Wood frogs are once again singing, a springtime delight

On the last Sunday in April, I received a brief but exciting message. “Frogs are singing,” Barbara Carlson notified me.

Barbara and her husband Michael live along the bluffs above Anchorage’s coastal flats and they’d heard frog songs at “several places” in southwest Anchorage. This brief alert was enough to get me out and listening closely for the distinctive yet sometimes misleading voices of the only amphibians to inhabit the Anchorage area, wood frogs.

While many researchers and naturalists liken those songs to a “duck-like quack.” But to my ears, they more closely resemble a hiccupy gulp. Still, I can understand why someone unaware of the frogs’ presence might believe a pond of singing frogs to instead be occupied by mallards.

As recognizable as the primeval calls of sandhill cranes, the honking of geese, or the cheery whistled songs of robins, once a person learns to identify the songs of wood frogs, they become among the most distinctive sounds of springtime.

On the evening of April 24, the same day I received Barbara’s message, I headed to some wetland pools near Earthquake Park, not far from where I live. Though they were brief and tentative, I did hear the first frog songs of spring, one more reason to celebrate the season. And the animals themselves.

The only amphibian to inhabit most of our state wood frogs’ range extends from the Southeast Panhandle deep into the Arctic. Lithobates sylvaticus has evolved a most unusual mechanism to survive the far north’s long, harsh winters: the bodies of wood frogs freeze solid as temperatures drop to 32 degrees Fahrenheit and below.

These amphibian wonders have small, handsome bodies despite males measuring roughly two to three inches long and females measuring slightly larger than males. They range in color from brown or bronze to a bright, coppery orange, speckled with dark spots. A dark band crosses their faces, the species’ so-called eye mask. And beneath that mask, a thin whitish “lip line” runs across their mouths.

Once they’ve thawed in warming temperatures, wood frogs hop to the nearest body of water, where they seek out mating partners. And that’s where the songs come into play: in the build-up to breeding, male frogs engage in grand singing competitions, a kind of courtship ritual, I suppose, intended to impress the females they’re pursuing.

Knowing that at least some of Anchorage’s frogs had begun to announce their seasonal rebirth, I decided to check out a network of ponds within a long stone’s throw of the Coastal Trail. The ponds are located about 3½ miles from Point Woronzof and 2 miles from the Kincaid Chalet. What makes these ponds special, at least to me, is that they are the temporary vernal home of many, many wood frogs.

Besides hosting a large population of frogs, these ponds are usually among our city’s first bodies of water to completely melt in spring. So if you time your visit right, you can hear a grand chorus of amphibian love songs.

On the afternoon of April 25, I headed down the Coastal Trail with my enthusiastic walking companion, Denali, toward what I’ve come to call the Kincaid Frog Ponds. Before we reached the ponds, I knew we’d hit it right: a chorus of overlapping frog calls reached my ears.

The more frogs that are calling, the more strongly males have to project their voices to be heard by potential mates. So, my ability to hear their voices from a few hundred feet away, with dense thickets separating me from the ponds, suggested an abundance of frogs were already raising their voices in celebration of the sexual activities ahead.

Denali and I hurried down to the nearest pond, where the males were engaged in a loud and riotous songfest. They did go quiet at my dog’s initial splashing approach, but after a short while, the frogs began to sing anew.

I’ll note here that wood frog researchers who track such things have developed a “calling index” to qualitatively measure the relative abundance of singing frogs. That scale goes from 0 (no frogs calling) up to 3, a full chorus in which calls are “constant, continuous and overlapping.”

On this day I’d say the calls were at the top of the charts. But they didn’t quite match the peak of calling that I heard last year at these ponds, which I then rated “off the charts,” the most riotous song-making I’ve ever heard by Anchorage’s frogs.

In both 2019 and 2020, I heard frogs calling toward the upper end of the scale in late April at these ponds. But in neither of those years had they reached the crescendo that I witnessed last year in early May when the frogs (to quote myself) were “going bonkers.”

The other thing I’ve noticed about wood frogs: at the peak of mating, they throw all caution to the wind. Under normal conditions, wood frogs tend to be secretive, elusive, and easily spooked critters that dive (or hop) for cover at the slightest approaching noise. But on the few occasions that I’ve witnessed them at their orgiastic climax, the frogs have seemed totally oblivious to my presence. Or perhaps they simply didn’t care.

They continued to sing (and in some instances, mate) even when I walked or talked. And none dived for cover. But, of course, amphibians are hardly the only creatures driven to distraction by sex, and there’s good reason for that. Wood frogs are considered “explosive breeders.”

That brings us to another remarkable thing about wood frogs: adults spend only a few weeks of each year immersed in water. Once mating is done, they swim for land and rapidly disperse. They’ll spend the remainder of spring, summer, and fall hopping and feeding in local woodlands, wetlands, and meadows. And then they’ll find a protected place, for instance, huddled beneath a pile of leaves, where they’ll spend the winter in a kind of suspended animation.

Thousands of wood frogs will thus be hopping among us over the next several months, largely unnoticed, in places most people wouldn’t suspect. In fact, it’s my sense—repeatedly confirmed by conversations with random individuals—that many human residents of Anchorage have no idea that wood frogs share the landscape with us, as we go about our busy lives oblivious to the presence of these small wonders.

Anchorage nature writer and wildlands/wildlife advocate Bill Sherwonit is a widely published essayist and the author of more than a dozen books, including “Living with Wildness: An Alaskan Odyssey” and “Animal Stories: Encounters with Alaska’s Wildlife.” Readers wishing to send comments or questions directly to Bill may do so at akgriz@hotmail.com