Have you ever gone frog-spotting? Come along with me in your imagination! Even better, give frog-spotting a try at your nearby frog pond. It is one of the fun things to do at the vernal pool over the next few weeks after salamander night.
I like to go frog-spotting soon after salamander night because there is quite a ruckus at my favorite vernal pool when it temporarily turns into Frog City. The ruckus I’m referring to is the loud “peeping” of the spring peepers and the “quacking” of the wood frogs.
I like to see the shining eyes of those dozens, maybe even hundreds, of ruckus-making frogs. Secondly, I like to watch as those wood frogs and spring peepers inflate and utilize their fantastic vocals sacs to raise their voices in that chorus of spring. Thirdly, (a little secret here) the frog pond comes alive at night! So, while I’m out there enjoying the frog eyeshine, I get to see a whole host of other vernal pool inhabitants—it’s like they are having a birthday party for spring!
To go frog-spotting, I use a headlamp, not a spotlight. I also take along a flashlight with a red taillight lens taped over the front. I also head out wearing my chore boots. The boots are for wading. The headlamp is to light up the frogs’ reflective eyes, and the red flashlight is to shine around in the water to see all the creatures inhabiting the pool without scaring them into hiding because of the bright white light of the headlamp.
A headlamp is the most effective way to see the frogs’ eyeshine. A regular flashlight also works, but it’s a bit trickier. The trick is to shine the flashlight from near your eyes—maybe even shine the flashlight from between your eyes.
When you see the frog eyeshine, maybe you’ll wonder, “What makes their eyes shine?” Well, creatures that can see really well in the dark, like dogs, deer, elk, and some amphibians, have special reflective material at the back of their eyes. It reflects the light that hits it back through their eyes’ photoreceptors for increased night vision. Interestingly, I’ve read that researchers have concluded that some frogs can even see color in the dark.
You can frog-spot at other places and other times of the year. Of course, you won’t see as many frogs, but will likely see other types of eyeshine from other species, such as bullfrogs.
Almost anytime you are at Frog City, day or night, the spring peepers are making a lot of noise. You will probably wonder, “How can they make so much noise?”
In order to understand how they do this, I think it helps to locate one that is calling and watch it. I took slo-mo video so I could study it happening. When a spring peeper decides to start calling, it partially inflates its large-for-its-size vocal sac into a big elastic bubble under its “throat.” It also fills its lungs with air, so much so that it looks like it is going to burst its belly. Then the frog begins calling by forcing the air out of its lungs, running it through the “voice box” to produce the “peeeeep” and into the elastic bubble of the vocal sac. This makes the bubble stretch really big until it looks like it will burst. Then, because the vocal sac is stretchy like a balloon and the peeper stops pushing the air out of its lungs, the air rushes back to refill the lungs, and on and on and on it loudly goes.
The elastic bubble vocal sac effectively recycles the air and saves the tiny frog much time and energy while it keeps up its tremendous noise-making. Another contribution their vocal sac makes to the sound production is that this big bubble turns their “peeeeep” into an omnidirectional sound. In other words, their “peeeeep” radiates in all directions and it seems to fill the area with sound. This “sound coming from everywhere” is one of the factors that makes spring peepers hard to pinpoint.
Perhaps the main reason spring peepers are hard to locate is they are so small—about an inch or less—and they are also camouflaged. Here’s another tip to help you spot the “often-heard-but-seldom-seen” spring peepers. On cooler nights they stay down close to water, and on warmer nights (the really, really loud nights) many of them climb up on vegetation to project their calls farther.
Wood frogs also make a ruckus at Frog City, although it’s a quieter ruckus than the spring peepers’. I like to watch the wood frogs making their chorus during the daylight.
Imagine that we headed out in broad daylight to visit the frog pond. As soon as we jumped out of our vehicle, we could hear a chorus of quacking sounds coming from the vernal pool in the woods. It sounded like a whole bunch of weird ducks had taken over the pond, but of course we knew we were actually hearing the wood frogs from Frog City.
As we approached the frog pond to see what all the ruckus was about, everything fell silent and still like the calm before the storm. We expected that they would see us and stop all their noisemaking, so we set up my pop-up tent blind and settled in to watch. Pretty soon the frogs resumed their “quacking” and splashing, which made rippling circles all over the pond.
I have learned to set up a good blind, because during my first try with a blind, I simply strung up a piece of camoflauge burlap for a blind by the water’s edge. That did not work. I reckon the frogs could see right through it, because they would come drifting over to look at me, but they wouldn’t make any sounds while they were anywhere close to my side of the pond.
Anyway, with a good blind and a little time, we got to watch wood frogs calling at a close enough range to see that they inflate their dual vocal sacs both at the same time. Theirs pop out at their sides a bit behind their eyes and front legs. It happens really fast.
I am fascinated with the ripples produced when wood frogs call while in the water (which they do frequently but not exclusively). I’ve often watched as the ripples radiate out from each frog like so many pebbles thrown into the water. I have concluded that those ripples are part of the wood frogs’ communication.
Now, I’ve mentioned Salamander Night a few times. In case you haven’t heard of that before, Salamander Night is that first warm night in the early spring when it rains and rains and the salamanders, wood frogs, and spring peepers come out of hibernation and all head to the vernal pools. For a few weeks after Salamander Night, there are many frogs to see and perhaps some of the huge yellow-spotted salamanders remaining at the vernal pool. Soon after Salamander Night, fist-size salamander egg masses appear. They are mostly clear but sometimes milky white and are usually fastened to twigs and sticks. Wood frog egg masses also show up. They are large semi-loose jelly masses that have a bluish-gray tinge. The wood frogs often group many egg masses in certain areas of the pool. When you see them, you will be amazed at so many eggs!
There are also a whole host of other vernal pool inhabitants, my favorite being the fairy shrimp. The first time I ever saw a fairy shrimp, I had waded out into my favorite vernal pool and leaned over a log to peer into the water. There peering back at me with its beady, mesmerizing red eyes was a fairy shrimp. I was hooked, and I think I’ve gone back every spring since to watch the fairy shrimp. (As I write this, already tiny shrimp have hatched in my vernal pool. I first saw tiny ones December 30! Brrr!)
I also like to watch the water striders, mayfly nymphs, case-bearing caddisfly larvae, dragonfly nymphs, hydras, diving beetles, mites, ostracods, and midges, to name a few.
I suppose you are thinking, “Where can I go to frog-spot?” How about near your school? I can think of ….hmmmm…3…4…5 schools that have a vernal pool very close by. Good chance yours has one nearby. Your teacher might even enjoy taking your class out to see the frogs (more likely that than have the frogs come to school).
Maybe there’s a frog pond near your house. Can you hear the spring peepers while you are driving down your street or sitting in your living room like I can? Come to think of it, at my house, in the spring, there’s often a pool of water that fills up right in our brushy fencerow at the back of our little half acre. I wonder what I could spot there? I guess I never looked. Can you imagine that?
These things we’ve been talking about would have been fun for me to know fifty years ago when I lived right beside Frog City. You see, back in those days, I didn’t know my swamp/frog pond had eyes at night, nor did I know how fascinating it would’ve been to watch the wood frogs’ and spring peepers’ vocal sacs in action while they chorused at the frog pond.
So, I recommend that you take any opportunity to go visit your Frog City for spring’s birthday party to peer into the eyes of a fairy shrimp, watch wood frogs blasting ripples across the pond with their dual airbags, and also watch spring peepers turn themselves into omnidirectional speakers by inflating their elastic, energy-saving, oversized vocal sacs. Isn’t it fantastic that there is such a thing as frog-spotting at Frog City every early spring?