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Letter from Skunk Hollow: Tree frogs signal environmental health and beauty

I take a plethora of sticky-footed amphibians as a welcome signal of environmental health, for frogs are often an indicator species whose decline points to environmental degradation.

The gray tree frog got into my hair, under my skin and on to my statuary.
MinnPost photo by Ron Meador

” … I arise in the morning torn between a desire to improve (or save) the world and a desire to enjoy (or savor) the world. This makes it hard to plan the day.” — E.B. White

My plan for this week was to write a world-saving kind of piece about renewable energy, or maybe copper-nickel mining in the north woods. But then the gray tree frog got into my hair, and under my skin.

Somehow I managed to pass the first 50-some years of my life without, as best I can recall, savoring one of these creatures up close. And this seems strange because I have always spent a lot of time outdoors, savoring natural things. Also, because tree frogs seem to be plentiful pretty much every place in North America where trees and puddles are present.

Or so I have now read in various naturalist accounts. I’ve also read, with skepticism, that the gray tree frog — the type most common in Minnesota and the upper Midwest — prefers to linger in treetops as high as 30 feet, comes down to ground level only to mate, and is active chiefly at night.

My own observation from a few years of living in the woods is that tree frogs are apt to turn up pretty much anywhere, any time.

tree frog on chair
MinnPost photo by Ron Meador
Frogs lounge on the patio furniture.

I’ve found them clinging to my windshield on a summer afternoon and in the cockpit of a sea kayak I thought I had sealed up tight.

They lounge on the patio furniture and hide in coils of garden hose. For several weeks we routinely found one, and perhaps the same one, day after day, holed up inside a Japanese lantern carved from lava rock, where the candle is supposed to go.

Sometimes they get into the house — to their sorrow and our regret, for eventually their perfectly preserved remains will turn up in the carpet, like a little golden raisin with legs.

Hitching rides on people and pets

I can’t see how they got there on their own locomotion. Perhaps they rode indoors on a shoe, a pants leg or a cat, employing the mucus that lets them bind their bulbous little toes to pretty much anything, including vertical sheets of wet window glass.

Last Friday afternoon I unrolled some hose to clean off a deck and found a good-sized tree frog soaking in a little puddle at the bottom of the caddy. Unperturbed by my intrusion, he stayed there for another hour, and another …

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Toward dusk I went out to put the hose back. It had grown windy enough to lift some fallen leaves, and I felt one catch in my hair. I lifted my free hand to brush it away and felt something … sticky. And dense.

First thought was that another newly hatched phoebe had fallen from the nest up under the eaves. But it was a tree frog, clinging now to the back of my hand and resting unruffled as I drew him up close for a better good look, then moved him away and snapped his picture with a cellphone.

Some people might find all these frogs a nuisance. Indeed, a TV station in Spokane recently produced a feature about a neighborhood where homeowners are disturbed by an apparent surge in the tree frog population.

“At first it was interesting and it was unique and fun,” one of them said. “It is starting to get where we’re concerned. We just see them everywhere…. I feel like it’s getting to the point where they’re becoming a nuisance.”

Why nuisance? Unclear from the story, but one wants to speculate that frogs in large numbers are somehow ickier than comparable hordes of, say, butterflies.

I will admit that once or twice, startled to find a frog in an unexpected place, I thought of the biblical plague and of the movie “Magnolia.”

A sign of environmental health

But in general I take this plethora of sticky-footed amphibians as a welcome signal of environmental health, for frogs are often an indicator species whose decline signals environmental degradation.

tree frog on leaf
MinnPost photo by Ron Meador
I take this plethora of sticky-footed amphibians as a welcome signal of environmental health.

Moreover,  the tree frogs have become a source of personal fascination.

In the first place, they are beautiful in the special way of creatures that are tiny and intricately buillt.

I’ve seen them smaller than a dime, never larger than a quarter. Like chameleons, they can change color to match their surroundings, from an emerald, leaflike green to a mottled, gravelly gray.

Their skins are bumpier than pond-dwelling frogs and this, in combination with their sometimes dirt-like coloration, makes them easy to mistake for toads. Until you see one hop onto window glass and stick like a suction cup.

Their call is haunting and, to my ear, not particularly reptilian – a trill more like the sound of big crickets or small squirrels, and loud for a creature so small.

Unless you have a microscope that enables you to count chromosomes, calls are the best way of distinguishing between the two types most common in our region: The gray tree frog has a trill often described as slower and more musical, and the Cope’s gray tree frog’s call is described as shorter and more raspy

In addition to secreting a temporary adhesive that 3M’s engineers might envy, tree frogs also manufacture their own antifreeze — a form of glycerol that protects their cells from bursting at subzero temperatures. According to naturalists at the University of Michigan, tree frogs have been known to survive below-zero spells of several days, with 40 percent of their body fluids turned to ice.

Nobody really knows how long they live in the wild, but in captivity a Cope’s tree frog has reached the ripe old age of 7.

They can’t fly, but when they jump or fall from a high place, they can move their bodies in midair to slow the descent and soften the impact.   

Students at DePauw University proved this by building a 12-foot-high wall painted like a ruler and then — I’m not making this up — shoving tree frogs, ground-dwelling cricket frogs and toads off the edge, filming their plunges to a pool of water.

The experiment was supervised by faculty and the school’s Animal Care Committee, and it proved that evolution has given tree frogs a “parachuting” skill — they extend their limbs in midair to glide.

Tolerant of the human presence

It  may just be my imagination, but they also seem rather sociable. Certainly they are less repelled by human presence and activity than toads and other frogs — less than most other wild animals, for that matter.

They don’t like to be picked up, of course, but they are easily nabbed. And a tree frog lifted from a chair seat to a table may settle down at my elbow for an hour or more while I read outdoors or write a letter.

Like most people, I am awed by the marquee species that wildlife biologists sometimes classify as “charismatic megafauna” — wolves and bears and bald eagles and such. There is undeniable fascination in their size and (usually) their predatory role. Also, often, in their sheer survival under pressure of human efforts to eradicate them.

But from a very early age I’ve been just as drawn to such common-as-dirt minifauna as fireflies and luna moths,  red squirrels and flying squirrels, fox snakes and snapping turtles and even Jefferson salamanders, which appeared to be colonizing the lower level of this woodland home the first few months I lived here.

I’m the hardly the first to make the point  but I often forget it, too, and I guess  the tree frog is just my most recent reminder that this world’s amazing wealth of wildlife is not some faraway feature, a vacation vista at the end of two-day drive or an all-day hike. Not even for the city dweller, which I’ve been for nine-tenths of my life.

It can be just as near as your elbow — indeed, as close as you care to look.

And when you least expect it, it can parachute into your hair.


Like many people, I’ve heard the E.B. White quotation at the top of this piece in a tightened and truncated form — reworked, perhaps, by people who felt they were omitting needless words. My source for this version is a profile by Israel Shenker, who visited White at his farm in North Brooklin, Maine, and wrote about it for the New York Times on July 11, 1969 (subscription may be required).

Interesting pages about the gray and Cope’s tree frogs are here, here and here.