June is often the most exciting month of the year. Then I can count on close encounters with black bears on our trails. Not only are last year’s cubs on their own, but their mothers are being hotly pursued by eager males.
We also add new species to Bioplum, a natural inventory of our property. But last June 5 we added a record three species in one day. Our caretaker family — Troy and Paula Scott — found a northern brown snake in their yard and promptly photographed it. Formerly named DeKay’s brown snake—Storeria dekayi dekayi—its species name still honors nineteenth century naturalist James Edward DeKay. According to Amphibians and Reptiles of Pennsylvania and the Northeastby Hulse, McCoy, and Censky, the northern brown snake “reaches its greatest densities in and around abandoned human habitation.” That made sense because the Scotts’ home is directly above the derelict home of our deceased neighbor, Margaret McHugh.
Later in the day, the Scotts saw a painted turtle on our road. It was probably a female looking for a nesting site because from late May to early July they leave slow-moving water in search of a gentle slope exposed to the sun in which to deposit their eggs.
I was disappointed to miss those two new species, but I was able to see the third new one of the day. Our friend, Lucy Boyce, who specializes in native plants, spent several hours with our son Dave in our three-acre deer exclosure, searching for new plants. The phone rang, and Dave told me to come and see two wild coffee plants — Triosteum perfoliatum — blooming in the wet, overgrown section of the exclosure.
Frankly, I had never heard of wild coffee, also called perfoliate horse gentian, fever-root, feverwort, and tinker’s-weed. Its erect stem has several pairs of large, opposite, oval, pointed leaves that meet and surround the stem. In the axils of the leaves grow reddish-brown or greenish elongated, bell-shaped flowers. It likes rich, moist woods and thickets, such as ours, and flowers in May and early June.
But even better than finding new species and seeing bears on our trails last June was my unexpected encounter with a rare animal. On a gorgeous day in mid-June, I slowly ascended Big Tree Trail on Sapsucker Ridge. It was a pleasant 63 degrees at 9:00 a.m. as I continued my walk along our forested ridgetop.
Suddenly, I saw what I thought was a small gray squirrel coming towards me. It ran to a tree, climbed about three feet from the ground, and clung to the tree trunk. But instead of a fluffy tail, its tail was very long, thin, and sparsely-haired. Then it turned its head toward me and it didn’t look like the face of a squirrel, but like that of an overgrown white-footed mouse. I had only time to notice its large, roundish, shell-shaped ears, and its big, dark eyes before it jumped off the tree and disappeared. But I was almost certain that it was an Allegheny woodrat.
Years ago, on October 4, 1989 — my husband Bruce and our eldest son Steve had a perfect view of an Allegheny woodrat while driving up our hollow road at 10:45 p.m. What the woodrat was doing there was a mystery because its habitat, as described then in the literature, didn’t fit the supposed requirements of an Allegheny woodrat. They live in caves and talus slopes and the nearest talus slope on the far side of Sapsucker Ridge was farther away than a woodrat’s range.
Their intriguing sighting led me to learn more about this native packrat. And, the following autumn, Bruce and I accompanied PGC Wildlife Technician Cal Butchkoski, as he climbed a hundred foot high rock outcropping in an old-growth hemlock forest. As part of a study by the Game Commission that began in 1982, he had set 40 live traps baited with apples for woodrats in the caves and crevices the evening before and wanted to release any captives as quickly as possible to minimize stress on the animals.
But when he released a male on my lap so Bruce could take photographs, the woodrat seemed anything but stressed. He spent several long, camera-clicking minutes climbing on my jean-clad legs before leaping gracefully to the floor of the cave and disappearing under a dead pile of leaves that was, in reality, his home. Made of sticks, shredded bark, grass and dried leaves, woodrat homes range in shape from cone-shaped to flattened.
At that time, Butchkoski showed us pencil-eraser-sized droppings in its latrine site under a nearby ledge which serve as a signpost for anyone looking for woodrats. These droppings last for decades and, depending on their condition, researchers can determine whether or not woodrats are still in residence. Needless to say, Bruce and our sons combed the talus slopes on Sapsucker Ridge but didn’t find any latrines.
While Bruce’s and Steve’s sighting seemed unusual because of the woodrat’s distance from its rock habitat, mine was equally surprising because Allegheny woodrats are nocturnal. On the other hand, even though it has been 20 years since I last looked into the ecology of Allegheny woodrats, researchers are still puzzled by many aspects of their lives.
Much has changed too. Back then the Allegheny woodrat was considered to be a subspecies of the eastern woodrat (Neotoma floridana) which ranges south to Florida and west to Colorado. It had lost its original species status Neotoma magister in 1957 when researchers had relegated it to subspecies status based on comparative studies of eastern woodrat skulls and skins. But using new molecular methods, researchers conducted mitochondrial DNA analyses of 114 woodrats from 33 locations and proved that Allegheny woodrats are indeed a separate species from eastern woodrats. In 1997 they were once again listed as Neotoma magister in the Revised Checklist of North American Mammals.
Furthermore, Allegheny woodrats are ecologically distinct from eastern woodrats because they live almost exclusively in caves, boulder fields, and talus slopes consisting of sandstone and/or limestone—so-called rock habitats. They build their nests on cave ledges, like the one we saw with Butchkoski, or in rock crevices
Females claim the best habitats to construct their nests and raise their young. They breed as early as mid-March in Pennsylvania, and, after about 35 days, give birth to one to four naked, blind young. Their eyes open at two-and-a-half weeks, and they nurse until they are a month old. Then, although they may remain with their mother for a while, they begin to do their own foraging for leaves, fruit, mast, fungi, and even twigs. Once they are on their own, they build individual nests, because woodrats are solitary animals except during the breeding season. They don’t hibernate so they are busy collecting and drying food, such as fungi and fern fronds, to stuff into crevices for winter consumption. For the most part, they “exhibit high site fidelity and low dispersal rates,” according to researchers.
But Dr. Janet Wright and her students of Dickinson College, radiotracked an adult male for two years. He moved suddenly 3.6 miles along a ridgetop to a new site. She also discovered that woodrats will travel “considerable distances beyond the protection of rock slides in search of food and mates.”
Another researcher, Dr. Petra Bohall Wood, in West Virginia, found that woodrats, particularly males, do move away from their birth site between their juvenile and adult years. From these studies and others I looked at, I hypothesized that the woodrat I encountered still had its grayer youngster coat and was either searching for food or dispersing. The previous fall had been a terrific mast year when woodrats are especially prolific so perhaps young woodrats were more inclined to find a new home. And that woodrat Bruce and Steve saw years before was probably also dispersing.
There is another extensive talus slope less than a mile away on our neighbor’s property. Unfortunately, it had been heavily logged the previous year which may have sent any woodrats living there in search of a new home, because recent studies seem to indicate that the best habitat surrounding rocky areas should include an oak/hickory forest rich in mast. In fact, a large intact forest buffer 1.2 miles from the forest edge is ideal, something we don’t have below our talus slopes but do on our ridgetop.
Pennsylvania is thought to have five percent of the world’s population of Allegheny woodrats. Most of the population is now in the Appalachian south, although more study of populations needs to be done in those areas. It has gone extinct in Connecticut, New York, and the southeastern portion of Pennsylvania where it used to be common. Pennsylvania has relegated Allegheny woodrats to threatened status, and they are protected under the Game and Wildlife Code. Game Commission biologists, including Butchkoski, have been engaged in long-term monitoring to find out how dense populations are at each site. Previously, from 1982 to 2006, Pennsylvania biologists conducted 1,255 surveys at 802 habitat sites and found evidence of current or former woodrat occupation at 443 sites. Of those sites, 246 were still active and 197 were not. They hope to maintain breeding populations in the Appalachian Plateau, Ridge and Valley Province, and the upper Susquehanna River drainage.
But why are Allegheny woodrats disappearing? That question has haunted researchers from the beginning, and over the years a number of suggestions have been made. After all, their rock habitats are not very accessible to most people. Researcher Kathleen LoGludice summed up biologists’ hypotheses in The Allegheny Woodrat; Ecology, Conservation and Management of a Declining Species edited by J.D. Peles and Janet Wright. First and foremost, is a decrease in food that began with the disappearance of the predictable, yearly crop of American chestnuts and then the woodrats tried to adjust to boom-and-bust acorn cycles, especially during years of heavy gypsy moth infestation when oaks are too stressed to produce any acorns.
Habitat fragmentation caused by new or widened roads, quarries, industrial wind farms, utility lines, communication towers, and natural gas drilling rigs makes it increasingly difficult for woodrats to move safely from one rock habitat to another.
Finally, as packrats, they collect both edible and inedible material. One “midden,” as it is called, examined in Centre County in 1941, contained three quarts of deer pellets. Three other middens discovered by the same researcher yielded a baseball cover, can labels, a cigarette pack, cloth, a shoe heel, yarn, rusty tin cans and pieces of string. None of these items pose a threat to Allegheny woodrats. But as their habitat fragments and residential and agricultural fields move closer, generalist species, especially raccoons, increase. With raccoons come raccoon roundworm which is fatal to woodrats that collect and eat raccoon feces.
Raccoons also prey on woodrats as do great horned owls, coyotes, weasels, fishers, and black rat snakes. We certainly have abundant numbers of these creatures on our property. And hopefully my sighting is a sign that we have a population of Allegheny woodrats too.
For more information on this charismatic animal, consult the Pennsylvania Game Commission website. The Allegheny Woodrat: Ecology, Conservation and Management of a Declining Species, edited by J.D. Peles and Janet Wright, is also an excellent source.
Sometime in early April, I hear the ringing song of a Louisiana waterthrush near our Plummer’s Hollow stream. One of the first neotropical migrant birds to return, he comes winging in from as far south as northern South America and southern Cuba.
This handsome brown warbler, his whitish breast streaked with brown, looks more like a thrush than a warbler. Along with his congener, the northern waterthrush, the Louisiana waterthrush wades on long, pink legs in streams and bobs his tail and rear like a spotted sandpiper.
I spend a lot of time along our mile-and-a-half, first order stream, watching and listening to these fascinating birds. By mid-April there are usually four males staked out along the stream singing, defending their long, narrow territories and courting the returning females. It’s important to catch their singing early, though, because as soon as they pair up, the males slow down and almost stop singing.
A favorite place for waterthrushes is below our Waterthrush Bench, and last spring their activity was especially interesting. On April 18 I watched two singing waterthrushes bobbing their tails as each one tried to stay above the other when they landed on mossy logs, tree branches, and in the stream itself. They moved several hundred feet upstream before flying back down stream, and I wondered if they were two males in a territorial dispute or a pair involved in a courtship ritual.
The last day of April, as I sat on Waterthrush Bench, I watched a waterthrush as it poked about in the puddles of a backwater, pulling aside rotted leaves in what ornithologists call ”leaf pulls” as it searched for food. Although 89 to 98% of waterthrush feeding consists of quick, jab-like strokes called “picks,” “leaf pull” is an alternate strategy. In both cases, they are searching for aquatic insects and invertebrates. According to one study in northeastern Connecticut, before the leaves emerge waterthrushes engaged in “leaf pull” 42% of the time and “picks” 54%, but “leaf pulls” decreased and “picks” increased as their breeding season progressed and trees leafed out.
After my waterthrush stopped “leaf-pull,” it waded about belly-deep in the water. Then it flew up on a moss-covered log spanning the backwater to preen. All the while it preened its breast, neck, belly and under its tail, that tail kept pumping as regularly as a metronome.
Years ago, again on the last day of April, in the deepest part of the hollow, which is overhung with hemlock and beech trees, I walked quietly downstream and saw a pair of Louisiana waterthrushes in the water in front of me. They didn’t notice me when they turned over wet leaves in the stream. As I followed and watched, the male walked a couple yards behind the female. Unlike most warbler species, the male and female look alike, so I was relying on a description of this courtship tactic by ornithologists. The male made a “zizzing” sound and fed the female. Then they continued alternately foraging and poking at the stream bank. After I followed them for fifteen minutes, they suddenly saw me, chipped warning notes, and flew off.
Last spring, on the fourth of May, a Louisiana waterthrush swayed and scolded on a branch overhanging the road near Waterthrush Bench. Somewhere nearby in the road or stream bank there must have been a nest with eggs. I remembered my son Steve’s discovery a quarter of a century ago of a nest he found in the road bank as he walked up the road. The female flushed in front of him and performed her broken wing act. Following his description, I easily found the nest four feet from the ground, tucked in over a rock well-padded with dead leaves. An overturned sapling provided a roof above the five whitish eggs spotted with irregular brown spots that lay in a nest of dried grasses.
The nest had been built on the south side of the ravine by both parents. They dug a shallow cup in the bank’s soil and hauled in fallen leaves from the forest floor to fill the cup and provide a short pathway to the nest, a task that ornithologists say takes three to four days. Incubation by the female lasts 12 to 14 days and the altricial nestlings go from naked to fully feathered in nine or 10 days when they fledge. The nest Steve found did produce not only nestlings but fledglings, and I saw both the nestlings and their fledging.
Since then, we’ve never found another nest but suspect that most are along the stream bank and in the interstices of uprooted trees, which are the usual nesting places for Louisiana waterthrushes.
The bird that scolded me last May then waded into the stream and poked up food from the wet moss on the rocks or from the swiftly-flowing water. Like the dippers of the western United States, Louisiana waterthrushes are wedded to clean, running streams. It jabbed quietly in the crevices, living its enviable life in the moving water whose babble blocks out all other sounds.
Its affinity for water makes it an ideal species to use when assessing the ecological health of streams, researchers discovered at the Powdermill Nature Reserve in southwestern Pennsylvania. This biological field research station of the Carnegie Museum of Natural History in Pittsburgh is best known for its long-running, year-round, bird-banding program begun in 1961 by Robert Leberman.
Leberman’s assistant, Robert Mulvihill, now at the National Aviary in Pittsburgh, along with Leberman, chose the Louisiana Waterthrush as a model for looking at bird populations back in 1996. After all, two streams — Powdermill Run and Laurel Run — hosted Louisiana waterthrushes. But those two streams differed in one important aspect. Powdermill Run’s water has a neutral pH of 7, but Laurel Run’s was an acidic pH of 5, the result of acid mine drainage from a small, hand-dug coal mine on nearby private land.
More than 50 years after this 30-year-long disturbance, it still impacts Laurel Run despite the best efforts of a local watershed association that installed a Successive Alkalinity Producing System to filter water through organic material and limestone into a settling pond to lower the acidity and remove heavy metals, as well as an attempt by the Department of Environmental Protection, using bioremediation techniques, to further improve stream quality.
Consequently, Louisiana waterthrushes breed early and abundantly on Powdermill Run and late and sparsely on Laurel Run because of the lack of macroinvertebrates, especially caddisflies and mayflies, in the acidic Laurel Run. In fact, by 2009, no waterthrushes bred on Laurel Run, yet over the more than ten years of monitoring, Powdermill Run remains a hot bed of successful, breeding waterthrushes. Apparently, the availability of the proper food — namely macroinvertebrates that favor clean water — is very important for attracting breeding Louisiana waterthrushes.
This study also made some natural history discoveries about Louisiana waterthrushes, according to Mulvihill, who directed the research. The males of this supposedly single-brooded, monogamous species occasionally engage in opportunistic polygyny, defined as pairing with two females at the same time. Eight times during the study, waterthrush pairs re-nested or double brooded after their first successful fledging of young. One female that started out on Laurel Run in her first year of breeding, transferred to Powdermill Run and brought off successful families for at least eight years.
Today, Steven Latta, Director of Conservation and Field Research at the National Aviary, continues Louisiana waterthrush research, studying one of its wintering grounds in the Dominican Republic. He’s especially interested in how water quality there affects the survival of the birds and whether or not they return to their breeding grounds. He also wants to use the species to understand what affects neotropical bird populations throughout the year. He writes, in a recent article in Birding, that “in addition to acidification, breeding success is likely linked to sedimentation and other forms of stream contamination, combined with the loss of surrounding vegetative cover in the riparian corridor… Preliminary results suggest that older, more mature forests with relatively high canopy cover, coupled with perennial streams that do not run dry in mid-summer droughts, are key drivers to reproductive success for such bird species.”
Back at Powdermill, scientists are now concerned about the impacts of natural gas drilling on water quality, macroinvertebrates and Louisiana waterthrushes. And they have joined other ornithologists in the state to study the affects of hydraulic fracturing on streams throughout Pennsylvania. They hope that birders will help by counting waterthrushes along streams and reporting their numbers to their local watershed association. Two territories per kilometer are considered a healthy number of waterthrushes along a stream.
Louisiana and northern waterthrushes were once lumped along with ovenbirds into the genus Sieurus, which means “to shake or move the tail,” but for decades Dr. Kenneth C. Parkes, the late curator of birds at the Carnegie Museum of Natural History, argued that the waterthrushes should be separated from ovenbirds. They differ too much in behavior, singing, structure, the way they move, their juvenile plumage and how long they keep it, as well as other differences that only ornithologists could sort out.
It took a Ph.D student in the Molecular Systematics Laboratory at the Swedish Museum of Natural History in Stockholm, George Sangster, who admired Parkes’s work, to prove his point. Using genetic analyses, he discovered that ovenbirds were only distantly related to waterthrushes.
On the strength of his work, the North American Classification Committee of the American Ornithologist’s Union agreed to put the waterthrushes in their own genus. Furthermore, they accepted Sangster’s name — Parkesia — in honor of Kenneth C. Parkes because of “his lasting contributions to avian taxonomy, molt terminology, hybridization and faunistics.”
Sangster finished his manuscript about his discovery in the Bulletin of the British Ornithologists’ Club in late July of 2007 and “hoped to inform Dr. Parkes about my intention of naming a genus after him,” Sangster told Paul Hess who wrote about this in PSO Pileated, The Newsletter of the Pennsylvania Society for Ornithology. “It was when I looked on the Internet for a contacting address that I found out that he had passed away only a week before.”
Only three other Pennsylvanians have been honored with a bird genus — William Bartram, Thomas Say, and Alexander Wilson. All of them lived and worked in the late eighteenth and early nineteenth centuries, and all were residents of Philadelphia.
How sad that Parkes never knew of his genus. But how serendipitous that one of the species Leberman and Mulvihill decided to study at Powdermill has not only become important in stream ecology but also honors a fellow western Pennsylvanian who, like them, devoted his life to the study of birds.