I started reading about frogs in early February, when last winter’s strange warmth made me admit, at long last, that there would be no more snow in which to practice my mammal tracking. Now I turned my mind to an obsession with anurans — frogs and toads.
I wanted to be prepared for their early spring calls, so that I could seek them out on damp spring nights and hear them sing to the raindrops. For days, I let a tape of their vocalizations play over and over, and most of the calls evoked vague recollections of night-time ventures when I was younger.
None of the most basic — peepers and bullfrogs — could I pin to an exact location in my memories, but I knew that anurans had always sung where I could hear them.
My sister, a party in this strange obsession, listened patiently as I enthused over how familiar the calls were. “Of course they’re familiar,” she said. “You’ve been listening to nothing but that tape for weeks.”
She was right, but I knew that I would find amphibians in the spring and I checked out all of the field guides I could find in the library and began to read.
Amphibian literally means “both lives,” referring to these creatures’ strange life cycle beginning in water and then transforming into a land-crawling adult. These were the first vertebrates to make their way out of the water some 350 million years ago. The first amphibians evolved from fishes, denizens of the seas and forested
swamps which were beginning to dominate the landscape.
Later, some amphibians would evolve into reptiles that could leave their ocean heritage behind in the egg, but modern-day amphibians never quite made that final evolutionary leap. Even so, they must have been the hottest thing around when they first appeared, able to crawl up out of the ooze and breathe the air above.
They returned to the water to lay their eggs, which hatched into swimming larvae — tadpoles in our minds — which in turn eventually grew up and crawled out of the water again, re-creating that long ago journey of discovering life above the surface.
Although I had enjoyed catching frogs when I was younger, salamanders had been my amphibian of choice for many years due to their much-touted diversity in the southern Appalachians. But most of the salamanders weren’t due out of dormancy for a while yet, and my frog tape enticed me with promises of northern spring peepers and wood frogs calling in mid-February.
I made a list of species to be found in the eastern tip of the eastern panhandle of West Virginia (where I was located) and came up with 11 species: two toads, four tree frog allies, and five true frogs. Although learning sounds is a constant struggle for me, I decided that a goal of 11 species was well within my reach.
Rolling Ridge, where I was based, has perfect anuran habitat. Its rutted roads are spotted with vernal pools, which is herpetologist lingo for plain ol’ mud puddles. Although it seems a bit anti-intuitive at first, many anuran species prefer these transient puddle to the more permanent ponds.
Life for a frog, as for any other wild creature, is a contant balanacing act. Laying eggs in a vernal pool is dangerous — the pool may dry up before the tadpoles are old enough to transform into frogs, or the same vehicles that formed the ruts might drive back through and squish uncounted hundreds of young lives, or a hard freeze may kill an egg mass of early breeders like the wood frog.
But a pond is just as dangerous, though in different ways. Predators abound — from insects to fish to turtles to snakes and larger frogs — and a tadpole would be lucky to escape with its life. For many anurans, the chances of survival are better for an egg laid in a vernal pool, and so they test their luck against droughts and freezes and car tires, in much the same way that our migrating songbirds return to our northern hills to breed in order to escape the predators and diseases of their tropical wintering grounds.Puddle Hoppin’
In late February, I began noting puddles on a map as I wandered the property. Also low spots which would become puddles after the first spring rains. I watched the barometric pressure gauge on my wristwatch with an eagle-eye, noting any downturn that might signal oncoming rains. It was already a drought year and I fretted as I waited for raindrops under warm, cloudless skies. The skunk cabbages had bloomed in mid-December in this aseasonal year, but by the last week in February, I had to admit the frogs were late. I heard not a single peep.
On the evening of February 26, the first rainfall came. The storm didn’t amount to much — the rain gauge registered only a trace amount of moisture — but it was enough to send me out with poncho and flashlight to seek out the frogs. Only a single wood frog called from the pond near the house, but its crazy chuckle was enough to set my frog detectors afire. I sought out every puddle on the property, but the temperature had dropped to 48, which tends to cool frogs’ desire to call.
Two days later, I discovered that not all of the frogs had decided to wait for rain. Three vaguely spherical egg masses had been laid in a rut deep enough to hold water year-round. Each mass was about four inches long and must have contained dozens of clear, pea-sized eggs, each with a black embryo in the center. Wood frog eggs, I wondered?
A few days later, we had a downpour at last. Although the temperature stayed cool, the peepers began to call from the rushes in the shallow area of the pond. Unlike wood frogs, northern spring peepers require vegetation in their breeding grounds and our pond fit the bill. the first day they were hesitant; a few called, then they all paused for a minute or more before some brave soul resumed calling. When I came within 30 feet, they would stop calling and I gave up hopes of seeing a peeper, deciding instead to enjoy their chorus from a distance.
When I went out to check on the puddles in daylight two days after the rain, the frogs had gotten there ahead of me. Three puddles now had egg masses, and I found a mating pair of wood frogs under the thin ice in one nursery puddle, laying my mind to rest about who had laid the eggs. I cracked the ice with my fist and pulled the pair out, which was easy since their metabolism had slowed in the cold water. I didn’t really want to interrupt them, but it was important to be sure these were wood frogs.
To my surprise, the male showed no signs of loosening the stranglehold he had, with one foreleg around the female’s neck and the other just behind one of her front legs. So I turned them over as a pair, noting the black raccoon-like mask running from nose to behind the eye, and the strikingly pale upper lip. The female was quite a bit larger than the puny-looking male, and was more colorful, too, with mottling of brick-brown.
I lowered them back into the water and the female swam quickly away to bury herself into the mud on the pond bottom, leaving the male exposed above here except for a cap of mud on his head. He would cling to her for hours until she was ready to lay her eggs, and then he would release his sperm above them, fertilizing them as they were laid. The mass of eggs would expand as the water soaked into each clear capsule, growing from small enough to fit inside her 2 1/2-inch body to the 4-inch mass I’d seen earlier, and then larger still.
When March came around, I turned back on the frog tape. Although the peepers and the wood frogs were the first to begin breeding, every spring month would bring more species to join in the night-time vigil. Now I began to listen for the long, even trill of the American toad, the creaking calls of the upland chorus frog, and the snores of the northern leopard frogs. But the anurans didn’t know that I’d flipped the calendar, and for several cold nights everything was still.
On the ninth of March, a misty sprinkling began at mid-morning and by early afternoon, with the temperature hovering at 64 degrees, the peepers began to truly chorus. As soon as darkness fell, I crept over to the pond’s edge to listen and this time they continued to call as I tiptoed up to the rushes. I leaned closer and shone my flashlight across the vegetation, making my way toward one creature whose call was as loud and piercing as a smoke alarm.
After a minute’s careful searching, I found him perched on some dead leaves just at water level. He was about as long as the last joint in my thumb. His vocal sac was a huge balloon coming out of his throat, blown up to nearly as large as his body, and with every call it stretched a little larger until I thought it would pop. I had no doubt that the females could hear him, even if they were still hidden in their hibernation depressions under the leaves in the forest.
I left the cacophony behind me after awhile and skirted the pond’s edge as I headed toward the next puddle on my frog route. On the way, I nearly stepped on a toad. He had drawn himself erect as only a toad can and remained perfectly still. I crouched down by his side and peered closely at his warts. Although toads return to the water to breed, they are much more terrestrial than other anurans as adults. Their rough, warty skin may be useful in retaining moisture, that all-important molecule that chains many amphibians close to life-giving streams and ponds. The two huge warts where we would expect to see ears, though, serve another purpose: these are the paratoid glands, which secrete a milky poison that dissuades predators from eating them.
I walked for hours that night, from puddle to puddle, finding wood frogs and American toads in nearly every one. I was forced to keep my flashlight on at all times to avoid stepping on male toads making their way toward puddles, and I could hear the trill of the toads for long distances in every direction. Up a marshy cove, I heard a few stray spring peepers singing to the night. I counted frogs frantically, losing count once when a tree was pushed over by the wind and nearly fell right on top of me.
But the frogs were still there when I returned and I added another dozen hash marks to my field notebook, bringing the grand total up to 80 wood frogs and 16 American toads by the night’s end. I had checked maybe a dozen puddles, in which I would find nearly 100 new wood frog egg masses the next day.
There will be more frog nights in the months to come, and I plan to be out in as many of them as I can. As the spring progresses, more species will call, and I look forward to watching the eggs hatch into tadpoles and the tadpoles develop into frogs as spring turns into summer and summer into fall. I hope I can recapture the magic of that night I was out tripping over toads.
Anna Hess is a naturalist and illustrator in Harper’s Ferry, West Virginia.