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Tree Frogs Use Birdhouses Too

Dear Bird Folks,

This morning I noticed a strange bird looking out of the hole in my birdhouse. It appears to be a frog of some kind. I called Mass Audubon and Dennis Murley told me that it’s most likely a gray tree frog. Here’s a photo. What do you think?

– Janet, Eastham, MA


Come on, Janet,

The name of this column is Ask the Bird Folks. It is not Ask the Frog Folks (although, that does have a nicer ring to it). The only things I write about are birds. You know that. Don’t get me wrong. I don’t have anything against frogs, but who wants to read about them? There isn’t much to say about frogs except that they are slimy, make weird sounds and have a lot of trouble crossing the road at night. But what is really upsetting me is that you called Mass Audubon and talked to Dennis Murley before you came to me. Dennis Murley? Seriously? I know Dennis Murley and he can’t even figure out how to put on his own shoes, let alone answer questions. Okay, I’m only kidding. Dennis is a superb naturalist and knows way more about frogs – and even birds – than I ever will. (However, I wasn’t kidding about him and shoes. He has real issues there.) Nevertheless, I’m going to write about your tree frog. Even though your question has nothing to do with birds, your frog was looking out of a “birdhouse,” so technically, I have to answer it. You got lucky this time, Janet.

Gray tree frogs have been a bit of a nemesis of mine. About five years ago, another lady, who had a frog-ish thing looking out of her birdhouse, brought in a similar photo. At the time, I thought the creature was some kind of toad. That’s what it looked like to me. Last summer, Gary, our hard-working UPS driver, told me about frogs that were living in strange places in his yard. He not only had a frog in a birdhouse, but he had additional frogs living in the pipes of his kids’ swing set. Usually, I ignore everything Gary tells me (after all, he ignores me when I write “fragile” on my packages), but this frog/toad thing was starting to annoy me. Why are amphibians taking over birdhouses? Why do frogs look like toads? And why are frogs playing on swings? Not being a frogologist, I had to ask for help…from Dennis Murley. Here’s what I found out.

Gray tree frogs are rather odd creatures, even by amphibian standards. They are tiny things, smaller than a Fig Newton (the cookie all frogs are traditionally measured against). As their name implies, gray tree frogs spend much of their lives high off the ground, living in treetops, or in swing sets. They are nocturnal creatures, only becoming active after dark to feed on moths, crickets and assorted other buggy things. They move about the trees with the aid of special pads on their feet. These pads, along with a bit of sticky mucus, allow the frogs to cling to tree trunks and branches. When winter arrives the frogs climb down from the trees and bury themselves under rotting logs or in leaf litter. When the ground begins to freeze up the frogs go into deep hibernation. During this hibernation their heart stops, there is no breathing and their brain activity is almost nonexistent. (Reminds me of a guy my daughter once dated.)

When spring arrives the frogs somehow manage to come back to life. After a few weeks of constant feeding to regain their strength, they head to the nearest body of water to breed. But unlike most frogs, these frogs don’t want to be in the water any more than they have to. The male usually climbs onto an overhanging branch and begins to call. If he is lucky enough to attract a female, he hops off his branch and joins her in the water. After doing whatever he needs to do to make baby frogs, the male climbs back onto his branch, has a cigarette and goes back to calling.

The most interesting thing about these frogs is that sometimes their color is gray, sometimes it’s brown or even green, and sometimes it’s a combination of all three colors. How is that possible? Believe it or not, these frogs have the ability to change their color to match their background. Aquatic frogs are able to dive under water in order to escape danger, but there is no water to hide in at the top of a tree. So instead of diving, tree frogs simply hide by blending into the background. From time to time these color changes make the frogs look like toads. (At least that’s what they look like to me.)

After a hard night of hunting moths, the little frogs need to find a place to rest. During the day some frogs hide among the tree foliage, while others crawl into crevices and knotholes. If there aren’t any knotholes available, they will also use holes in man-made structures, including holes in barns, sheds, and yes, even swing sets and birdhouses. Who knew?

It’s cool that you have a gray tree frog living in your birdhouse, Janet. However, I’m not suggesting that everyone should run out and buy a birdhouse in hopes of a tree frog moving in. In spite of what you’ve just read, the odds of getting a frog to use a birdhouse are pretty slim. Although, they aren’t nearly as slim as getting a UPS driver to pay attention to the word “fragile” on a package. That’s never going to happen.