Vol. 17 Issue 12, Winter 2012
by Liam McGranaghan
The weather forecast called for heavy rains and warming temperatures in the days ahead. I felt an excited chill along my spine—not just with the hope that the long winter might be ending, but also in anticipation of the “Big Night.” I hurriedly emailed my wife, Laura, and told her the forecast, and we hastily scheduled a date night for the following evening.
By morning, a red sunrise greeted the new day, and I could sense change in the air. The temperature had risen considerably during the night, and the air was thick with moisture. I could feel and smell rain about to arrive. All day I looked out the window. By mid-day the rain had begun to fall. I could barely contain myself, feeling like a foxhound just before a hunt. Within an hour of arriving home, the truck was packed, and we were ready for our date night. We had flashlights, rain coats, umbrellas, containers and, last but not least, cameras. Minutes later the windshield wipers were flapping, and we were headed for one of the hilly, forested sections of the county. Our mission involved cruising roads adjacent to low wooded areas—these were places where spring rains draining off the hillsides would fill depressions on the forest floor, creating deep puddles and pools, also called vernal ponds. Such spots would attract the special animals we were seeking.
“Pick it up!” I yelled out the window for the second time with a greater sense of urgency. In the distance I could see a pair of headlights growing brighter. “Now!” That was my final plea. Laura quickly picked up a 7-inch Spotted Salamander from the wet road and sprinted over to the wood edge, depositing it in nearby leaf litter. Seconds later, the car flashed by, the driver seemingly oblivious to Laura standing on the side of the road and to the small creatures also on the pavement. Did the driver of the car wonder what I was doing parked in the pouring rain? Perhaps. But one thing is certain. The driver did not realize he had narrowly missed killing a 20- to 25-year-old salamander compelled to cross the road by a powerful maternal need to create the next generation. This driver—no doubt like countless others—was lost in his thoughts or perhaps busy talking on a cell phone. He had no idea this warm rainy evening was a “Big Night.”
To a naturalist, the “Big Night,” which is actually a series of nights, is an extraordinary time of year. It’s a time when hundreds, sometimes thousands, of a few select species of amphibians, such as mole salamanders and wood frogs, emerge from their long cold slumber of hibernation and migrate downhill to natal vernal pools where they fulfill an eons-old instinct to reproduce. If the weather cooperates and the pools stay full, a new generation of their kind will hatch in water and eventually move to the terrestrial world. The timing of their awakening and migration is a true wonder of nature. A unique set of meteorological conditions—such as air and soil temperature, rainfall amounts, ambient light levels and perhaps other factors naturalists are not privy to and known only to these highly specialized amphibians—determine when the “Big Night” occurs.
Naturalists do know that warm late winter rains bring on a creature’s urge to reproduce, which is so strong that many of these amphibians will travel a quarter of a mile or more to get to vernal pools. Most face incredible odds in their journey to get there. Imagine a gravid female salamander or frog weighed down with the burden of hundreds of unfertilized eggs in her belly. Moving at little more than a snail’s pace, she will slowly work her way through the forest floor trying to reach the pool where she was born. Along the way she will encounter a gauntlet of obstacles imperiling her travels. Predators such as Barred Owls and Red-shouldered Hawks stalk from above, while raccoons and skunks may lurk behind every tree. The terrain itself is difficult to traverse; fallen logs, large rocks and crevices impede her progress. She may have to migrate in sub-freezing temperatures over snow and ice, yet she forges ahead. Males face the same challenges, but without the burden of eggs. They travel faster and navigate the course more readily; perhaps this is why more males than females are seen at the pools. This drama has played out for tens of thousands of years every spring on “Big Nights.” In spite of the overwhelming odds against them, amphibians have survived, and their species still grace our woodlands.
To witness and be part of this journey provides a wonderful occasion for a naturalist. Secretive mole salamanders—such as Jefferson and Spotted Salamanders, and Wood Frogs, known as “vernal pool obligates” because they require fish-free time in water to breed—can be readily observed as they go about their courtship and breeding. These amphibians are usually tucked away beneath the forest floor or hidden in the leaf litter and are rarely, if ever, encountered. Other species may be observed as well. They are not true “vernal pool obligates,” but nevertheless take advantage of the pools. This group includes Spring Peepers, Chorus Frogs and American Toads. Upon arriving at the pools, the frogs burst forth in a raucous chorus, inviting others to take part in their jubilation. Soon the duck-like clucking of hundreds of Wood Frogs and the piercing “peep, peep, peep” of countless Spring Peepers are joined by the long trills of toads, each species heralding in their new year. It is an astonishing experience to behold, and while it may at times be a bit deafening, it’s hard not to smile and even laugh while amid this celebratory cacophony.
Unfortunately over the years this spring symphony is becoming more muted and the amphibians less numerous. Fewer mole salamanders take part in the annual trek, and each year their numbers dwindle further. Pesticide and herbicides take their toll, while habitat destruction and wetland loss play an even larger role. Progress has its price. But there is still a phantom menace where woodlands are intact and vernal pools remain. It comes in the guise of a sinuous and sinister black ribbon cutting across the path of amphibian migration. This dark menace consists of the roads and highways people travel each day. Where better to build a road than on a flat valley floor where cost can be minimized? It is a cruel and unfortunate coincidence that this is the very same place where nature allows water to puddle and form life-giving pools to an amphibian. Roads are now almost everywhere and few places remain inaccessible by car. To a salamander or frog, a road is just another obstacle to cross on the journey to reproduce. The consequences for them are, of course, deadly. Evolutionary change comes slowly to animals and does not work in the timeframe of technological advances. Amphibians will never evolve to cross roads safely, and without human intervention, amphibians will die where roads cross their path.
Fortunately, there is good news. There is a growing number of dedicated groups of citizens committed to saving amphibians and their vernal pools. Locally, those at the Loudoun Wildlife Conservancy are strong advocates in protecting wetlands and sponsoring the Loudoun Amphibian Monitoring Program (LAMP), in which members keep track of area amphibian populations and assist at amphibian road crossings on warm, rainy nights. In a few states, citizen groups have petitioned highway divisions to install highway barriers. These barriers channel migrating amphibians to roadway underpasses and deliver amphibians safely to their breeding grounds. Nationally, Frog Watch USA and others have programs to protect migrating amphibians.
After that initial car flashed by on the rain slick road, I parked the truck and donned on my orange vest. My wife and I walked back and forth on the 200-yard section of the road where most of the frogs and salamanders seemed to be crossing. We worked quickly, moving frogs is pretty simple, as they quickly hop out of the way and off the road as people approach. An occasional toad, with a short-legged hop, sometimes needed encouragement with the soft touch of a shoe. We hurriedly picked and moved every salamander we came across, better to be safe than sorry and potentially lose one. After a couple of hours, the rain stopped and stars began to appear. The once-steady stream of vernal pool obligates slowed to a trickle. So we headed home, our date night with amphibians over. While we didn’t save them all— which was heart breaking—we saved many. A few days later, Laura and I returned during the daytime and were greeted by the joyous clucking of wood frogs emanating from the forest near the roadside. Upon entering the woods, the frogs went silent and sank into the pools’ leaf litter, but we knew they were there. We could see the salamanders made it, as evidenced by the dozens of translucent and opaque egg masses stuck to submerged sticks and branches in the vernal pools’ clear water. Life was regenerating, just as it always had. As it turned out, our date night was truly a “Big Night.”
How can you help? Become a Loudoun Wildlife Conservancy amphibian monitor. And, as always, drive cautiously, especially on a warm springtime evening—it could be a “Big Night.”