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What’s that sound? Ptarmigan? No, it’s raucous, lovesick Alaska wood frogs.

  • Author: Bill Sherwonit
  • Updated: June 30, 2017
  • Published June 30, 2017

Wood frogs are the only amphibians to inhabit Alaska north of the Southeast Panhandle region. And they survive long, harsh winters by entering a state of suspended animation. In essence, their bodies freeze solid.

Twice this year I've witnessed marvelous choral performances at Anchorage-area ponds. Which of the two was more amazing is hard to say; each seemed something of a miracle. Yet both went largely unnoticed, for different reasons.

Wood frogs have been studied at UAF for more than 50 years. (Ned Rozell)

The first pond event occurred the evening of April 29. On something of a whim — and a hunch — I grabbed my mixed collie, Denali, and drove to Point Woronzof. It was close to 9:30 when I pulled into the parking lot, which had filled to overflowing with vehicles and people. Never have I seen this place so lively, though I rarely go there on a weekend night. The evening itself was a big part of the reason. It had to be one of the loveliest to grace Anchorage all spring: mild, still and radiant in the late-evening sunlight. It seemed clear the sunset was becoming a beauty, with layers of clouds above the Sleeping Lady glowing golden.

Still, I hadn't come for the sunset or the splendor of the evening, though those surely added to my delight. While nearly everyone else seemed pulled toward that gorgeous western sky, I headed for the small, humble pond that sits largely unnoticed near the Point Woronzof parking lot. Even before leaving my car, I knew an incredible spectacle awaited me, because I could hear a multitude of loud voices emanating from the water.

My timing couldn't have been better. The pond was rich with the songs of lovesick wood frogs.

Who knew?

Since I first learned of their presence in the late 1990s, it has always seemed wondrous to me that we share the Anchorage landscape not only with moose, bears, lynx and many species of birds, but also with multitudes of small amphibians. In spring and summer it's likely that thousands of them hop and swim among us, mostly unnoticed, in places most people wouldn't suspect.

A large portion of the city's human residents probably have no idea our community is home to frogs. Heck, I love our wild neighbors and pay more attention to them than the average person, and I'd been settled in Anchorage for 16 years before I learned that wood frogs live here too.

There's so much about the lives of Alaska wood frogs that amazes and delights. They're the only amphibians to inhabit Alaska beyond the Southeast Panhandle region, residing even north of the Arctic Circle. And they survive Alaska's long, harsh winters by entering a state of suspended animation. In essence, their bodies freeze solid — and then thaw again in spring (a story itself).

Another thing I love about Rana sylvatica — and what drew me to the Point Woronzof pond that April evening — is that they're "explosive" breeders. Their mating season is very short. And at its peak, male frogs tend to go bonkers, announcing their intentions — and, I suspect, their jubilation — to the world. When this happens, they sing. Or call, if you prefer. They do so in voices that have been likened to the quacking of ducks, though to my ears their songs more closely resemble hiccupy gulps easily distinguishable from waterfowl.

However they sound, at the peak of mating season male wood frogs raise their voices in grand singing competitions.

Researchers who monitor wood frogs have developed a "calling intensity" index to measure the number of calling frogs, from 0 (no calls) to 3 (a full chorus of many calls, continuous and overlapping). Once before, years earlier, I'd stood at the Point Woronzof pond when the frogs' performance went way off the charts. My notes described it as "a riotous racket," the most amazing wood frog serenade I'd ever heard.

Yet on this April night, the frogs seemed to exceed even that earlier explosion of song. They were absolutely raucous, raising their voices in a frenzied expression of the breeding drive that must have been surging through their tiny bodies.

In my experience, wood frogs are normally secretive, elusive and easily spooked critters. But on this night — as on that afternoon years earlier — they seemed to abandon all caution. When I quietly walked to the edge of the pond, the frogs continued both their singing and their pursuit of one another. Along one section of the pond where the frogs were concentrated, the water was filled with a multitude of tiny splashes and rippled water.

For several minutes, I was pulled into the amphibians' world, spellbound by both their voices and physical presence.

Amphibian recording

When I finally looked up, I saw that I was the only person paying attention to the frogs. Not surprising, really, especially on this glorious night.

The sunset was too lovely for even someone entranced by frogs to ignore. But before leaving the pond to turn my attention to the sky, I decided to record this enthralling amphibian performance. I pulled out my iPhone and touched the video application, uncertain how well it would capture the frogs' songs. The results far exceeded my expectations. Now I would have evidence to share with friends.

Then, accompanied by Denali, I walked over to the edge of the bluff, where a cross-section of Anchorage residents celebrated another natural spectacle. Dozens of people walked or sat on the beach below and many others stood atop the bluff, mesmerized by the unfolding sunset, the slow darkening of the sky and the deepening of the colors that imbued the clouds floating above Mount Susitna, from gold to orange to rose and finally a deep crimson. There was a palpable buzz, a collective, electric mood among the people gathered here. I felt it. I shared it. And yet … I was drawn back to the frog pond.

I again stood in the company of a grand chorus, my heart pumping, a smile creasing my face. What a night.

A water strider moves off a reed as a wood frog rests in a small pond at Point Woronzof in West Anchorage on April 21, 2016. Wood frogs in Alaska freeze almost solid in the winter. Their hearts stop beating the as they hunker down in the forest floor litter. Water striders are able to move across the surface of bodies of water. (Bob Hallinen / ADN archive)

Timing is everything

Several weeks later, I hiked into the Chugach Front Range with my girlfriend, Jan, and our two dogs, and headed toward a small tundra pond a few thousand feet higher than Point Woronzof. Finding seats on the greening alpine tundra, we settled in to enjoy another chorus of frogs. This early June performance was less riotous than what I'd observed in April, yet impressive in its own way.

To briefly backtrack: Three evenings after the Point Woronzof pond echoed loudly with frog song, I'd accompanied Jan there hoping for an encore. We heard a single frog call a few times. Otherwise silence. More than that, we saw hardly any signs of frogs. It's as if they'd disappeared, which may be close to what happened. Adult wood frogs begin to disperse onto land soon after mating, the males departing first, followed by the females after they've deposited their eggs. It can happen that fast. One night a full-throated chorus. A few nights later, silence.

Up in the mountains, the singing frogs seemed much more sensitive to any disturbance. Perhaps they hadn't yet reached a state of careless, frenzied lust. The frogs quieted as we approached, so we found a place to sit and remained as still as possible (that's not entirely possible with two dogs).

It still seems remarkable to me that frogs inhabit any part of the far north. But the idea that they'd be alpine animals? That's almost impossible to imagine, until you find evidence. I "discovered" these frogs a couple of summers ago, while walking a high alpine ridge. Making my way along a rocky spine more than 4,000 feet in elevation, I suddenly heard what sounded like the hiccupy calls of frogs: Gulp … gulp … gulp.

That can't be, I told myself. I must be hearing willow ptarmigan. They have a deep, guttural call, sometimes described as a croaking, that's not too different from those of wood frogs, if you use your imagination.

Listening carefully, I heard another gulp. And another.

Nope, those weren't ptarmigan. They were wood frogs. I felt certain of it. That has to rank among the strangest experiences I've ever had, to listen to the songs of wood frogs while traversing a high mountain ridge. Turning my attention toward two small alpine ponds in the tundra basin below, I figured the calls had to be coming from there. Turned out I was right.

That first summer I spotted a handful of frogs in the pond. They were quick to dive, if sensing any movement outside the pond. At least that's my interpretation.

On this year's June visit, we initially saw only three frogs, while looking from a distance with binoculars. But after we'd settled onto the tundra, more began to appear. Eventually we counted 11 frogs and almost certainly more occupied the pond. Most that we watched rested at the surface in a relaxed pose, back legs extended and splayed.

It wasn't long before they began to sing, tentatively at first but then, as more frogs joined in, more robustly. I'd say between 2 and 3 on the calling index. There were periods of constant calling, with some overlap of voices.

Speaking softly, Jan and I cheered the singing and, I think it's fair to say, we felt cheered by it.

An adult wood frog with a radio transmitter super-glued to its back is ready to be released by graduate students as part of their class in the study of the frogs’ ability to withstand freezing during the winter. (Bob Hallinen / ADN archive 2004)

As at Point Woronzof, I made a video recording to document the singing frogs. Few people I know are aware of these Chugach tundra frogs and that may be a good thing. Because they're less common, they may be more vulnerable to disturbance than city frogs.

In another week or two, someone happening upon the tundra pool would likely find little or no sign that it's a frog pond, unless she happened to notice clusters of eggs or, sometime later in the summer, the shadowy figures of tadpoles hugging the bottom. Their parents, meanwhile, will have scattered across the tundra, perhaps now and then surprising a hiker or hill climber. And isn't that too a marvelous thing?

Anchorage nature writer Bill Sherwonit is the author of more than a dozen books, including "Animal Stories: Encounters with Alaska's Wildlife."

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