Nature on Trail: Frogs
By Janice Van Cleve
Most folks don’t usually think of mountains when they think of frog habitat, but the Cascades are loaded with these cute little amphibians. Chances are, if you were hiking this summer and saw one, it was a Pacific tree frog (pseudacris regilla), a Northern red-legged frog (rana aurora), or a Cascades frog (rana cascadae).
Contrary to their common name, Pacific tree frogs tend to be found on the ground or in shrubbery in all but the driest and coldest habitats. They breed almost anywhere—wetlands, ditches, seasonal pools, even deep tire ruts! Their tadpoles are usually the most common amphibian larvae at any breeding site. Some are so precocious that they can breed again right after metamorphosis! No wonder they range all over Washington State, from the Pacific coast to Walla Walla and their “ribbits” have been detected even during mild winters.
Pacific tree frogs are most easily identified by the sticky pads on their fingers and toes, a dark line that extends from their nose across their eyes to their shoulders, and a “Y” shaped mark on the top of their heads. They are small—less than 2 inches in length—with long legs for their size. The male has a darker throat than the female.
The Northern red-legged frog is much bigger than the Pacific tree frog, reaching 4 to 5 inches in length. This little fellow is conspicuously rusty, reddish-brown with pronounced folds running along both sides of its back from eyes to tail. It has big, bulgy eyes and the webbing on its longest toe does not extend past the first joint. The groin area—if you happen to get that close to see it—is mottled black on white.
The rana aurora has powerful legs capable of significant leaps. In fact, its cousin, the rana draytoni, is thought to be the frog Mark Twain spoke of in his tale of the “Leaping Frog of Calaveras County.”
This frog is found all over Western Washington in lowlands and foothills below 3,500 feet. It is more picky than the Pacific tree frog about its breeding grounds, preferring still waters. After breeding, it may migrate up to half a mile to seek out a nice, wet rivulet or creek side for the summer. In Washington, the Northern red-legged frog hibernates.
Another common frog which ranges all over the Cascade mountains is—appropriately enough—named the Cascades frog (rana cascadae). This is a 3- to 4-inch-long brown frog with black spots. It should not be confused with the Northern leopard frog (rana pipiens), which is found around Moses Lake. The Cascades frog prefers higher elevations above 2,000 feet in open coniferous forests, usually along running mountain streams. Its voice is a low, grating, clucking sound.
There are several other frogs in Washington State and a number of toads as well. Okanagan, Ferry, Stevens and Pend Oreille Counties are home to the Columbia spotted frog (rana luteiventris). This is a big, dark frog with upturned eyes and black spots with ragged edges. It has shorter legs relative to its body and full webbing on the toes. The Columbia spotted frog prefers higher elevations between 2,000 and 4,500 feet, very near ponds and streams. The common Bullfrog (rana catesbeiana) is a lowlands dweller in lakes and wetlands all over the state.
Often while hiking, my first indication of a frog is when it leaps off the path. I’ve found them on the steepest slopes and relatively far from water. These adventurous little creatures seem happy to roam all over the mountains as long as there is thick low-lying vegetation about. I always count it as good luck to find one on the trail. A mountain frog just seems to symbolize that it’s going to be a good day.
Photos: Top: Contrary to its name, the Pacific tree frog isn’t limited to trees. The 2-inch-long frog is found across the state in all but the driest and coldest of habitats. Photo by Kelly McAllister.
Center: The northern red-legged frog reaches 4 to 5 inches in length and is conspicuously rusty, reddish-brown in color. Photo by Kelly McAllister.
Bottom: The Cascades frog, from 3 to 4 inches long, prefers open conifer forests above 2,000 feet of elevation and is often found near mountain streams. Photo by Kelly McAllister.