Ghost Bird
Barred Owl by lezzie5 on Flickr (Creative Commons BY-NC-ND license)
It’s a cold, crisp morning in early November. Robins call and sing in the sunlit treetops at the edge of First Field. As I head down our woodland road, first one and then a second common raven flies low and “bonks.”
Above Waterthrush Bench I hear the continual ticking of songbirds near or in a medium-sized hemlock tree across the stream. In the still sunless hollow, I look and look and still can’t see any little bird, yet the ticking continues.
Finally, I give up and am about to walk away, muttering about my aging eyes, when I notice what appears to be an odd-shaped piece of wood on a lower branch of the hemlock. Slowly, I raise my binoculars and peer at it. To my great delight and astonishment, a barred owl seems to be looking at me except that its eyes are closed. I speak to it and its eyes blink open. For long minutes we stare at each other. Then I move on, and the barred owl remains on its perch, seemingly unperturbed by the human who has interrupted its sleep.
Still marveling at its calm demeanor and superb camouflage, I wonder how many times I have not seen a barred owl in our forest. If not for the ticking birds, I would have continued on my walk, unaware that what I think of as the “ghost bird,” was nearby.
I remember our first year here back in 1971 when a barred owl sat in full view on a branch beside our road throughout the summer months. We didn’t realize then that the owl would be only a memory for years to come. We often saw or heard eastern screech-owls and great horned owls but never the “who cooks for you, who cooks for you’all” of barred owls. After all, great horned owls are major predators on the slightly smaller barred owls. So are raccoons, larger members of the weasel family, and large hawks, all of which live and hunt in our hollow.
Barred owl in flight by Curtis Ellis (CC BY-NC-ND)
Still, we do have ideal barred owl habitat — a mature mixed deciduous and coniferous forest on either side of a small stream along our hollow road. The barred owl’s favorite food items — small mammals and birds — are also plentiful, especially chipmunks, deer and white-footed mice, as well as birds up to and including ruffed grouse in size.
Knowing all this, I expected to see more barred owls in the hollow. Instead, my absolutely best sighting took place about 20 years ago in the ice-enshrouded woods of Sapsucker Ridge one January afternoon, well within the more than square mile of territory a barred owl pair needs to survive the winter. Two inch long icicles hung from every tree branch and vine that gray, cold, misty day.
This time an American crow was the messenger, cawing and flying up from the trees ahead. Scanning the area it had just vacated with my binoculars, I spotted a large, plump figure perched on a tree limb a hundred feet away. I thought it was a great horned owl because crows had often alerted me to them. Instead, I was surprised by a barred owl — a puffy vision decked out in white, gray, and brown feathers, its horizontal barring around its collared neck accounting for its common name.
It turned its head back and forth on its swivel neck, then bent and peered down at the ground, no doubt hoping to surprise a mouse. I knelt, one knee in the icy snow, and studied the owl for ten minutes, admiring its nearly rounded-off, soft-looking head framed with what looked like enormous fur muffs, and its dark brown eyes accentuated by large, oval facial disks.
At last it turned its back to me, and I could see some black mixed with brown on its stubby tail before it leaned out and slightly down and launched into silent flight, propelling itself out of my sight.
Sleepy barred owl by Signe Brewster (CC BY-NC)
Standing upright at 18 inches, a barred owl weighs a mere 1.5 pounds and its rounded wings stretch 40 inches. Among the owl species, only great horned owls are larger than barred owls in the eastern United States.
Once barred owls (Strix varia) resided east of the Great Plains from the boreal forest of Canada to southern Florida, but recently they have expanded into portions of western North America, including the Pacific Northwest where sometimes they displace and hybridize with the closely related and much rarer spotted owls (Strix occidentalis).
They are supposed to prefer large trees in old forests for nesting, and here in Pennsylvania barred owls do inhabit wooded ravines and “nest in highest densities in old-growth forests of the High Plateau,” according to Gerald McWilliams and Daniel Brauning in The Birds of Pennsylvania. But they are also found in forested swamps, wet, mature woodlands, and even in cities and farmlands. Although they are less abundant than great horned owls and eastern screech-owls, they breed in every Pennsylvania County except Philadelphia.
Barred owls need large trees with cavities for nesting but will use old hawk, crow or squirrel nests too. They will even nest in nest boxes on occasion, such as the barred owl that nested in a box in Loyalville, Luzerne County, McWilliams and Brauning report. Even though they sometimes reuse the same nest for as long as ten years, they have been known to alternate occupancy one year or several years with red-shouldered, red-tailed and Cooper’s hawks and great horned owls in so-called “partnership” nests.
Barred owls also like to inhabit a forest with an open understory because it makes hunting easier for them. In addition, the closed canopy of an old-growth forest provides more regulated temperatures as well as protection from excessive mobbing by small birds. But often they remain attached to an area even as it changes around them, for instance, even staying in a woods while it’s being logged.
Young barred owl yoga by Matthew Paulson (CC BY-NC-ND)
If there is enough food, both the larger female and the male of a pair will inhabit their 695-acre-or-more territory all year. They are presumed to be monogamous and even though they call throughout the year, they call more frequently prior to egg-laying in late winter and early spring. That’s when you are most likely to hear dueting between a pair lasting two minutes and consisting not only of their familiar hooting but “loud and prolonged outbursts of cackling, laughing, and whooping sounds delivered very rapidly and interspersed, as well as ending, with the familiar ‘ho-hoo-ah,’” Massachusetts ornithologist William Brewster once wrote, adding a reference to “a prolonged and cat-like scream.” It’s enough to frighten naïve campers into thinking a mountain lion is nearby.
Regarding their courtship rites, Edward Forbush, writing in Birds of Massachusetts and Other New England States, recounts how a pair of barred owls perched in low branches over his campfire and “nodded and bowed with half-spread wings, and wobbled and twisted their heads from side to side, meantime uttering the most weird and uncouth sounds imaginable.”
The female barred owl lays two to three white eggs as early as December in Florida and March and early April in Pennsylvania. She also incubates the eggs from 28 to 33 days while the male brings her food. After the eggs hatch, the female broods the altricial young for two weeks and the male delivers the food at the nest in a bill-to-bill exchange with the female. Then she tears up the food and feeds it to their nestlings. She also does a little hunting on her own, but after two weeks of brooding, she does a lot more hunting. Both parents then drop food into the nest and the nestlings are able to eat it by themselves.
When the nestlings are between four and five weeks old, they leave the nest but they can’t fly. They either perch on the nest rim or they climb trees or branches by using their beaks and talons, grasping the bark in their beaks and walking their feet up the trunk while flapping their wings. At ten weeks old, they can make short flights and gradually lengthen those flights.
Barred owl parent and fledgling by Minette Layne (CC BY-SA)
The fledglings stay together and near the nest site for awhile and the adults continue to feed them. That’s when Tom Kuehl, president of the Pennsylvania Society for Ornithology, first learned of a nesting pair near his Murrysville, Westmoreland County home. As he wrote in PSO Pileated, the excellent newsletter of the Society, “I walked out our side door at 6:00 a.m. [in late May]… as I made my way around the house, I started hearing loud hissing noises… I looked up and in spite of many leaves, I quickly found three fledgling Barred Owls… For the next two weeks we [his wife Janet and he] enjoyed the dawn and dusk hissing and antics of the fledgling Barred Owls. More active at dusk, they performed flights across the yard, tree to ground, then tree to tree as darkness approached.” The Kuehls never did see the parents, although Janet was scolded by an adult when she tried to walk on their woods’ trail.
Most documented young barred owls disperse a mile to 38 miles from their nest site, but one young barred owl that was banded in Nova Scotia in 1999 was recaptured in January 2000 960 miles away.
Barred owl in a beech tree (detail) by Michael Hodge (CC BY)
Unlike many bird species, Breeding Bird Surveys from 1966 to 1996 showed a slight increase in barred owl numbers. But that was 15 years ago. Since then the opening and fragmenting of forests has increased in Pennsylvania, providing habitat for the more aggressive great horned owls. In addition to too many roads that have fragmented our habitat for decades, we now must contend with industrial wind farms fragmenting our remaining intact mountaintops and natural gas well pads doing the same in our state forests and parks. Add to that the death of our state tree — the hemlock — from the hemlock wooly adelgids, which destroy the most common conifer in our mixed forest. All of these factors bode ill not only for barred owls but for all the creatures and plants that thrive in mixed coniferous/deciduous unfragmented forests.
Lives of Woodland Snails
Imagine having the time to watch the life of a woodland snail. That’s what happened to Elizabeth Tova Bailey when she was felled by a mysterious neurological illness that put her flat on her back. She could not move without pain, and so she was tended by a caregiver in a studio apartment.
Then, one day a friend brought her a pot of purple field violets that she had dug up in a New England forest. It also held a woodland snail. After finding the hungry snail had chewed square holes in her letters during nighttime forays out of the pot, she put withered flowers in a dish beneath it and watched from her bed as the snail crept down the side of the pot and ate the blossoms.
“I could hear it eating. The sound was of someone very small munching celery continuously,” she writes in her charming and informative little book The Sound of a Wild Snail Eating. Thus began her sedentary adventures with this intriguing creature.
It reminded me of my own encounter with a woodland snail many years ago when our three boys were children. On a hot, dry day in early August, I spotted one climbing a leaf. When I looked at it with my hand lens, it ignored me and kept moving instead of withdrawing into its shell as snails usually do.
Fascinated by what I thought was an unusually sociable snail, I plucked the leaf and carried it and the snail home to show our sons. When I put it down on the kitchen table, it quickly moved to the edge of the leaf and on to the table. Then I put my forefinger in front of it, and it climbed up on it. I could feel the suction from its pinpoint-sized mouth as it “tasted” or rasped my skin, a painless feeling similar to being licked by a cat. I also watched it excreting slime from a gland behind its mouth, which enabled it to glide smoothly over my finger.
Moving one inch every ten seconds, it circled my finger several times before moving to its tip and extending its upper pair of tentacles toward my second finger. It stretched the front part of its body across the gap and its head landed on my middle finger. At the same time, its shell dangled in the gap and its foot or tail remained on my forefinger. But it quickly pulled shell and foot on to my middle finger and performed the maneuver twice more to reach my little finger.
From tip to tip, its body measured two inches and its pair of larger tentacles with primitive eyes at its end was a half-inch long. Below them, near its mouth, were two small tentacles that are sensitive touch organs.
When I put it back on the leaf, it withdrew into its shell. Still, our son Dave persuaded me to let it stay until my husband Bruce returned from work and could photograph it. Bruce arrived two hours later, and I told him about my adventure.
As if on cue, the snail emerged suddenly from its shell and resumed its exploration of my fingers while Bruce took pictures. What a ham! Afterwards, I put it outside on a leaf and off it went.
Later, I did some research on woodland snails and learned that they usually estivate on hot, dry days by drawing into their shells and sealing themselves off with a mucus door called an epiphragm. That same mucus it had secreted on my fingers has a high acid content that allows it to dissolve the calcium carbonate the snail must ingest to keep its shell strong.
A woodland snail obtains calcium by eating decaying leaves and wood, fungi, algae on wood and rocks, sap, animal scats, carcasses, other snails, bones, antlers, and soil. They also absorb it through the soles of their feet. Calcium carbonate not only forms their shell structure, but also helps in “fluid regulation, cell wall function, muscle contraction, and egg laying,” according to an excellent web site on Pennsylvania land snails, written by Ken Hotopp, Principal of Appalachian Conservation Biology, and edited by Tim Pearce, head of the Carnegie Museum of Natural History’s Section of Mollusks.
Unfortunately, acid rain reduces forest soil calcium, which, in turn can reduce snail numbers by as much as 80%. Decaying sugar maple logs are particularly rich in calcium. So too are calcium-rich limestone outcrops. Maybe that’s why we don’t see as many woodland snails on our acidic mountain land as are in our limestone-rich valleys.
In captivity, a woodland snail eats lime and paper to obtain calcium, which brings me back to Bailey’s adventures with what she later discovered was a white-lipped forest snail (Neohelix albolabris), a denizen of humid woodlands from Georgia to Ontario and west to the Mississippi River.
“Despite its small size,” she writes, “the snail was a fearless and tireless explorer… With its mysterious, fluid movement, the snail was the quintessential tai chi master.”
Bailey’s caregiver found an empty rectangular glass aquarium and fashioned a terrarium for the snail with goldthread, partridgeberry, checkerberry, mosses, polypody ferns, a rotting birch log and a piece of bark festooned with multicolored lichens, all organic materials on which a snail feeds. Every week it also ate one slice of Portobello mushroom. A mussel shell held water.
Like my snail, Bailey’s snail “seemed to defy physics. It moved over the very tips of mosses without bending them, and it could travel straight up the stem of a fern and then continue upside down along the fern’s underside.” But, in reality, it is its incredibly adhesive mucus that allows such feats.
She also watched it grooming itself as it arched “its neck over the curved edge of its own shell and cleaned the rim carefully with its mouth…Its curiosity and grace pulled me further into its peaceful and solitary world,” she writes.
Snails are mollusks in the Class Gastropoda, meaning “stomach foot,” which refers to their method of locomotion. The word “snail” is Old English and comes from the German “schnecke,” a spiral-shaped yeast bun.
A radula or chitonous organ in its mouth is covered with tiny teeth that point inward so it can grasp its food. Its soft body has a lung, heart, and gastrointestinal system which is connected to its shell by a mantle that stores up to 1/12th of its weight in water. It breathes partly through its skin and partly through a breathing pore, a little hole on the right side below its head called a “pneumostome.” Next to it is an anal pore for excreting undigested food in the shape of a tiny, twisted rope.
A woodland snail has three senses — smell, taste and touch. Their rudimentary eyes can only distinguish light from dark, and it can’t hear at all. Its tentacles are smell and taste receptors and can be regrown if they are injured. If its shell is broken, its mantle, the membrane-like organ around the snail’s aperture or opening from whence the snail emerges, builds new shell material.
Nearly 1/3 of a snail’s daily energy goes into mucus production, which is filled with antioxidants and regenerative properties. It even has material useful in treating acne. Mostly important for maintaining a snail’s skin and allowing it to move, it also is used to deter predators. When attacked, it exudes copious amounts which confuse or even smother its enemies. Such enemies are legion — beetles and their larvae, flies, nematodes, ants, mites, spiders, millipedes, shrews, mice, amphibians, reptiles and birds, particularly ground foragers such as ruffed grouse, wild turkey, thrushes and blackbirds.
Even larger snails, such as the gray-foot lancetooth (Haplotrema concavum), a widespread Pennsylvania species, eat smaller snails.
One of the more interesting predator/prey relationships is that between land snails and Cychrine beetles, the latter evolving narrower heads to pull snails from their shells, while snails have evolved more obstructed apertures.
In winter, a woodland snail stops eating, makes a burrow with soil and leaves, and withdraws deep into its shell, its sealed opening facing upward. Its heart rate slows to a few beats a minute and its oxygen to 1/50th of its usual intake.
Land snails mate in late spring, early summer, or fall, depending on the weather. Because most Pennsylvania land snails are hermaphrodites, meaning they have male and female reproductive organs, each snail produces eggs and sperm. Some snails can fertilize themselves. That’s what Bailey’s snail did.
Some snail families, after circling each other and exchanging tentacle touches and before mating, shoot tiny darts of calcium carbonate into each other. Researchers believe these are reproductive hormones that increase paternity odds.
Then they embrace in a spiral direction and mate by exchanging sperm, which is often in spermatophore packages. The donor’s penis transfers it into the receiver’s vagina, which, in both cases, is an opening called the “atrium” on the right side of the snail’s head. Once inside, the spermatophore releases the sperm and sperm and eggs meet in a fertilization chamber.
Shortly thereafter, depending on the species, one to dozens of eggs is laid in a damp area. Bailey’s snail laid some on top of the ground and some buried in the soil.
“Under a microscope the translucent egg-envelopes present a beautiful appearance, being studded with glistening crystals of diamonds,” wrote Ernest Ingersoll “In a Snailery” back in 1881 and quoted by Bailey in her exhaustive study of woodland snail natural history.
Bailey may be the first person to have recorded observations of a snail tending its eggs. Her snail produced 118 offspring, losing none, as it would have in the wild, to predators.
Eventually, Bailey recovered and returned home, releasing not only her original snail but also its offspring.
Worldwide, 35,000 land snails have been named, but tens of thousands are still not identified. In Pennsylvania, malacologists have discovered 120 land snail species of both shelled animals and slugs, although very little is known about the life spans and movements of most species. But one study in Illinois of the broad-banded forestsnail (Allogonia profunda), a species also living in Pennsylvania, found that it moved back and forth between its winter hibernation spot and its home in pieces of log mold during its four-year life span.
All these small lives are virtually unknown to us. And, as Bailey and I have discovered, even individuals in a species can behave differently. I never could figure out why the woodland snail I found was out on such a hot, dry day.
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For more information: Consult the Carnegie Museum of Natural History’s website at http://www.carnegiemnh.org/mollusks/palandsnails/
Read Bailey’s book, but if you find it at the library, as I did, be forewarned that it has been classified as a memoir by librarians, instead of a natural history book. It has a several-page bibliography of books and articles about land snails, both recent and historical. Here’s the trailer from YouTube.
Marcia with golden eagle (photo by Todd Katzner)
Marcia Bonta is the author of nine books and over 300 magazine articles. The blog portion of this website includes her popular “Naturalist’s Eye” column from Pennsylvania Game News, reprinted here on the 1st of each month. Unlike typical blog entries, these columns are written months in advance, usually about things that happened during the previous year. Read more…
