At the edge of a pond in Salmon Creek Park, Peter Ritson picks up a pacific tree frog and gently turns her over on her back. Children wearing rubber boots crowd around him in a circle.
“The way I know she’s a female is you can see her throat is the same color as her belly,” he says. “I will show you one more cool thing. If you look right in her hip there, you might see little spots. Those are her eggs,” he shows them.
Ritson, a biologist with Portland Community College, is one of the leaders of the 14th Vancouver Critter Count, an annual reptile and amphibian survey organized by the Water Resource Education Center. The goal of the survey is to monitor changes in the distribution of species over time.
He adds the squirming female tree frog to the list of species his group has found in the ponds and wetlands that border the park today: red-legged frogs, long-toed salamanders, and garter snakes.
The most exciting discovery, for both the children and the biologist, was a quivering egg mass, the consistency of firm jello. Each egg held a larva of a northwest salamander, a species Ritson says is somewhat unusual to find in urban ponds.
The kids also spot something less desirable: a bullfrog. Non-native species like the bullfrog are one of the many reasons native frog populations in the Northwest are declining.
Wordwide, climate change and diseases like the chytrid fungus threaten thousands of amphibian species with extinction.
Habitat loss is another key reason frogs are vanishing. Vancouver is one of the fastest-growing cities in the Northwest. The range of two amphibians, the Oregon Spotted Frog and the Western toad, has declined in Clark County.
Ritson says it’s important to monitor amphibians and reptiles to track how their populations are responding to development in the area.
Standing in front of the children, he points out a parking lot across from the wetland.“I think we can coexist. We can have our cars, we can have our buildings, but if we’re thoughtful about it, we can also have our wildlife. But it takes thought and planning and it is expensive,” Ritson says.
The data gathered during the Vancouver Critter Count survey will be entered into a database called Nature Mapping, run by the University of Washington and the Washington Department of Fish and Wildlife. Citizen reptile and amphibian counts also take place in Gresham and in Portland.