Little Brown Bats

Posted on August 8, 2015 by Marcia Bonta | 2 Comments

little brown bat in a crack on the side of a house

The Guest House portico bat in 2007

Living, as we do, in an old country house, we often hear strange noises.

On an August evening, my husband Bruce and I sat in the living room reading. Shortly after 8:00 p.m., we heard unusual sounds coming from either the kitchen or sitting room.

We looked up at each other and then resumed reading. Both of us were engrossed in our books and didn’t feel like moving.

After all, many times we had investigated a noise and found nothing.

Then, there were more noises.

“I hope it’s not a bear,” I whispered to Bruce, remembering an attempted bear and cubs break-in back in June. “We’d better check it out.”

Because it was a wet night, it was already dark, and we couldn’t see a thing until Bruce switched on the sitting room lights. Then we ducked as a bat circled the room, narrowly missing the plates on our seven-foot-high plate rail.

Bruce opened the veranda door, but the bat continued its circling flight inside. As the minutes passed, I worried that mosquitoes, which had earlier driven us from the veranda, might get into the house.

But the bat was probably scooping up any that dared to enter and paid no attention to our feeble attempts to herd it out the door.

Location of the bat in the previous photo

Twice the bat barely missed the open door and once it landed for a few seconds on the wall, giving us a good look at its lustrous brown fur, but mostly it kept circling at plate rail height.

Bruce and I moved closer, he on one side of the door, I on the other, and I ducked reflexively every time the bat neared my head, even though I knew that its echolocation ability would keep it from hitting me.

Finally, it swooshed through the open door, and we breathed a sigh of relief. I was also elated that at least one little brown bat had escaped the white-nose syndrome (WNS), a fungus that has killed at least 95% of little brown bats throughout eastern North America since February 2006 when the disease was first discovered in a cave in Schoharie County, New York.

This cold-loving fungus Pseudogymnoascus destuctans only affects hibernating cave bats, which include the already Federally-Endangered Indiana bat, as well as the State-Threatened eastern small-footed bat, big brown bat, eastern long-eared bat, and tri-colored bat, but the little brown bat, also called little brown myotis, common bat, and cave bat, along with the eastern long-eared and tri-colored bats, is especially susceptible to the disease.

Dee Ann Reeder, A Bucknell University professor who has been studying bats in her bat vivarium even before the disease appeared, has been trying to understand how bats are affected and has been using little brown bats as her test subjects.

In a two-year captive study, she found WNS affected female little brown bats more than males and that bats kept in colder temperatures survived longer than those in warmer temperatures.

Little brown bats hibernating at Woodward Cave in central PA, February 2006

Reeder has worked closely with Greg Turner, PGC’s Endangered and Threatened Mammals Section Supervisor, to try to mitigate the disease, but this fuzzy white fungal growth around a bat’s muzzle, ears, and wing membranes thrives in winter hibernaculums—natural caves and old mines in Pennsylvania, such as the gated Hartman Limestone Mine at Canoe Creek State Park.

Back in 2008, when the PGC conducted its biannual count of bats at that mine, there were thousands of healthy, hibernating, mostly little brown bats. Three years later, they counted 38 total bats. And other hibernaculums throughout the state also contained few live bats.

Because bats cluster together in winter hibernaculums, the disease spreads easily from bat to bat. WNS causes them to rouse every few days instead of every few weeks as they used to do. The small size of little brown bats means they have less fat reserves to begin with so they quickly lose their fat reserves and starve.

They also lose more water through evaporation, and when they emerged, starved and dehydrated, for instance, from the Hartman Limestone Mine, they ate snow. In addition, little brown bats have suppressed immune systems during hibernation, which makes them more vulnerable to the fungus. Thus, once nicknamed the common bat, they are now rare.

Hibernating bats among the stalactites in Woodward Cave

Scientists say the best case scenario would be a full recovery of the bat population in 200 years! As of April 2015, the cave bats in 26 states and 5 Canadian provinces have been infected with WNS and still the disease rages westward at a frightening pace.

This is a huge wildlife disaster, certainly the worst in my lifetime, and all because some cavers, probably from Europe, where cave bats have evolved with the disease, brought the fungal spores over on their clothes.

Lately, there have been a few bright spots in this dismal picture. In 2014 the Hartman Limestone Mine cave bat count was 155, and this year 71 bats. Although the numbers are still low, according to Greg Turner, bats are coming into hibernation heavier, even the few juveniles, and they have fewer skin lesions on their wings. They also spread themselves out in hibernaculums. But all such changes may be due simply because there are few bats left to compete with for food and space.

Knowing all this, I welcomed our little brown bat visitor. One bat eats between 800,000 and 1 million insects a year including moths, wasps, gnats, midges, beetles, mayflies and especially mosquitoes, scooping up prey with its wings while flying or grabbing prey with its mouth.

Little brown bats have both day and night roosts during spring, summer and early fall. They like to roost near ponds, lakes, rivers or streams in buildings or trees, under rocks and woodpiles, and in caves. Females and their young occupy warm nursery roosts in natural hollows, buildings, such as old churches, at Canoe Creek State Park, for example, and attics.

A bat on the side of a concrete block outside our barn, 2007

They sleep almost 20 hours in a 24 hour cycle, saving their energy for when insect prey is most abundant—from dusk to two to three hours later and again for a shorter period before dawn. Flying at between 13 and 22 miles an hour, they hunt their prey using echolocation, a process in which they orient themselves by emitting high-frequency sounds and then interpreting the reflected sound waves.

They mate in autumn before hibernation, but fertilization occurs after the females emerge from hibernation the following spring. After a gestation period of 50 to 60 days, a single pup is born to a female in late May or early June.

Born with their eyes closed, the young hang in the nursery roost while their mothers hunt for food. The rest of the time, for two weeks, they cling to their mother’s nipple until they are two weeks old. At three weeks of age they learn to fly, and a week later they are adult-sized—between 3.1 and 3.7 inches with a wingspan of 8.6 to 10.5 inches.

Female little brown bats are larger than males, but all adults need to eat half their body weight each night, and new mothers more than their body weight. One study in New Hampshire of pregnant and nursing mothers found that they ate 7 insects per minute.

Before WNS, we could sit out on our unscreened veranda even after dark and rarely see or hear a mosquito. A few male little brown bats roosted in our barn and in openings under our roof and the guesthouse portico roof. We often watched them flying over our field and imagined them scooping up water from our stream.

Close-up of the little brown bat in the previous photo

Now the mosquitoes force us inside every evening. Farmers, who may not have realized how many harmful insects bats eat, will be forced to use more pesticides.

Little brown bats have few predators, although occasionally a snake, raccoon, skunk, or cat may enter a hibernaculum and kill a few. They’ve also been caught on barbed wire fences or in burdock bristles.

Before WNS, humans wiped out entire cave or attic nursery populations, but bat education by dedicated people such as Cal Butchkoski, a wildlife biologist for the PGC who spent countless hours at Canoe Creek State Park and other venues, presenting excellent programs on bats, and Environmental Educator Heidi Mullendore at the park who organized several successful Bat Festivals there, had begun to change peoples’ minds about bats. The PGC had also gated many vulnerable winter hibernaculums throughout the commonwealth.

Now it is illegal to kill even one bat of any species. With 6 million gone, “every bat we find is precious and needs to be conserved,” Dee Ann Reeder says.

All photos by Dave Bonta.

Pancake Flats

Posted on July 9, 2014 by Marcia Bonta | 1 Comment

Rhododendron along Green Springs Trail (photo: Stan Kotala)

On a cool, breezy day in late July, my husband Bruce and I decided to hike on Green Springs Trail. Following precise directions from our friend, Ruby Becker, we drove up the Allegheny Front, locally known as Wopsononock Mountain, on Wopsy Road, seven miles beyond the Penn State Altoona campus and parked in a State Game Lands #108 parking area. Since it was a seven-mile hike, and we are in our seventies, we planned only to hike the first portion, which our son, Dave, who had hiked the trail back in the spring with Juniata Valley Audubon Society members, said was the best part of the hike.

But we hadn’t counted on the seductive beauty of this trail. After a short walk on a gated road lined with a hedge of elderberry shrubs on one side and a bog on the other, we crossed a bridge over Tub Run and entered a mature second growth, mixed deciduous and coniferous forest. Most impressive were the healthy hemlock trees with not a sign of the hemlock woolly adelgid infestation. We followed a footpath through a tunnel of huge rhododendrons, many of which were still blooming. Black-throated green warblers sang “trees, trees, beautiful trees,” expressing our feelings for the impressive hemlocks.

painted trillium fruit along Green Springs Trail (photo: Bruce Bonta)

The ground was a boggy sponge on either side of the trail and mossy hummocks provided habitat for a wide diversity of spring wildflowers, their leaves evidence that if we returned next spring, we would see blooming painted trilliums, starflowers, Canada mayflowers, Indian cucumber-roots, and trailing arbutus, among others. Beds of partridgeberry and a potpourri of club moss species, as well as lady ferns and cinnamon ferns also favored the wet ground while clumps of white Indian pipes lit up the dark understory.

In addition to black-throated green warblers, occasionally we heard the singing of the brilliant red and black male scarlet tanagers, the persistent red-eyed vireos, and twice a black-throated blue warbler. But a succession of ethereal hermit thrushes provided a continuous choir of music that followed us throughout the five miles of the hike within the forest. Once a hermit thrush and hooded warbler sang at the same time in an unintentional duet.

As we penetrated deeper into the forest, Bruce, armed with a map and compass, kept asking me if I wanted to turn back. He knew that I hate to retrace my steps, and I knew that the complete trail was circular, which is my favorite kind of trail. Furthermore, unlike our hilly home grounds in the ridge-and-valley, this trail was almost flat in an area aptly named Pancake Flats and thus was much easier than I had expected. For that reason, I saw no reason to turn around.

A view of the stream from Green Springs Trail (photo: Stan Kotala)

Eventually, the trail became rocky, and below us we could hear the gurgle of Green Springs Run. On the woods’ floor were several huge flat rocks with rugs of moss and an understory of wood ferns. Dark-eyed juncos scolded us, and an eastern towhee exhorted us to “Drink your tea.” At last we had a view of Green Springs Run through the hemlocks and rhododendrons and descended to a bridge of large boulders that crossed the water.

We emerged out on to a grassy flat area that was, in reality, an overgrown road. As Bruce moved to examine the taller grasses on the opposite side of the road, he heard the unmistakable rattle of a timber rattlesnake. Although we stayed on the road edge and searched with our eyes to see the elusive reptile, we never did see the creature, but it rattled whenever we approached the underbrush. Finally, we took the hint and plunged back into the deep forest following Green Springs Run along the cleared footpath.

Beside the trail we spotted a pile of feathers—an indication that a predator had found its prey. A rock that had been wrenched out of the ground was evidence that a black bear had been searching for ants. We also paused to admire an enormous white pine beside the trail.

Tub Run from the trail (photo: Stan Kotala)

We stopped to picnic next to a picturesque small waterfall under a welcoming hemlock tree and then continued on through a forest with many young hemlocks and a nice stand of mountain laurel beneath the larger trees. Apparently, the leaf fungus that has killed many of our mountain laurel shrubs had not reached this game lands.

Cinnamon ferns and unfortunately also the invasive Japanese stiltgrass formed a portion of the understory. But I was delighted to find blooming dewdrops, also known by its genus name Dalibarda. Still another common name is star-violet because its leaves resemble those of violets, but its single, white, five-petaled flowers do not look like violets. In fact, this lover of bogs, peaty barrens and cool, mossy woods is a northern flower that grows at higher elevations on the Allegheny Front, according to Ann Fowler Rhoads and Timothy A. Block in their definitive book The Plants of Pennsylvania. In addition, I noticed the three-leaf, clover-like leaves of northern wood-sorrel, another five-petaled, white flower, that one with pink veins, which lives in the same habitat as dewdrops in Pennsylvania.

The last two miles of the trail were on the gated road. Even though the foot trail looked heavily used, we had seen no one on it, perhaps because we were there on a weekday. But on the road we did see a few people walking past us near the middle of the afternoon.

The trail was also remarkably trash-free except for an upright balloon caught on a sapling, wishing a happy birthday to a one-year-old, that had floated in from who knew where. Billed as “biodegradable” balloons, they still can be ingested by wildlife and last for years. We know this because often we find them on our mountain land above Tyrone, especially after their St. Patrick’s Day celebration when they release 3,000 balloons. We learned years ago that whatever pollution is released in the air eventually returns to earth and the same is true of balloons.

Dalibarda (dewdrops) in bloom along Green Srpings Trail (photo: Bruce Bonta)

Dalibarda (dewdrops) in bloom along Green Springs Trail (photo: Bruce Bonta)

The sunny, open road, in contrast to the dark forest, where we saw only a couple common wood nymph butterflies, was a haven for butterflies—great-spangled fritillaries, spicebush swallowtails, common sulphurs, red-spotted purples, and tiger swallowtails. Common and tall milkweed provided nectar for the butterflies, but sadly we saw no monarch butterflies, despite their milkweed food source.

It had been a terrible year for monarchs, and I had seen not a single one on our property despite abundant milkweed in our First and Far fields. Much later we learned that the population of migrating monarchs in their Mexican winter quarters had been reduced by 80%, an appallingly low number. Not only are their wintering trees being illegally logged in the Mexican mountains, but herbicides, such as glyphosate, used by industrial agriculture in our country, are killing off native milkweed species, the only plants on which the monarchs lay their eggs. So we applauded the managers of this state game lands for providing food and habitat for this rapidly declining butterfly.

The healthy forest and wetland also provide food and habitat for a wide range of birds and mammals. Best of all, from our standpoint, is that this enormous game land provides a refuge for those of us who appreciate wild Pennsylvania.

Giant Silkworm Moths

Posted on June 1, 2013 by Marcia Bonta | 11 Comments

mating promethea moths

On a warm day in late June, our caretaker couple Troy and Paula Scott was painting our barn. Around noon they spotted a female promethea moth clinging to her newly-vacated cocoon, which dangled from a spicebush branch. The Scotts called us to come and take a look at this gorgeous, velvety, giant silkworm moth. A rich, reddish brown, she had a bright eyespot on the upper edge of each forewing, and a white, kidney-shaped spot on both her forewings and hind wings.

She remained there, no doubt releasing pheromones like a siren’s call, and late in the afternoon a male answered her olfactory plume. With his dark maroon wings, he looked like a different species. But he had found the right mate because male promethea moths look very different form female prometheas. He was also smaller than the female. They mated immediately, both still clinging to the base of the cocoon, and by dusk he was gone.

He could have detected her pheromones as far away as 21 miles with his large, feathery antennae, but after mating his life was over. She, on the other hand, still had eggs to lay. We didn’t see her do that, but since promethea moths are also called “spicebush moths” she probably didn’t move from the shrub. She would have laid her eggs in short rows on the leaves of the host plant, which, in addition to spicebush, could have been the leaves of tulip trees, sassafras, wild black cherry, lilac or white ash. However, since the barn spicebush held six other promethea cocoons and the spicebush next to the springhouse several more, our spicebushes seem to be popular with prometheas.

The promethea silkworm moth Callosamia promethea was named for the Greek Titan who stole fire from the gods to give to mankind. The Audubon of giant silkworm moths, John Cody, in his beautiful book of paintings called Wings of Paradise: The Great Saturniid Moths, claimed that the promethea was aptly named because of her color, her fiery disposition, which he described as “easily excited,” and her emergence in the heat of a sunlit day. Most moths, even those in her subfamily, Saturniinae, emerge at night. That subfamily consists of 17 species in North America, five of which—polyphemus, luna, cecropia, tulip-tree, and promethea—live in the woodlands and backyards of Pennsylvania.

All of them are large, colorful, and attractively patterned. They have velvety wings and tufted legs attached to soft, furry bodies. As moths, they don’t eat or drink because of their undeveloped mouthparts, and they live on their caterpillar fat for the few days they are moths. Their job is to mate, lay eggs, and die. They are called silk moths because of the elaborate silken cocoons they spin.

While their life histories are similar, each species and even individual may vary in their choice of egg-laying sites and whether or not they produce one or two broods a year.

another view of the mating prometheas

Biologists have discovered that there is a biological clock in the caterpillar brain that can measure the relative amounts of daylight and darkness to an accuracy of 15 minutes per day. Depending on these measurements, the caterpillar will either spin its cocoon and then emerge as an adult or go into diapause, a pupal stage that reduces its metabolism and cell activity so it can winter over in its cocoon and emerge the following spring as an adult. For instance, if a polyphemus moth, in its 4^th instar, (one of the last larval stages between molts), detects 16 hours of daylight, it will pupate and emerge later as an adult, but if it detects only 12 hours of daylight, it will go into diapause. It continues to monitor photoperiod as a cocoon through a clear patch of pupal cuticle until its pupal brain responds to rising spring temperatures and triggers it to emerge as an adult.

Cecropia moths need a much longer time to develop than other giant silkworm moths and have only one emergence from late May through July. But in our area the luna, promethea, tulip-tree, and polyphemus often produce a partial double brood because offspring of a single female may have both fast-developing individuals that produce a second brood and slow-developing ones that pupate and enter diapause. In general though, late spring and early to mid-summer are the best times to find emerging adults.

giant silkworm moth cocoons in a tulip tree

Once a giant silkworm moth emerges, it crawls to a support or clings to its cocoon, as our promethea did, spreads its wings by pumping hemolymph ( a clear, green, liquid that fills a caterpillar in place of blood) into its wing veins and waits until those wings harden before flying. If it is disturbed or during its first flight, it discharges meconium, the waste it accumulated as a pupa. Usually, most species, especially the males, disperse in a brief flight at dusk.

Females release pheromones by protruding a special gland located at the tip of their abdomens. Those pheromones have specialized chemicals that identify her species to a searching male. Each species also synchronizes their mating activity during one or more specific 24-hour cycles.

Except for the tulip-tree silkworm moth (Callosamia anguilifera), which feeds only on tulip tree leaves and both sexes look like a brighter version of its close relative, the promethea female, the other giant silkworm moths are more catholic in their tastes. In fact, wild black cherry tree leaves and those of lilac shrubs are so popular with many giant silkworm moths world wide that they are called “universal donor” plants by scientists who use them to feed laboratory specimens.

Females find appropriate plants for egg-laying by smell. Polyphemus moths (Antheraea polyphemus), which have pinkish-cinnamon wings and a large eyespot on each wing, like ash, birch, grape, hickory, maple, pine and especially oak leaves. Apple green luna moths (Actias luna), also displaying an eyespot on each wing and have long, elegant, slightly twisted tails, prefer alder, beech, cherry, hazelnut, hickory, walnut, sumac, or willow leaves.

The gorgeous cecropias (Hyalophora cecropia) are the largest of our giant silkworm moths and have grayish brown wings highlighted in red. They are also the most cosmopolitan, even thriving in urban areas on ornamental shrubs and small trees, especially maple, wild cherry, plum, apple, birch, alder, dogwood and willow tree leaves. Also, while a female cecropia has only one partner, like the other giant silkworm moths, the cecropia male lives longer than the other male silkworm moth species and can have as many as three partners in his three nights of life.

Here on our mountain, we saw a cecropia clinging to a black walnut tree trunk near noon on July 4, 2011. Cecropias do emerge in mid-morning and stay quiet until the following morning at 3:30 a.m. when mating begins and continues until daybreak. The one we saw must have been a male because it was gone by 10:15 p.m., off in search of a female whose plume he could follow as far away as seven miles.

We seem to have two broods of lunas because I observed two mating at 9:00 a.m. on May 19, 2011 on a mountain laurel shrub, and two years in a row we saw a luna on a black walnut tree trunk on August 2, 2009 and August 6, 2012. They usually emerge in the morning, mate from 1:00 a.m. to 2:00 a.m., and then stay connected until the following evening unless they are disturbed.

luna moth and harvestman on a black walnut tree

I can’t remember when we last saw a polyphemus or tulip-tree moth. Most people today rarely see any of these giant silkworm moths. The artist, John Cody, who grew up in the Brooklyn borough of New York City back in the 1930s, fell in love with giant silkworm moths at the age of five when he found a cecropia. It smelled like peanut butter and didn’t move no matter how close he came to it.

“I had seen perfection,” he said of its fiery red body and splendid wings. But when his book was published in 1996, he mourned the mysterious disappearance of cecropias in the 1970s. Even though his neighborhood hadn’t changed that much, no one he questioned there remembered seeing any cecropias.

Not only the cecropias but all the giant silkworm moths have suffered a decline in the northeastern and Mid-Atlantic States, which some researchers have attributed to suburban sprawl, mercury light pollution, or the spraying of the bacterium Bt (Bacillus thuringiensis) for gypsy moth caterpillars. However, the most likely culprit appears to be the parasitoid Compsilura concinnata, a tachinid fly with a broad host range that was introduced into our country, along with nine other parasitoids, to kill gypsy moth caterpillars.

Cecropia moth (photo by Ethan Staats, Creative Commons BY-NC license)

While giant silkworm moths have numerous predators, including birds and bats, their most relentless and effective enemies are parasitoids, especially the families of wasps and flies that attack Lepidoptera (moths and butterflies) larvae. Some are generalists; others specialize in families or even genera. Usually they live inside the caterpillar and feed on its hemolymph and fatty tissues.

The female parasitoid finds her victims by smelling caterpillar frass (feces) and/or leaves they have damaged. Using her ovipositor, she lays one or more eggs in or on the caterpillar. When the parasitoid hatches, it burrows into the caterpillar. Some large ichneumonid wasps, attracted by the smell of freshly-spun cocoon silk, even attack cocoons. For example, one such wasp was observed attacking a cecropia cocoon by extending her ovipositor through a partially spun cocoon, laying her eggs, and stinging the caterpillar spinning the cocoon. But, in general, caterpillars in their last couple stages of molt suffer their heaviest losses from parasitoids.

Cecropia caterpillar (Michael Hodge, Creative Commons license)

All of the giant silkworm caterpillars are attacked by numerous parasitoids, although the cecropia, with a known 31 so far has the most. All five though are attacked by C.concinnata and Massachusetts researchers J.S. Elkinton and G.H. Boettner in their paper “The Effects of Compsilura concinnata, an Introduced Generalist Tachinid, on Non-Target Species in North America: A Cautionary Tale,” quoting the results of their own studies and others, show “that this species is probably having a severe impact on a number of our giant silk moths…”

Their study of cecropia caterpillars on understory wild black cherry trees found that none of the 500 cecropia larvae survived to the pupal stage. Most were killed by C. concinnata, a whopping 81%. They did a follow-up study on polyphemus caterpillars and found that the attack rate by C. concinnata was even higher. Another study by Virginia researchers on luna caterpillars recorded a 78% rate for C. concinnata.

Those and other studies led them to conclude “we believe C. concinnata is the most likely cause of the reported decline of giant silkmoths in the northeastern United States.” Once again, an ill-conceived, but well-intentioned introduction of a non-native has resulted in unintended consequences. To quote an old folksong, “When will we ever learn?”

Photos by Dave Bonta except where indicated. Click on any photo to view larger versions on Flickr.

Vernal Pond Adventures

Posted on April 1, 2013 by Marcia Bonta | 3 Comments

The largest of our vernal ponds in early April.

Once again I’m sitting beside our mountaintop vernal pond and wondering if this will be the year the wood frogs will make it out of the pond before the water disappears. A wood frog’s life span is about seven years, and for six years the pond has dried up before the wood frogs’ have fully developed. Some years their eggs are left high and dry; other years their tadpoles are.

A vernal pond is a temporary, fish-free wetland that fills in late winter or early spring and dries out by early summer in a good year. This pond is only several yards across and several yards long, depending on rainfall, and, unlike the tiny, 6-foot-wide pond at the base of First Field, I can’t get close enough to watch the courtship and mating of the frogs. I can hear their quacking calls, though, and I enjoy watching a wide variety of wild creatures that visit it even when I’m sitting quietly beside it, my back against an oak tree.

I find it incredibly peaceful to watch the pond as it reflects the trees in its still water. But this early March day a skim of ice over it glitters in the sunlight. Its surface has a medley of half circles and triangles artistically rendered by the ice-maker overnight.

On the thirteenth of March, as I near the vernal pond, circles appear in the water. I wonder if they can be disappearing wood frogs. I study the still, dark water and spot one small mass that I look at through my binoculars. A golden eye returns my gaze. I move closer and see a male wood frog stretched out in the water. Next to him is a stick with two clumps of wood frog eggs clinging to it. This unusually bold wood frog dives into the water but quickly resurfaces. Since I am still standing there, he sinks back under the water.

The vernal pond has already contracted, and I hope that the dark clouds rushing across the Allegheny Front will drop some rain on us and fill up the pond. But it doesn’t happen. Nevertheless, two days later, I find two wood frog egg masses in different areas. The gelatinous, fist-sized blobs contain several hundred eggs with black embryos.

By the 22^nd of March, I count four separate egg masses, but the vernal pond is still shrinking. If the rain comes soon enough, the eggs may survive. And come it does, raining hard from 1:00 a.m. until mid-morning on March 24, filling up the vernal pond again.

The vernal pond in mid-March.

It’s almost a month before I return to the pond. At the beginning of April, while hiking on Sapsucker Ridge with my sixteen-year-old granddaughter Eva, she steps on a branch and I trip over it, my left leg landing hard on a pointed rock. Nothing is broken or fractured the doctors tell me, but my leg and foot swell up and turn black and blue. I have, after all, injured my tibia, the bone just below my knee. After days of being veranda-bound and more days of slow, short walks, I finally make it back to a vernal pond seething with insect life, most notably water striders walking atop the water and looking for mosquitoes resting on the water just after they have emerged from their “wriggler” larval stage.

Various species of diving beetles also swim in the water on the hunt for invertebrate and vertebrate creatures, including the wood frog tadpoles. I have always marveled at how these insects find a vernal pond, especially this one, isolated on a mountaintop half a mile from the nearest stream and that one intermittent near its source. Apparently, they are able to fly to it from such water. But some species of diving beetles actually overwinter in the basin formed by a dried up vernal pond.

The wood frog eggs have long since disappeared from sight, colonized by the symbiotic algae Oophila amblystomatis, which turns them green. It’s been cold most of the month, delaying the hatching of the eggs. But near the pond I stop to admire the patch of spreading spring beauties, the only place they grow on our property. This is an open, mixed-oak forest close to our neighbor’s logging operation that took place several years ago. Not much has regenerated and the vernal pond is not as shaded as it used to be.

It’s now the fourth of May and torrid summer weather has returned. I practically stumble over a porcupine as I approach the vernal pond and send the creature scrambling up a large red oak tree. The vernal pond is a veritable tadpole soup—tadpoles by the dozens wherever I look, floating near the surface to warm themselves up now that the trees have leafed out and are shading the pond. They need the solar heat to develop quickly into frogs before the pond dries up. First they graze on the symbiotic algae still clinging to their gelatinous cradle, and then they feed on algae and leaf material on the pond’s bottom. They also may feed on each other, those that hatched first preying on the latecomers.

Three days of hard, cold rain follow, and once again the vernal pond is overflowing and seeping over into a series of wallow-sized pools. My pond-watching becomes an almost daily discipline as I sit and watch the tadpoles eating, swimming, and basking in patches of sunlight. In mid-May I hear clucking as a hen turkey circles behind me. Maybe she is hoping to catch some tadpoles for brunch.

Water striders

Often the tadpoles join in aggregations of ten on a submerged stick. Then there is a sudden flurry and they separate, but in a few seconds they gather together again, performing their own watery tadpole ballet. In addition to basking in the sun, perhaps they are finding refuge from predators in a crowd like flocks of birds do.

By the twentieth of May a few of the larger tadpoles are developing back legs. I sit close to the water and watch as the tadpoles continually surface to feed on the detritus floating on the water, then submerge, each tadpole swirling the water into a circle. I try counting the circles to figure out how many tadpoles still inhabit the pond, but the confusion of circles quickly confuses me. Instead, I settle back and enjoy the ambiance of the pond and surrounding woodland having long ago learned to tune out the occasional train whistle and the constant traffic noise on Interstate 99 at the base of the ridge.

A mourning dove sings without ceasing. Red-eyed vireos, eastern wood pewees and a scarlet tanager frequently add their songs to that of the doves. Water striders skate along the water. A common green darner dragonfly buzzes over the pond. Then an American crow flies in like a kamikaze fighter plane, veers when it sees me, and silently retreats.

There are more days of rain and again the pond overflows. The pond water is so dark that I can’t glimpse the tadpoles, but dozens of circles that gradually subside as I sit in front of the pond indicate their presence. Sitting beside the pond, a sudden nearby gunshot startles the tadpoles as much as it startles me. Not only do they have sharp eyes but sharp ears too.

Near the end of May, I’m serenaded by a robin and scolded by a hairy woodpecker while I sit beside the pond. I also see a dark-eyed junco, which should have been breeding farther north on the Allegheny Front or beyond by now. A mourning dove flies in to catch insects from the pond and goes off in a flurry when it realizes I am there. A black-and-white warbler sings. Chipmunks scold. Mosquitoes that probably have hatched in the pond circle me and force me to move on after I catch a glimpse of a few more tadpoles with back legs.

My vigil continues in June. By then, I wonder if those tadpoles will ever change into bandit-masked wood frogs. On June 8 many heads pop up from the water and stay up even though most tadpoles still have tails. Two male robins hold a song fest while a female chases all comers to the pond as her spotted youngster bathes. Later a tufted titmouse takes a bath. Chipmunks chase around the pond and one scampers up to me, pauses at my feet to look, and then continue its race with its rival. A pileated woodpecker pounds on a nearby tree trunk.

Wood frog in mating season (in the tiny, spring-fed pool at the bottom of First Field)

All the while a pleasant breeze blows, keeping biting insects away. The pond is slowly shrinking, but it is still a bathing and watering hole for birds and mammals alike.

The following day I spend another session at the vernal pond serenaded by the same two robins. Little mouths surface to catch detritus spread atop the pond, and once I see a tiny froglet hopping over a small section almost as if it could walk on water. Froglets are supposed to be between a half and 7/8^th of an inch when they metamorphose. Their watery life is ending and none too soon.

A chipmunk approaches me with much trepidation, and when I don’t move, it goes to the pond and drinks. Then it scampers off.

Suddenly, the robins begin high octane scolding as if, after half an hour, they finally notice me. On and on they scold, but at last they subside.

When I am too stiff to sit any longer, I get up and walk back to the field path. There I find an enormous pile of fresh bear scat that wasn’t there before. It looks as if the robins were scolding a bear.

A couple days later, as I’m sitting by the pond, I hear crashing in the woods that sounds like a bear. Sure enough, one approaches the pond, and I ponder my position. It’s obviously hoping for a drink and doesn’t see or scent me. At last I stand up, and the bear looks up, sees me, and flees.

The vernal pond continues to fill every time it rains, and slowly the froglets depart, although I don’t see them. But there are fewer circles in the water, less little heads surfacing, every time I visit. How wonderful that after so many springs when the pond dried up too soon, our aging population of wood frogs will finally get some newcomers. The young frogs will spread out, traveling up to several hundred meters in all directions, making new homes in the leaf litter, and preying on a variety of arthropods.

But even as the pond shrinks and the froglets leave, I still seek quiet time beside it. One day, late in June, I encounter an eastern box turtle, floating in a couple inches of water, its eyes closed. At first I think it is dead, but when I touch it, it opens its eyes. Later, I learn that eastern box turtles like to soak and feed in vernal ponds.

Wood frog found under a rock in Plummer’s Hollow Run in September

On another day, two doe wander past me and water at the pond while I sit a few feet away. Then they continue on their way. They never do detect my presence.

I can only wonder how many other wild lives are impacted by this small pond. Even though knowledgeable foresters will steer logging operations away from such places, most loggers either don’t know or don’t care about such refuges. Or they begin their logging operations in the fall when the ponds are dried up and they don’t recognize them for what they are.

My own life has been enriched by our vernal pond this water-full spring. Even after it is completely dried up, in broiling hot, droughty July, I wander back to sit under the oak shade. Where have all the wood frogs gone?

One day, on my daily walk, an adult wood frog hops across my path.

“There you are,” I say out loud as it hops quickly out of sight.

Marcia Bonta

naturalist writer

Category Archives: Insects and other invertebrates

Little Brown Bats

Pancake Flats

Giant Silkworm Moths

Vernal Pond Adventures

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