Sunday, June 22, 2014

Cope's Gray Treefrog

A duo of male Cope's gray treefrogs, Hyla chrysoscelis, sit in a rain barrel. They were doing far more than sitting, actually - they were making a heckuva racket.

I spent much of the weekend in and around Burr Oak State Park in Athens, Morgan, and Perry counties with John Howard and Diane Platco-Brooks. We were there to scout for next weekend's epic moth-fest, Mothapalooza, an event that is drawing 150 people from all around Ohio and points far beyond. We found lots of cool sites and scads of interesting critters. Mothapaloozians are in for a good time.

Friday evening was muggy and wet, following a series of showers. One of our stops featured an insanely loud collection of Cope's gray treefrogs, and I could not resist stalking some of the little amphibious blowhards and making a few images.

We have two species of treefrogs in these parts, and insofar as I know, they appear identical and are visually inseparable. Voice is the key to ID. They're easy to recognize as treefrogs, however. Both have a light patch immediately below the eye, mildly warty skin, and a blotchy lichenlike pattern. They're also hefty; noticeably larger than spring peepers or chorus frogs. CLICK HERE for photos of the other treefrog. Those photos also show the chameleonlike color shift that these frogs are capable of. The frogs in this post are all a nice shade of mossy brownish-green, but if they were to spend enough time on leafy green plant material, chances are they'd shift to a lime-green hue. When on dryer substrates such as oak bark, treefrogs can change to a pearl-gray color.

Cope's gray treefrogs are southerners, occurring roughly in the southern one-quarter of Ohio. The other species, gray treefrog, Hyla versicolor, is found throughout the state and overlaps the Cope's range. However, I don't think I've ever heard the two intermixed and singing in the same locale. We did hear H. versicolor on this trip, but not in close proximity to Cope's.

Close in on a Cope's gray treefrog eye, which is a rather amazingly ornate organ. You can see the reflection of my Canon's twin light flashes in the pupil. If you want to really see amphibians well, go out after dark. They tend to be far easier to approach, especially when in song.

Cope's gray treefrog (and the other one) are tinged with a beautiful shade of lemon-yellow around the bases of the legs. We can also see the powerful suction discs terminating each toe. Treefrogs are excellent climbers and spend much time in trees and shrubs.

Of course, the most conspicuous element of this photo is the enlarged throat sac, as the animal was caught in full trill. It was deafening. It is amazing just how loud such a small amphibian can be. At one point, we spied eight or nine males at once, and all of them were in full song. Apparently, the louder one's song the better. One of the frogs managed to get himself inside a small drainpipe, and was singing from within. That was really LOUD, as if the animal had been wired to a stack of Marshall amps. AC/DC would have been proud of the little fellow.

The song of the Cope's gray treefrog is a short nasal trill, which is distinctly unmusical, at least when heard from a foot away. When the animals are more distant, they sound rather pleasing. The song does carry for quite some distance, and most people notice it but probably not many make the connection with a small frog. As the sound typically comes from trees, it is sometimes assumed that a bird is responsible.


Click on the video to hear a pack of Cope's gray treefrogs singing at VERY close range.

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