 “Harborton Wetland Amphibian Assessment.” Holley explained in his findings that the northern red-legged frog habitats in Portland have been severely damaged or destroyed, leaving the Harborton wetland as the “closest large, intact, high-quality breeding habitat suitable for pond-breeding amphibians to serve this large population.” However, the wetland has been disconnected from the upland habitat in Forest Park by Highway 30. Despite the disruption to their path, the frogs still have to migrate; large casualties to their population come from crossing the highway.
In his assessment, Holley proposed a long-term solution: a wildlife highway undercrossing. “Finding a way for frogs to both follow their natural inclination to move with no disruption to human traffic is essential,” stated Holley. Since the assessment was written in 2022, a concept has been adopted by multiple organizations, including shuttle volunteers, to build an underpass for the thousands of frogs that cross every winter, according to the Oregon Wildlife Foundation. The next step is raising awareness and advocating for funding. “Additional funding sources of up to $1 million will have to be found to build the undercrossing,” Holley explained. Though other ideas have been introduced, such as habitat improvement in Forest Park, advocates like Holley have their hearts set on building a permanent solution that is more authentic to the frogs’ natural migration pattern.
The second time I visited the Linnton Frog Shuttle was at the Marina Way site, above the wetlands where the frogs bred. Though it was too cold for the frogs’ preference, it had been weeks since they had last moved and many were stuck in the wetlands after breeding. After signing a waiver, I met with Holley, the leader of the night’s crew, who assisted with headlamps and reflective vests. We made our way to a long fence along the side of the road, cushioned with tarps to stop the frogs from crossing into the road. Holley explained the system of the buckets holding the fence down: each red bucket marked a different section assigned to volunteers to monitor, and the white buckets held frogs. After five minutes, I was steadily stationed at Section Two. My headlamp switched on, I searched the tarped fence and the bushes behind it.
The red-legged frogs were masked by their speckled skin, making them tricky to spot. Many were out of reach or spooked into untouchable, thorn-riddled areas. Half an hour in, I spotted one near my feet, a small amphibian blindly searching for an exit against the tarp. He was slow, which meant he would be easy to grab, and — after ample encouragement — I picked him up and gently placed him in a white bucket. Feeling victorious, I caught another. After an hour and a half of finding frogs, the crew counted the small creatures and loaded the white buckets into their cars for the drive to Forest Park. It was dark, cold enough to barely see past my cloudy breath, and my fingers were coated in slime, but the feeling of saving frogs was thrilling and unforgettable.
Volunteering for this cause is low risk with an incredibly high reward. Though this organization has saved thousands of frogs, its impacts lack permanence. As their habitats are not properly protected, frogs are dying. The smell of factory work off Highway 30 trails down to the wetland, where the tarped frog fence is stationed directly by train tracks. The road to the Harborton volunteer site is built over animal habitats; what was once completely forest has been affected by Portland’s urban sprawl. Though the issue has been tended over the last 11 years, increasing awareness of the frogs’ peril is necessary to establish a permanent solution preserving the lives and precious habitats of these amphibians, allowing humans and frogs to peacefully coexist.
