It was during July of 1958 that I spent 17 of some of the most
exciting and memorable days of my life backpacking by myself on
Isle Royale National Park located in northern Lake Superior.
With all of my food, sleeping bag, rain poncho and camera
equipment on my back and really not a care in the world I
communed with the wilderness such as I had never done before.
There were some days that I enjoyed complete solitude by
neither meeting nor seeing a person. One of my most interesting
encounters was meeting up with and spending the greater part of a
day with David Mech back in the "boonies." He was a
graduate student studying with Dr. Durward Allen of Purdue
University and had arrived at the island to make preparations for
his now famous moose-wolf study. Today Dr. Mech is one of the
world’s highly respected wolf experts.
On another day I met a walking mailman from Ohio who had come
to hike the entire 45-mile length of the island during his
vacation. Naturally I thought it to be quite humorous that a
person who made his living walking would engage in the same type
of activity while on vacation.
However, as the years went by I found myself doing precisely
the same thing over and over. One occasion that comes to mind
occurred while I had used my day off from leading hikes at the
Ridges Sanctuary, where I was working at the time, to present an
evening program at the nature center on Washington Island. What
did I do on my day off? Naturally I took a long hike at the
Jackson Harbor Ridges!
But that day remains vividly locked in my memory. The
pristine preserve was isolated and virtually fog-bound as I
headed for Carlin’s Point, exploring and botanizing as I went.
Suddenly a gray tree frog began vocalizing repeatedly from the
nearby woods. Its call, at about the same pitch as that of a
spring peeper, slurred upward in a short delicate series of
staccato notes, very smooth and musical, ringing and far
reaching.
It is quite natural that so many people, upon hearing their
first singing gray tree frog, immediately wonder what bird is
making that strange but lovely call.
A few years ago Charlotte and I were leading one of our nature
classes and were enjoying the sights and sounds along the
boardwalk that crosses the vernal pond at Whitefish Dunes State
Park. There, placidly perched on the wooden structure ahead of
us, was a lone gray tree frog.
Fortunately the little amphibian was easy to capture and soon
we were admiring its wonderful color and warty skin. Gently
turning it onto its back revealed one of its seldom-observed
features, the strikingly brilliant yellow-orange under-surfaces
of the groin and hind legs that ordinarily are hidden from one’s
view when the frog is sitting.
Perhaps natural selection has "designed" this
two-inch-long wonderful singer to be nicely matched in many but
not all instances to its commonly used background, frequently
lichen-covered tree trunks and branches.
The ease of finding this well-camouflaged anuran is the exact
opposite of hearing its far-reaching song. In fact its species
name, versicolor, reflects perfectly the soft muted colors
of this small tree frog. Almost like magic this tree frog can
assume various shades of brown, gray or green, changing in as
little as an hour or two. Unlike what you might be tempted to
think, the color changes do not necessarily occur in colors that
harmonize with the frog’s surroundings.
Like its cousin, the spring pepper, it is very comfortably at
home in the trees. Hyla, the genus name of both of these
frogs, refers to wood or forest.
The skin of this creature is moderately moist and surprisingly
rough and warty, somewhat like the texture of the common toad.
The tips of its toes are extended into small discs, like
miniature suction cups, that facilitate clinging to very smooth
surfaces such as glass. One of its astonishing acrobatic feats
is its strength of jumping, almost as though it is flying. Just
one of its strong suction-cup toe pads coming into contact with,
for example, a branch, is enough to hold the animal firmly in
place and prevent it from falling.
It was our sharp-eyed viola-playing friend, Sally, who
recently discovered a gray tree frog comfortably perched on the
very top of the flower head of one of the zinnias growing along
our front sidewalk.
It was when I decided to move the creature to a
better-appearing zinnia, and one whose colors harmonized better
with the frog, that I learned how tightly it could cling to one’s
finger. In fact it was only with considerable effort that I
managed to literally pry or peel the frog from my skin. Now I
can clearly understand what enables these amazing creatures to
exist so effortlessly in the trees.
What great additions these bird-like-singing, insect-eating,
branch-hugging gray tree frogs are to the woods.
The gray tree frog sings like a bird,
eats many insects and is at home in the trees and on this zinnia blossom.
This column appeared in the Door County Advocate
on 08/23/2003.
© Copyright 2003 Roy Lukes. All rights reserved.
