The Mystery of Night

Last September fall songbird migration was well underway. Almost every day I encountered a migrant in our yard, our meadow, or our forest. Many of the birds are not as colorful as the males are in spring and there are huge numbers of immature warblers that wear the drab coats of females such as the warbler I spotted as I walked up our driveway. It was foraging in a small black walnut sapling behind an old apple tree and paused long enough for me to note its grayish back and head, faint wingbars, yellow throat, breast and belly with faint streaking on its neck and breast. After studying Roger Tory Peterson’s two pages of fall warblers in his Field Guide to Birds of Eastern and Central America, I decided that the bird was an immature female prairie warbler.

An immature female prairie warbler (Photo by Linda Tanner on Flickr, Creative Commons license)

An immature female prairie warbler (Photo by Linda Tanner on Flickr, Creative Commons license)

Meanwhile, our birder son, Mark, was out every morning at dawn hiking eight miles up and down our property, recording bird species and numbers on his phone, the same as he had done during spring migration when he had found 101 species one mid-May day.

In both spring and fall, the migrant birds come into our property to eat and rest for the day because most songbird species—sparrows, warblers, flycatchers, thrushes, orioles, and cuckoos—migrate at night when they are safer from predators such as day-flying raptors, and it is also quieter.

Migrant birds use the Earth’s magnetic field to help them migrate, and recently researchers discovered how they see in the dark. A protein called cryptochrome, which is sensitive to blue light, allows them to do this because of an unusual cryptochrome eye protein birds have called CRY4.

So many birds migrate each fall that they can be detected by Doppler radar. And they are especially abundant when low weather systems are followed by highs that bring north winds.

Before they leave their breeding grounds they gorge on foods filled with carbohydrates and lipids like berries and other fruits and store them as fat. For instance, ruby-throated hummingbirds double their weight in four days before they embark on a 2,000 mile migration to Mexico and Central America. And here in Pennsylvania most ruby-throated hummingbirds are on their way as early as mid-August or early September.

A Swainson’s thrush (Photo by Mark Bonta taken in Plummer’s Hollow)

A Swainson’s thrush (Photo by Mark Bonta taken in Plummer’s Hollow)

Migratory birds sleep less, but they do sleep while flying. Swainson’s thrushes sleep for nine seconds on one side of their brain and then switch to the other side for nine seconds, keeping themselves half- awake to avoid predators or mid-air collisions with other migrating birds, researchers discovered.

In addition, migratory birds give short calls as they migrate at night, probably also to avoid colliding with other birds during massive migratory flights as well as for echolocation. Most of those calls sound nothing like their daytime calls and songs.

Back on September 14, 1896, Orin Lobby sat on a hill near Madison, Wisconsin and counted 3600 calls from night-flying birds during five hours of listening. His was the first known attempt by anyone to do this. There were only two other such studies in the next 50 years—one by Paul Howes in 1914 and the other by Stanley Ball (1952)—and both documented the night time call of thrushes, which are more distinctive than other songbird calls. Ball’s work was also the first to use such calls to time the migration of a region’s species.

The first audio recordings made of nocturnal flight calls (NFCs) used reel-to-reel tape recorders to automatically record 10-minutes out of every hour all night so recorders could sleep and later listen for bird calls on the recorders.

Then Bill Evans, in the 1980s, used commercial hi-fi video cassette recorders to record 8 to 10 hours of NFCs a night. In 1994, he joined the Cornell Lab’s Bioacoustics Research Program (BRP) working under Dr. Chris Clark to help develop computer-based automatic NFC detectors and BRP programmer Harold Mills wrote the first working NFC detector which could detect short, high-pitched flight calls of warblers and sparrows.

A wood thrush on our property (Photo by Mark Bonta)

A wood thrush on our property (Photo by Mark Bonta)

But Evans wanted to encourage citizen scientists to participate in NFC monitoring so he founded a nonprofit he called OldBird for NFC monitoring. Then he contracted a former BRP programmer, Steve Mitchell, to develop advanced software to be used on home computers. They began with dickcissel and thrush detection, but today anyone interested in listening to and recording the calls of NFCs on their home computer can purchase their own Autonomous Recording Unit and set it up.

That’s what our son, Mark, did last fall. On a pole near our barn, he attached an OldBird, 21c microphone enclosed in a large white bucket pointed skyward and ran a cable from the microphone into the barn where he had his laptop computer equipped with software to analyze bird calls.

The bucket, he explained, helped the microphone pick up calls as high as approximately 1,950 feet in the sky and within 975 feet of the microphone.

Flight Calls of Migratory Birds CD

Flight Calls of Migratory Birds CD

There is no field guide to NFCs, but there are sources online that are mostly based on Evans’s and O’Brien’s CD-Rom “Flight Calls of Migratory Birds: Eastern North America.” Mark showed me pages of NFC spectrograms and also had me listen to the short “zeeps” of several of these birds. The length of each call (in milliseconds) was at the bottom of the spectrograms and the sound—from 0 to 12 Kilohertz—on its left side. Near zero it was mostly black from insect noise, and Mark found that the din from katydids until a good freeze in mid-October made it almost impossible to hear the bird calls in September. So he did most of his recording from October 14 until November 22.

In all, he, with the help of fellow NFC experts and enthusiasts, identified 47 species. Some were easy, such as American robins that have the same call they use in the daytime, and others have distinctive spectrographs such as that of American redstarts which I identified immediately. The sparrows and warblers are all in the high kilohertz (six to 10 range) and nine warbler species have almost identical “zeep” calls lasting 60 milliseconds, while another nine warbler species with “up” calls last 30 to 50 milliseconds. But only two warbler species—northern parula and pine warblers—have the “single down sweep” calls at 50 milliseconds.

The sparrows are mostly two to a category, but Mark was able to distinguish most species. Still, even the experts are still working on 10% to 20% of bird species’ calls that can’t be identified. And he had his own mystery bird at 11:37 on November 12. No one, not even Bill Evans, is able to identify it so far.

Snow bunting flight call, detected during the early morning hours of November 13, 2020. Picked up loud and clear on a cold, insect-less night. Pitch descending from six to two kilohertz over 250 milliseconds (Image by Mark Bonta)

Snow bunting flight call, detected during the early morning hours of November 13, 2020. Picked up loud and clear on a cold, insect-less night. Pitch descending from six to two kilohertz over 250 milliseconds (Image by Mark Bonta)

On the other hand, the following night Mark heard the clear call of a snow bunting, a species we have never seen on our property. Another was that of a horned lark with the same call as we have heard down in Sinking Valley where they nest and even winter. He also recorded many savannah sparrows even though again we have never had one here.

As expected, the thrush calls were easy to distinguish and he heard gray-cheeked and Swainson’s thrushes, both of which I encountered on my walks. On September 19 a gray-cheeked thrush was foraging in the undergrowth beside Laurel Ridge Trail. A grayish, plump thrush, it has one of the longest migration routes—from the edge of the tundra to Brazil—of the thrush species and is the first thrush species to migrate, passing through Pennsylvania as early as the last week in August, although their primary time is from the second week in September to the first week in October.

The Swainson’s thrush I observed on October 4 in the underbrush beside our hollow access road. It breeds across Canada and Alaska and in the northern United States and migrates to Central and South America.

Wood thrushes and hermit thrushes both nest in Pennsylvania and wood thrushes, which are headed to Mexico and Central America for the winter, are mostly gone here by the first week in October, but hermit thrushes, the only thrush species to winter in the United States, including in Pennsylvania mostly in the southeastern part of the state, are the last to leave in mid-October to early November. Mark counted sometimes dozens of them a night.

As David Brown from Lycoming County writes on his excellent website about NFCs, [hearing] “the descent of thrushes in the pre-dawn hours of a fall is hard to beat…”

Greater yellowlegs flight call detected twice in early November 2020. Series of five notes around three kilohertz, lasting 800 milliseconds total (Image by Mark Bonta)

Greater yellowlegs flight call detected twice in early November 2020. Series of five notes around three kilohertz, lasting 800 milliseconds total (Image by Mark Bonta)

Flocks of geese, swans, and shorebirds also migrate at night and Mark recorded “tons of tundra swans,” and one night a greater yellowlegs call, a month later than any have been reported migrating. It is for such discoveries that Mark especially enjoys analyzing NFCs.

But he also likes hearing mammals moving about such as deer startling a bird or coyotes howling in the distance, what he calls the “mystery of night.”

Disappearing Bullbats

Years ago I used to hear the nasal “peents” of bullbats, also known as common nighthawks, as they flew over First Field at dusk on summer evenings.

A common nighthawk flying (Photo by Kenneth Cole Schneider on Flickr, Creative Commons license)

A common nighthawk flying (Photo by Kenneth Cole Schneider on Flickr, Creative Commons license)

During the 1970s, 80s, and 90s, we heard or saw a few most years, and back in July 1987, four nighthawks appeared every evening, “peenting” and swooping low in the company of a couple barn swallows and bats.

My husband Bruce and I also remember when he spotted four nighthawks over First Field on June 28, 1991, sifting the air for insects. We even noted the notched tails, white wingbars and throats of these gray-brown, big-eyed, wide-mouthed birds.

Throughout the 1990s, we continued to hear or see one to three common nighthawks most years, but in this century the only records we have of them are of one calling at 5:30 am on May 22, 2007, when our son Dave and I were conducting an Important Bird Areas Count on our property and on June 8, 2020, when our son Mark heard a nighthawk “peenting” in early morning along with calling whip-poor-wills.

A member of the nightjar family and closely related to whip-poor-wills, the name “nighthawk” was poorly chosen because these birds are not hawks and they hunt at dawn and dusk, not at night. Their other name—“bullbat”—refers both to the booming sound their wings make during their courtship flights and their erratic, bat-like flying.

Even the “common” in their name has become “uncommon” throughout their continent-wide, breeding range in North America, especially in northeastern United States and Canada. According to the North American Breeding Bird Survey, from 1966-2014, common nighthawks declined 61% throughout North America and the 2014 State of Birds Report labels them a “Common Bird in Steep Decline.”

A common nighthawk on the ground (Photo by Kenneth Cole Schneider on Flickr, Creative Commons license)

A common nighthawk on the ground (Photo by Kenneth Cole Schneider on Flickr, Creative Commons license)

In Pennsylvania, between our first atlasing (1983-89) and second atlasing (2004-2009) of breeding birds, Greg Grove, who wrote the common nighthawk account in The Second Atlas of Breeding Birds in Pennsylvania, pointed out in an email to me that “of all species with significant populations, nighthawks had the greatest decline in block detections from atlas one to atlas two,” — the number of blocks dropping 71% with only four confirmed records of nests containing eggs or young. For this reason the common nighthawk is now considered “Near Threatened” by the Ornithological Technical Committee of the Pennsylvania Biological Survey and a Pennsylvania Species of Greatest Conservation Need in the Pennsylvania Wildlife Action Plan.

Douglas A. Gross, in a 2013 article he wrote for the American Birding Association “Decline of the Bullbat,” recalled watching several nighthawks over his yard in Bloomsburg on summer evenings when he was a youngster in the 1960s. He believed they nested on the flat roofs of mills and other flat roofs in the town. However, he returned to his old neighborhood several times during the second atlasing period, and he didn’t see or hear a single nighthawk.

“They’re gone,” he wrote. “The community is poorer for it.”

Researchers hypothesize several reasons for their decline including lower numbers of flying insects because of pesticides and habitat loss such as open woods in rural areas and flat gravel roofs in urban localities.

A common nighthawk nest (Photo by Kenneth Cole Schneider on Flickr, Creative Commons license)

A common nighthawk nest (Photo by Kenneth Cole Schneider on Flickr, Creative Commons license)

Throughout North America, nighthawks use a number of habitats, but all are open and flat enough to hold the two white to pale gray speckled eggs the females lay on the ground, from rock outcrops to woodland clearings.

But in many places nighthawks became dependent on flat, gravel roofs, and when they were replaced by rubberized roofs, nighthawk eggs were no longer camouflaged, they rolled easily, and the rubber was hotter than gravel in the sun which may have been damaging to the eggs and later the chicks.

Daniel W. Brauning, in the first Atlas of Breeding Birds in Pennsylvania, wrote that common nighthawks were “almost totally restricted to manmade structures [for nesting] in Pennsylvania,” a practice that went as far back as 1869 when W.P. Turnbull mentioned nighthawks nesting on flat gravel roofs in Philadelphia.

Still, Grove wrote in his account, that one nesting site was on a former surface mine area in northern Clinton County and another in Carbon County on a newly-grassed area that had been denuded by industrial pollution. Other suspected nesting sites were found on former surface mines in Centre and Clearfield counties and in the coalfields in Schuylkill, Lackawanna, and Luzerne counties.

Nighthawk courtship flight, illustrated by Alexander Wilson in 1829

Nighthawk courtship flight, illustrated by Alexander Wilson in 1829

Because of a long migration back from Brazil, where most common nighthawks winter, they don’t arrive in Pennsylvania until May. The male performs courtship flights in which he flies down to within a few yards of a female and then turns sharply upward. His vibrating feathers produce a booming (or bulling) sound. Then the male lands beside her, spreads his tail, and sways back and forth, displaying his swollen throat and large white neck patch, while he emits guttural croaking notes through his closed beak. He also flies over the female repeatedly and “peents.” Eventually, they mate.

But he continues these flights and displays throughout the time his mate selects the nest site, lays her eggs and incubates them 16 to 20 days, usually in late May or early June in Pennsylvania. Once his offspring hatch, he starts feeding them regurgitated insects at dusk and dawn while the female continues brooding them for 15 days, although as the young mature she also hunts food for them.

Nighthawks use their wide-open mouths to capture as many as 50 species of insects on the wing including what seem to be their favorite–queen flying ants– as well as a many kinds of beetles, true bugs, flies, caddisflies, crickets, and moths. One nighthawk stomach examined by researchers contained 2,175 ants and another 500 mosquitoes.

Common nighthawk young in their nest (Photo by Clinton & Charles Roberts on Flickr, Creative Commons license)

Common nighthawk young in their nest (Photo by Clinton & Charles Roberts on Flickr, Creative Commons license)

After they hatch, nestling nighthawks can hold their heads up and open their eyes, and they are covered with soft down. For those reasons, they are considered semiprecocial or partly helpless instead of totally like songbird nestlings. By their second day they respond to the female’s call and move around. Most of their feathers have developed at 16 days when they hop up and down and they begin flying at 18 days. At 25 days of age, they can feed themselves while flying and they leave the care of their parents at 30 days old.

By the third week of August, common nighthawks begin their migration south and birders sometimes count nighthawks flying overhead in open areas an hour or two before sunset. Back in 1999 Greg Grove counted 270 common nighthawks flying over Lake Perez in Huntingdon County and in 2006 100 foraging over fields near McAlevy’s Fort, also in Huntingdon County.

Sometimes more formal Common Nighthawk Watches are held by organizations, for instance, the West Chester Bird Club hosts a series of nighthawk watches during the last week in August and into early September at Bucktoe Creek Preserve in Kennett Square.

Common nighthawks migrate throughout the day in large flocks and most were thought to go by way of Mexico and Central America and then on down through South America to Brazil.

But a new study, published in Ecography: A Journal of Space and Time in Ecology, used GPS data and transmitters to track common nighthawks. The study was led by researchers from the Smithsonian Migratory Bird Center (SMBC), the University of Alberta, and Environment and Climate Change Canada, and tracked 52 individual nighthawks from 12 breeding populations across Canada including Quebec, New Brunswick and Ontario in eastern North America and in South Dakota, Oregon, Arizona and Texas in the United States. They found that nighthawks from throughout the continent flew east or west to congregate in the Midwestern United States along the Mississippi flyway. From there they mixed together and took a common migration route south across the Gulf of Mexico to Colombia and down through the northern Andes, to reach their wintering grounds, mostly in Brazil.

As part of the Smithsonian’s Migratory Connectivity Project, the researchers plan to concentrate on the times and places of where common nighthawks are during breeding, fall migration in North America and before they cross the Gulf of Mexico during spring migration and hope by their studies to find out why nighthawks are declining. But as Elly Knight, lead author of the study and doctoral student at the Department of Biological Sciences at the University of Alberta, said in an article published by the Smithsonian MBC, “figuring out what causes these declines can be difficult and complicated for migratory species like the nighthawk because they occupy so many different places during the year.”

In the meantime, some conservationists are trying to entice breeding common nighthawks to nest on flat, rubberized roofs by placing gravel corners on them with the permission of building owners and by clearing patches of forest for open nesting sites. But pesticide use must also decline so that the aerial insects they depend on can once again provide food for them and the other birds and bats that also need flying insects to survive.

 

Our Fiftieth Anniversary

Fifty years have passed since we first saw our mountaintop home on the Fourth of July weekend. Following directions from a local realtor, my husband Bruce slowly drove our red Volkswagen bus up a steep, deeply rutted, private road.

A vehicle coming up the Plummer’s Hollow Road (Photo by Dave Bonta on Flickr)

A vehicle coming up the Plummer’s Hollow Road (Photo by Dave Bonta on Flickr)

Our three sons—Steve (7), Dave (5), and Mark (2)—were in the back of the bus peering out the windows at the slope and the stream beneath.

“We could really go over the edge there,” Steve shouted excitedly.

“Are we going to live up in the woods? Dave asked hopefully.

After what seemed an interminable time, but in reality was only a mile from the highway, we reached a fork in the road.

“The realtor said to take the left fork,” I told Bruce.

We bumped over a plank bridge, and after a few minutes we emerged from the dark forest into an open field lit by the bright July sun.

A view of the barn taken in 1958

A view of the barn taken in 1958

Rounding the final curve in the road, we passed a tenant house, tool building, and large bank barn on the right and looked up a bluff on our left at a white farm house surrounded by black locust and black walnut trees. At the base of the bluff was an old stone springhouse.

It didn’t take us long to decide to buy the property, and we’ve never regretted it. We were young then, and Bruce had plenty of energy to tackle the repairs of old buildings that needed many renovations, including roofing the barn and installing heating ducts to the second floor of our home.

I was so impressed by the natural beauty of our surrounding acres that I began a career as a natural history writer based on my observations of our unique property.

Dave, left, and Steve examine an insect in 1971

Dave, left, and Steve examine an insect in 1971

Our sons became amateur naturalists and eager explorers of the woods, stream, old fields, and even the rock slides of the mountain.

Much has changed in 50 years, both for us and our sons. We have grown old and our sons middle-aged. They have stayed in our guesthouse, sometimes for months and even years at a time, and have revisited old haunts of their childhood. All three have retained a love and interest in the natural world wherever they have lived.

Bruce retired from his librarian position at Penn State University’s Library more than two decades ago, and much of the repairs and upkeep of our home, property, and access road are now done by our caretaker couple.

But I keep obsessively walking, recording, and observing the natural world and the many changes I have seen here over the last half century. I’ve kept a nature journal, written innumerable columns and articles in newspapers and magazines and five books about our mountain home. My sons and I have lists of the plants and wildlife we have observed on our square mile of mountain land and just last spring, summer, and fall Mark added considerably to our bird list. Dave’s specialties have been trees and wild plants, and Steve’s have been birds and insects. Our caretakers, with their trail cams and own observations, also have added to our knowledge of what is happening here.

During our first decade, our bird feeders attracted dozens of evening grosbeaks and American tree sparrows as well as common winter birds such as tufted titmice, black-capped chickadees, and dark-eyed juncos, and one year we even had an immature red-headed woodpecker and a hen pheasant. Even though folks all over Pennsylvania last fall reported grosbeaks, not one came here, our tree sparrow numbers are now between two and four for most of the winter, and we’ve never seen another hen pheasant or red-headed woodpecker at our feeders.

A hen turkey on her nest (Photo by Mark)

A hen turkey on her nest (Photo by Mark)

But Mark established last year that we continue to host most bird species we recorded that first decade, although their numbers have declined. However, our wild turkey numbers have increased greatly since then and only a few years ago bald eagles became a common sight flying above First Field.

That first decade we had many mid-sized mammals—woodchucks, opossums, raccoons, stripped skunks, red and gray foxes. But in the 1980s the first black bears arrived, followed by eastern coyotes in the 1990s and fishers in this century. Our caretakers, a few of our hunters, and our sons have seen bobcats but so far I have not.

We always have had many eastern cottontails and white-tailed deer, numerous mice, shrew, and vole species, least, long-tailed and ermine weasels, gray, fox and red squirrels, eastern chipmunks, porcupines, and mink, altogether over 40 mammal species, but a deadly fungus disease from Europe has killed most of our bat species this century.

Our greatest losses, in addition to the bats, have been tree species. When we first arrived here, a large butternut tree, also known as “white walnut,” grew in the guesthouse yard, and we found a couple more scattered throughout our forest. But in a few years they died from an infection caused by an imported fungus. They produced nuts consumed by both humans and wildlife and they were tastier than their close relation, the still-thriving black walnut trees.

Dave’s photo of gypsy moth cocoons (On Flickr)

Dave’s photo of gypsy moth cocoons (On Flickr)

Then, in the early 1980s, the imported gypsy moth caterpillars defoliated all of our oak trees and other species except for tulip trees. They even ate the needles of the Norway spruces we had planted at the top of First Field in the spring of 1974. Luckily, we had only one bad year and most of the trees recovered.

By the 1990s we began to hear more about invasive diseases and insects coming from Europe and Asia. At the same time, the adjacent property of 150 acres was logged. We managed to acquire it afterwards, but we were not able to stop the invasion of Japanese barberry, privet, tree of heaven, mile-a-minute, and Japanese stiltgrass there, although last autumn our hunters took a few mornings to rescue First Field from those invasives.

Worst of all the invasives are the hemlock woolly adelgids sucking the life from our eastern hemlocks beside our stream and the even more rapid killing this last decade of our ash trees by emerald ash borers, still another Asian import. First identified in North America in 2002, and in western Pennsylvania in 2007, they have attacked all North American ash species including those in our forest and backyard.

All of these tree species provided food and cover for wildlife and coupled with changes in our weather patterns, wildlife food here has been scarce. Last winter, for instance, there were no wild fruits and few acorns and black walnuts. Even the Norway spruces, white pines, and remaining eastern hemlocks produced no cones.

A female wood duck on our vernal pond (Photo by Mark)

A female wood duck on our vernal pond (Photo by Mark)

Still, our wildflower species have mostly survived, except for a couple orchid species that came and went, and our reptile and amphibian species are still here, including wood frogs in our series of large and small vernal ponds on Sapsucker Ridge that have developed and spread over the last couple decades. Mark even recorded wood ducks there last spring.

And then there are my memories. As I walk our trails, I can recall the animals and plants I have seen along every one. In the hemlock-shrouded, so-called “dark place” by our neighbor, I saw my first fisher, a large male heralded by a flock of protesting songbirds as he came down to drink from the stream.

Off Laurel Ridge Trail, where I was sitting among the mountain laurels listening to a hooded warbler, I saw my first black bear come up the ridge, dip its face down between a double oak tree to drink, and then unknowingly headed straight toward me. When it was about 15 feet away, I stood up slowly and it stopped and stared as I spoke quietly to it. Instead of running away, it paralleled my walk along Laurel Ridge Trail continually peering at me, before finally running off.

Once I saw a mother bear and four cubs near the stream, but they never saw me above them on Rhododendron Trail and I quietly watched them until they wandered off. From across the Far Field for two springs I watched a red fox den. Another year I followed behind four coyote pups as they scampered along Sapsucker Ridge TraiI, and later I watched them playing in front of the spruce grove.

I remember releasing the first eastern golden eagle that had been live-trapped by researchers from a blind on our rock slide. When I let her go, she flew off slowly, then landed on a nearby white pine tree, before flying away.

A swallow-tailed kite in flight (Photo by Andy Morffew on Flickr, Creative Commons license)

A swallow-tailed kite in flight (Photo by Andy Morffew on Flickr, Creative Commons license)

And then there was the spring morning when I reached the spruce grove and something made me look up in time to see a swallow-tailed kite circling above the grove higher and higher.

Never Enough of Nature by Lawrence Kilham has a title that has been my mantra throughout my life. There is always more to learn and no lifetime is long enough to grasp even a small understanding of the natural world of a central Pennsylvania mountain.

 

Wild Parenting

June is a month when I often observe wild parenting during my walks. On the first day of June last year I was halfway down Pit Mound Trail when a doe ran off. Something in the way she moved made me believe she had a fawn nearby. I walked off-trail to look for it in the underbrush, but I couldn’t find it.

Fawn near Pit Mound Trail (photo by Mark Bonta taken June 1, 2020)

Fawn near Pit Mound Trail (photo by Mark Bonta taken June 1, 2020)

I turned around to retrace my steps, my feet crunching in the dead leaves on the forest floor. When I returned to the trail, I was surprised to see a wobbly-legged fawn directly behind me.

“I’m not your mother,” I said quietly to it over and over even as it came close to me and sniffed both my legs.

I tried to resume my walk alone, but the fawn followed at my heels. Apparently, a fawn doesn’t imprint as easily on its mother as animals do that spend most of their time with their mothers, according to Leonard Lee Rue III in his book The Deer of North America. And while a doe will return to nurse her fawn, she mostly stays away from it to keep predators from scenting her and finding her offspring.

A fawn nursing (Photo by James St. John on Flickr, Creative Commons license)

A fawn nursing (Photo by James St. John on Flickr, Creative Commons license)

A fawn will sometimes try to nurse any doe if it is hungry, and if it tries to nurse a doe that is not its mother, the doe will sniff the fawn carefully and will either walk away or hit the fawn with her head or forefoot.

Rue recounts watching a doe give birth and after she ate the afterbirth, she licked the fawn dry and then nursed it. Since that doe was living on a deer preserve, she was comparatively tame and allowed Rue to take photos. But the fawn tottered to its feet and went over to him. Rue asserted that the fawn had approached him because he was moving.

It would have been very easy for him to imprint the fawn, he thought, so he moved quickly away and the fawn returned to the resting doe. Furthermore, Rue maintained that the fawn had been attracted to his moving because does move their offspring from their birthplace as soon as they can walk at about 18 minutes of age.

I didn’t know all this at the time, but I did wonder if that explained why the fawn continued to follow me and that it had sniffed around my legs in search of milk.

The fawn and I continued to descend Pit Mound Trail a couple hundred feet to Ten Springs Trail. There I turned right in the direction the doe had run. Still, I couldn’t shake my little shadow.

Then, after a few minutes, the fawn must have decided I wasn’t its mother after all, and it went down the wooded slope below the trail. I watched from above as it sniffed and examined a couple likely places to settle down. Finally, it curled up beneath a shady tree beside a fresh clump of squawroot.

I was hopeful that the doe would find her fawn since it wasn’t far from where she had run when I had disturbed her. Also, I had been careful not to touch the little creature because Rue claimed that about five percent of does will abandon their fawns if they detect human scent on them.

A porcupette (Photo by California Department of Fish and Wildlife on Flicker, Creative Commons license)

A porcupette (Photo by California Department of Fish and Wildlife on Flicker, Creative Commons license)

A porcupine mother has a different approach to caring for her offspring. Her porcupette follows her when she goes off to forage in the night and lies down at the base of her parent’s feeding tree to wait for her. During the day, while her mother sleeps high in a tree, the porcupette stays hidden under logs or in the base of a tree nearby. But after six weeks of age, the porcupette travels off and finds different trees to rest in during the day, and the mother travels to find her porcupette every night. Often they forage together.

Here on our mountain, we see porcupettes wandering around on their own during the day. Last June 14, I walked down our hollow road. A porcupette walked into the road in front of me and appeared to be eating gravel. Since porcupines crave salt, especially in spring, I thought that might be what it was after, even though we never put salt on our private road. But our caretakers, their family and ours, drive on salted roads during the winter, and I wondered if salt had been left on our road from our tires.

Several researchers over the years in Alaska, Arizona and the Catskills in New York state have watched porcupines lick or try to eat salt-encrusted mud, sand, or even chew on wood or animal bones and all have been impregnated with salt.

The porcupette at last sensed my silent scrutiny and looked up. Then it retreated to the stream bank side and belly-flopped into the greenery, thinking it was hidden. I said to it several times that I wouldn’t hurt it and continued down the road. When I returned to the spot later it was gone. I assumed its mother was sleeping in a hemlock tree and the porcupette had been left on its own.

A brown thrasher in Plummer’s Hollow (Photo by Mark Bonta)

A brown thrasher in Plummer’s Hollow (Photo by Mark Bonta)

Bird parenting includes many strategies, and last June our forest was filled with bird species disturbed by my presence. One June morning I tried to sit on Alan’s Bench at the edge of the Norway spruce grove and was heartily scolded on and on by a pair of birds hidden in the spruces. Finally, I stood up, looked around, and caught a glimpse of one of the affronted birds—a brown thrasher. It must have had a nest somewhere on the ground in the thick brush near the bench.

A black and white warbler in Plummer’s Hollow (Photo by Mark Bonta)

A black and white warbler in Plummer’s Hollow (Photo by Mark Bonta)

That same day I made a stop at Coyote Bench on the Far Field Road. I watched what looked like a young black-and-white warbler foraging in the trees. Then there was scolding behind me as a male black-and-white warbler appeared with food in his beak. He came close enough that I could see that he had a caterpillar. He flew from branch to grapevine back and forth and then flew off. Next, a female black-and-white flew in with food in her beak. She was not as brightly-colored as the male, but not as dull-colored as the first bird I saw. From this I assumed the black-and-white warblers had been feeding at least one fledgling and possibly more hidden in the tangle of shrubs and vines in front of the bench.

But the Norway spruce grove remained the center of bird family activity. On June 17 a chipping sparrow emerged from a cluster of spruces with a large, green caterpillar in its beak. Both that bird and another chipping sparrow flew around as if they had a nest somewhere close by in one of the smaller spruces at the edge of the grove.

A black-capped chickadee in Plummer’s Hollow (Photo by Mark Bonta)

A black-capped chickadee in Plummer’s Hollow (Photo by Mark Bonta)

And late in June for several days I watched a family of black-capped chickadees as they fed their fledged young on a tangle of large fallen spruce trees where I found all of them foraging on subsequent days. Unlike the many birds that protested my presence, they didn’t act with alarm as I sat nearby.

Then, near the end of June, Guesthouse Trail became a center for concerned bird parents. One morning I heard a “chirr, chirr, chirr” from a Cooper’s hawk that dove low at me, first from one side of the trail and then the other. Assuming it had a nest in the area, first I followed a deer trail in one direction and the Cooper’s hawk was quiet. But when I went in the opposite direction, the bird’s protests grew louder. Yet although I peered into every large treetop, I could not find the nest.

I wasn’t worried about aggression from the large raptor because years ago a Cooper’s hawk pair had allowed me to observe their nest life from a hill a few hundred feet above the nest and often they sat quietly in the trees beside me. But every individual bird, as well as species, can behave differently from each other, as I soon learned.

A blue-headed vireo in Plummer’s Hollow (Photo by Mark Bonta)

A blue-headed vireo in Plummer’s Hollow (Photo by Mark Bonta)

On that day, as I neared the top of Guesthouse Trail, I heard songbird protesting and when I pished, I was hit a glancing blow atop my head by one songbird, as another flew about on low limbs of saplings and scolded. To my surprise, they were blue-headed vireos. Years ago, I had found and observed a blue-headed vireo on her nest and had never been attacked.

Two days later, I walked up Guesthouse Trail again. A Cooper’s hawk verbally scolded me and dove close to me three times, but that day a blue-headed vireo scolded but didn’t attack me. Still, I stayed clear of that trail for several days. But I never saw either the Cooper’s hawks or the blue-headed vireos again.

Different strokes for different mammal and bird parents. Yet all those creatures used different but effective methods to keep predators away from their vulnerable young.