If you think that Gray Tree Frogs are gray frogs that live exclusively in trees, you’d be mostly correct. If you are one of those types who want to be right all the time, however, then you shouldn’t say such a thing. This statement isn’t incorrect in itself but it is incomplete. Because Gray Tree Frogs are often green and they spend the most important part of their lives in the water or in the ground, they defy simple description. Even their scientific name –Hyla versicolor- refers to the multi-colored nature of the beast. Not all Gray Tree frogs are even Gray Tree Frogs! (there is a genetically different, but visually identical, species called Cope’s Tree Frog). No, if you want to be right all the time you should avoid nature entirely or get used to qualifying your statements. I suggest the latter.
So, it is safe to say that all Gray Tree Frogs spend a great deal of time in trees and shrubs. They are all (note the definitive nature of this particular statement) equipped with marvelous toe pads which act like suction cups for climbing (see below). They are very adept at performing acrobatic feats thanks to their acrobatic feets and can jump from limb to limb or even climb glass. It is also safe to say that when you hear them calling during warm summer nights, you will hear that sound emanating from over your head. Here is where a qualifier needs to be inserted, because that same sound, when made on a warm spring night, is more apt to come from ground level – or, more appropriately, water level.
The distinctive trill of the Gray Tree Frog reminds this naturalist of the churling sounds of the raccoon. I don’t like to think about raccoons more than I have to, so let’s just say it sounds something like the churling notes of the red-bellied woodpecker. Or, if that doesn’t work for you, then just listen here and come up with your own description for goodness sake!
Tree Frogs come out of hibernation (in the ground, by the way) in the springtime and congregate in woodland ponds. There they commence calling in order to attract mates and lay eggs. In this regard they are like all other local frogs and toads. Although, unlike many other frogs and toads, they tend to call sporadically throughout the summer months as well. Their call is loud enough when blurted in close vicinity, but it doesn’t carry very well. I’m sure there are those who would argue with me on that last point but to those types I would suggest climbing a tree and staying there. Either way, it is generally truthful to say that Tree Frogs are heard far more frequently than they are seen.
I waited until the dog days of summer to bring up this topic because it took me that long to finally get my hands on one. I’ve heard them calling from the spring pond across from my house (first part of the recording) and from mid-summer tree tops (second part of the recording) but I never had one framed within my lens until one was brought to my attention earlier in the week. The individual portrayed in these accompanying shots are the same beast even though he looks different in each picture. This is the problem with Gray Tree Frogs – they are hue shifters.
It takes around a half hour for an individual to change color. They do so by controlling the pigment in their star-shaped skin cells. Though they can only go from green to gray and back again, they can also control the intensity of the dark splotch pattern found on the back. The sides appear to stay gray for the most part regardless of the chosen back color. Against natural settings, Gray Tree Frogs are masters of camouflage. Since the color choice is primarily intended for the daytime rest period (they are nocturnal) Gray Tree Frogs can pass the daylight hours in either color mode depending on background. In the photo below, this fellow was resting up against the chunk of bark and his pattern matched perfectly. The second photo is of the same frog at night, at which time he was in green mode (see here also).
Oddly enough, the reason this frog was caught in the first place was because it was attempting to blend into a pinkish gray block wall. For some reason our frog reasoned that bright green would work in order to blend into such a background. Needless to say it stood out like a sore thumb or shall we say like a tree frog on a block wall.