Mice and Voles (Cricetidae) – LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED

May 13, 2025May 13, 2025

Nest Builders at Work

For many animals, an adequate shelter is paramount for their successful reproduction. Here’s a sample of some of the lower Susquehanna valley’s nest builders in action…

Pileated Woodpecker Excavating Nest — Many of our year-round resident bird species get a head start on the breeding season as cavity nesters. Some of these mated pairs use naturally occurring hollows, while still others take advantage of the voids left vacant by the more industrious previous occupants. Woodpeckers in particular are responsible for excavating many of the cavities that are later used as homes by a variety of birds and mammals to both rear their young and provide winter shelter. Pileated Woodpeckers, like other members of the family Picidae, have an almost mystic ability to locate diseased or insect-infested trees for selection as feeding and nesting sites. In this composite image, a pair is seen already working on a potential nursery during mid-January. After use by the woodpeckers, abandoned cavities of this size can become nesting sites for a variety of animals including bees, small owls, Great Crested Flycatchers, Wood Ducks, Hooded Mergansers, and squirrels.

Downy Woodpecker at Nest — After use as a nesting site, a void excavated by Downy Woodpeckers can be occupied in subsequent years by chickadees, titmice, nuthatches, wrens, and other cavity-dwelling species.

Muskrat with Leafy Twig — This Muskrat (*Ondatra zibethicus)* with a leafy twig in tow takes advantage of spring’s new growth to construct or repair its house,…

Muskrat House — A Muskrat house in March. In the absence of leafy twigs, dried cattail stems will suffice. As it ages and decays, the house’s organic matter generates heat and makes an ideal location for turtles to deposit and hatch their eggs.

Soon after Neotropical migrants begin arriving in the forests of the lower Susquehanna watershed, they begin constructing their nests. The majority of these species build “outdoors”, not within the confines of a tree cavity. Here we see a Wood Thrush with its bill full of dried leaves and other materials…

Wood Thrush Nest — …ready to line the cup of its nest in the fork of a small understory tree.

Though it often arrives during early April after spending the winter in sub-tropical and even some temperate climes, the Blue-gray Gnatcatcher must wait to start construction of its nest until many of the Neotropical migrants arrive in early May.

Blue-gray Gnatcatchers — Back at the nest site…

Baltimore Oriole with Nesting Material — Baltimore Orioles weave one the most unique nests of any species occurring in eastern North America.

Baltimore Oriole Nest — Unfortunately for them, man-made litter can often seem to be the ideal material for binding the nest together. In an area only sporadically visited by anglers, this oriole had no trouble finding lots of monofilament fishing line, trash that can fatally entangle both adult and young birds of any species. If you see any fishing line at all, please pick it up and dispose of it properly.

Baltimore Oriole — Always keep an eye open for fishing line and get it before the birds do!

Like many other avians, male Brown-headed Cowbirds are now relentlessly pursuing females of their kind.

Watching and waiting. The Indigo Bunting evades cowbird parasitism by first recognizing the invader’s egg. They then either add a new layer of nest lining over it or they abandon the nest completely and construct a new one. Some patient buntings may delay their breeding cycle until after cowbird courting behavior ceases in coming weeks.

March 24, 2025March 24, 2025

During Saturday’s Prescribed Fire Demonstration at the Pennsylvania Game Commission’s Middle Creek Wildlife Management Area, we noticed just how fast some species of wildlife return to areas subjected to burns administered to maintain grassland habitat and reduce the risk of high-intensity blazes.

Back Fire Ignition during prescribed burn demonstration. — Pennsylvania Game Commission crews ignite a back fire to contain a prescribed burn along its downwind/upslope perimeter during a demonstration at Middle Creek Wildlife Management Area on Saturday.

Dozens of recently arrived Tree Swallows swept in to patrol for flying insects as the burn was in progress.

Red-tailed Hawks and other raptors, including nocturnal owls, are frequently the first visitors attracted to the scene of a prescribed burn or wildfire. In grassland and successional habitats, they come looking for any vulnerable voles or mice that may be moving about looking for cover.

These three Eastern Meadowlarks spent the morning in the grassland areas adjacent to the prescribed fire site, mostly where a burn had been conducted one week prior. During the demonstration, one even perched and sang from the oak trees in the museum/visitor’s center parking lot.

Following the Prescribed Fire Demonstration, we decided to pay a visit to some of the parcels where burns had been administered one week earlier on the north side of Middle Creek’s main impoundment. We found a surprising amount of activity.

White-crowned and White-throated Sparrows — Apparently feeding upon slightly heat-treated seeds, sparrows were found by the dozens. White-crowned (left), White-throated (right), Song, and Savannah Sparrows were identified.

This Downy Woodpecker was finding something to its liking among the scorched leaves, stems, and twigs.

American Robins seem to find areas with lightly burnt vegetation and ash-dusted soil advantageous for finding invertebrates following a fire.

Mixed Flock of Blackbirds — We found this flock of Red-winged Blackbirds, Browned-headed Cowbirds, and a few European Starlings feeding throughout a grassland field cleared of early-successional growth by a prescribed fire administered one week ago.

Nearby, in an island of unburned grass in the same field, we found yet another Eastern Meadowlark, our fourth of the day. High-intensity agriculture, particularly early hay mowing and pesticide treatments, have mostly eliminated this and other grassland species from modern farms. Management practices like prescribed fire and delayed mowing (no spinning blades until at least early August) can maintain ideal grassland habitat for stunningly colorful blackbirds including nesting Eastern Meadowlarks, Bobolinks, and many other species as well.

American Kestrel at Nest Box — A male American Kestrel at a nest box located among Middle Creek’s warm-season and cool-season grassland habitats, the former maintained by prescribed fire, the latter by delayed mowing.

February 26, 2025April 28, 2025

Winter Survival: Generalists and Specialists

We’ve seen worse, but this winter has been particularly tough for birds and mammals in the Lower Susquehanna River Watershed. Due to the dry conditions of late summer and fall in 2024, the wild food crop of seeds, nuts, berries, and other fare has been less than average. The cold temperatures make insects hard to come by. Let’s have a look at how some of our local generalist and specialist species are faring this winter.

House Sparrows and a House Finch — House Sparrows (bottom) and House Finches (top) are generalists. To survive and thrive, they are adapted to a variety of habitats and types of food. House Sparrows live almost anywhere man-made structures are found. They are true omnivores and will eat almost anything, especially if they see something else try to eat it first. The House Sparrow’s close association with humans has allowed it to become the most widespread and successful living avian dinosaur. On a cold night, they’ll take shelter either within dense vegetation alongside a building or within the structure itself. Though not nearly as cosmopolitan, the House Finch has successfully colonized much of the eastern United States after escaping from captivity as a cage bird in New York during the middle of the twentieth century. Upon being trans-located here from the arid southwest, they adapted to suburbs and farmlands consuming primarily a granivore diet of seeds supplemented with seasonally available berries. They quickly became accustomed to offerings at bird-feeding stations as well. To survive the harsh winters in the northern sections of their range, eastern populations of House Finches are developing a pattern of migration. These movements are most evident in late fall when dozens or sometimes hundreds can be seen heading south over regional hawk-counting stations.

Northern Flicker feeding on Poison Ivy — Though they require dead trees for nesting and as places to find the grubs and adult insects upon which they primarily feed, woodpeckers including the Northern Flicker are generalists, seldom passing by a supply of fruits like these Poison Ivy berries as a source of winter food. Flickers regularly visit suburban areas where they’ll drop by at bird-feeding stations for suet. During the warmer months, they are the woodpecker most frequently seen on the ground where swarms of ants garner their full attention.

The Pileated Woodpecker is seldom found outside of mature forests where it digs relentlessly to remove grubs and other infestations from dead wood. But it is not a true specialist…

Pileated Woodpecker eating Poison Ivy — …it too finds a supply of Poison Ivy berries to be indispensable during a cold winter day.

The Ruby-crowned Kinglet is a generalist, feeding mostly on insects, but also consuming small seeds and some berries, including those of Poison Ivy. It nests well to our north in tall spruces and other evergreens. During migration and in winter, the Ruby-crowned Kinglet may be found in deciduous trees, brush, and tall grass in habitats ranging from forests to parks and suburbia. This male is displaying its seldom-seen red crown.

The Golden-crowned Kinglet, seen here on a Poison Ivy vine, is more of a specialist than the Ruby-crowned species, though the two will often occur in mixed groups during the winter. The Golden-crowned Kinglet nests in Spruce-Fir forests and in conifers within mixed woodlands. Even during migration, and particularly in winter, these birds are seldom found far from a stand of large evergreens within which they find shelter for the night.

The Hermit Thrush’s generalist lifestyle allows it to survive cold season weather in the Lower Susquehanna River Watershed. During summer, it breeds in coniferous and mixed woods from the northern parts of our valley north into Canada and feeds primarily on worms, insects, and other arthropods. During migration and in winter, the Hermit Thrush becomes a regular visitor to deciduous forests, woody parks and suburbs, particularly where a supply of wild berries is available to supplement its diet.

Iconic as it pulls earthworms from lawns during the warmer months, the generalist American Robin is fully dependent upon a crop of berries to survive winter conditions in the lower Susquehanna valley. The drought afflicted wild food crop of 2024 has led to fewer robins spending the season here and has delayed the northward push of migrating birds until the ground thaws and the earthworms make the ground rumble once again.

It’s insects for the nestlings during spring and summer, then berries through the winter for the cheerful Eastern Bluebirds, another generalist species.

American Crows are an excellent example of a generalist species. They’ll go anywhere to find food and they’ll eat almost anything. Like the House Sparrow and several other generalists, they adapt very well to human activity and actually thrive on it. Garbage anyone?

Another career generalist is the widely worshiped White-tailed Deity, a species adapted to nearly all man-made landscapes with adequate vegetation upon which to browse. Pushed to the limit during severe weather, some individuals will consume carrion and even resort to cannibalism.

You might think the Great Blue Heron is a specialist. Nope, it’s an accomplished generalist. Great blues will live, feed, and breed on almost any body of fresh or brackish water. And their diet includes almost anything that swims. In winter, you’ll even see them in fields hunting mice and voles.

The Red-shouldered Hawk is a generalist with a diet ranging from amphibians and reptiles to small rodents and large insects. Mostly regarded as a species of bottomlands, they’ll frequent woodland edges, roadsides, and suburbia during the winter months.

During its periodic winter visits to the region, the American Tree Sparrow feeds on seeds among the grasses and forbs of semi-open country with scattered short shrubs and trees. A generalist species, it will show up at backyard bird-feeding stations, particularly during periods of inclement weather. In summer, the American Tree Sparrow nests in tundra with growths of stunted willows and spruce and their diet includes insects as a source of protein for themselves and their young.

The White-crowned Sparrow has similar winter habitat preferences to the tree sparrows…

White-crowned Sparrows — …it becomes adaptable and something of a generalist when searching for food during bad winter storms.

The Savannah Sparrow is an omnivore favoring insects in summer and seeds in winter. Though very closely tied to its grassland habitat year-round, snow cover can push these birds to enter woodier environs to consume fruits like these rose hips.

Dusk and dawn during the short days of winter are the prime hunting times of a mammal specialist, the Short-eared Owl. Its presence in the lower Susquehanna valley is dependent on two dominant factors: extensive grassland habitat and an adequate population of the owl’s favored food, the Meadow Vole (Microtus pennsylvanicus). The Short-eared Owl’s requirements as a specialist species make finding a suitable place to live difficult. Unlike the generalist birds and mammals that often adapt to the widespread man-made disturbances in the region, populations of specialists frequently become fragmented, reduced in abundance, and subject to extirpation.

The Meadow Vole is a generalist rodent that can be abundant in grasslands, early successional growth, fallow fields, marshlands, and, of course, meadows. They are primarily herbivores, but will occasionally consume insects and other arthropods. Usually nocturnal, some individuals venture out along their surface runways during daylight hours becoming vulnerable to diurnal raptors including kestrels, harriers, and buteos.

Short-eared Owl patrolling a grassland for Meadow Voles — A Short-eared Owl in near darkness patrolling a grassland for Meadow Voles.

The eastward expansion of the Coyote (Canis latrans), a species of western North America’s grasslands and scrublands, and its progressive mixing with the Wolf (Canis lupus) in these eastern extensions of its range, has produced an expanding population of very adaptable generalists we call Eastern Coyotes (Canis latrans var.). These omnivorous canines colonized the Lower Susquehanna River Watershed during the last four decades to replace extirpated wolves as the top-tier natural predator in the region. Their primary diet includes Meadow Voles in grasslands and other small mammals along woodland edges and in successional habitats. Seasonally, they consume the berries of numerous wild plants. Slightly larger than their western ancestors, Eastern Coyotes with the admixture of Wolf genetics can subdue small ungulates. Like other apex predators, they are attracted to vulnerable prey and thus play a crucial role in culling the weak and diseased among their potential quarry species to assure the health and potential of populations of these species as long-term sources of food energy. The benefit to the prey species is however largely diluted in populous areas of the northeast; most venison consumed by Eastern Coyotes here is in the form of road kill. During periods of extended snow cover when small rodents and other foods become inaccessible, Eastern Coyotes, particularly young individuals, will wander into new areas seeking sustenance. Sometimes they venture into cities and suburbs where they explore the neighborhoods in search of garbage and pet foods placed outside the home. (Video clip courtesy of Tyler and Grace Good. Click image to view.)

Wildlife certainly has a tough time making it through the winter in the lower Susquehanna valley. Establishing and/or protecting habitat that includes plenty of year-round cover and sources of food and water can really give generalist species a better chance of survival. But remember, the goal isn’t to create unnatural concentrations of wildlife, it is instead to return the landscape surrounding us into more of a natural state. That’s why we try to use native plants as much as possible. And that’s why we try to attract not only a certain bird, mammal, or other creature, but we try to promote the development of a naturally functioning ecosystem with a food web, a diversity of pollinating plants, pollinating insects, and so on. Through this experience, we stand a better chance of understanding what it takes to graduate to the bigger job at hand—protecting, enhancing, and restoring habitats needed by specialist species. These are efforts worthy of the great resources that are sometimes needed to make them a success. It takes a mindset that goes beyond a focus upon the welfare of each individual animal to instead achieve the discipline to concentrate long-term on the projects and processes necessary to promote the health of the ecosystems within which specialist species live and breed. It sounds easier than it is—the majority of us frequently become distracted.

Being an individual from a population of a very successful generalist species is no guarantee of survival. This Eastern Gray Squirrel fell from a tall tree when the limbs became ice covered during a storm earlier this month. Just a freak accident? Maybe, but mistakes like this are often fatal in the natural world. This squirrel’s passing may seem brutal, but it provides a better opportunity for other squirrels and animals that share its food and cover requirements to make it through the winter. And those survivors that didn’t suffer such a fatal mistake or, more importantly, don’t possess a vulnerability that may have contributed to such a mishap will have a chance to pass those traits on to a new generation. This squirrel as an individual is gone, its species lives on, and may be stronger for its passing.

Prescribed Burn of a Grassland — Pennsylvania Game Commission crews maintain a grassland ecosystem for Short-eared Owls and other specialists using prescribed fire to prevent succession beyond its earliest stages. Among the additional specialist species benefiting from this management tool are Monarchs and other butterflies whose host plants survive early-season fire, but not competition with woody vines, shrubs, trees, and invasive herbaceous growth.

On the wider scale, it’s of great importance to identify and protect the existing and potential future habitats necessary for the survival of specialist species. And we’re not saying that solely for their benefit. These protection measures should probably include setting aside areas on higher ground that may become the beach intertidal zone or tidal marsh when the existing ones become inundated. And it may mean finally getting out of the wetlands, floodplains, and gullies to let them be the rain-absorbing, storm-buffering, water purifiers they spent millennia becoming. And it may mean it’s time to give up on building stick structures on tinderbox lands, especially hillsides and rocky outcrops with shallow, eroding soils that dry to dust every few years. We need to think ahead and stop living for the view. If you want to enjoy the view from these places, go visit and take plenty of pictures, or a video, that’s always nice—then live somewhere else. Each of these areas includes ecosystems that meet the narrow habitat requirements of many of our specialist species, and we’re building like fools in them. Then we feign victimhood and solicit pity when the calamity strikes: fires, floods, landslides, and washouts—again and again. Wouldn’t it be a whole lot smarter to build somewhere else? It may seem like a lot to do for some specialist animals, but it’s not. Because, you see, we should and can live somewhere else—they can’t.

The Allegheny Woodrat (Neotoma magister), a threatened species in Pennsylvania and a critically imperiled species in Maryland, is a habitat specialist requiring the forested rocky slopes, talus-flanked ridgetops, and caves of the Ridge and Valley Province for its nest sites and survival. Isolated populations survived within similar environs in the lower Susquehanna River valley’s Piedmont Province and on South Mountain through at least the first half of the twentieth century, but have since been extirpated. Human encroachment that fragments their habitat and promotes exposure to parasite-hosting mammals including the Raccoon (*Procyon lotor)*, carrier of the Raccoon Roundworm (Baylisascarius procyonis), could prove fatal to remaining populations of this native mammal. (National Park Service image by Rick Olsen)

The American Oystercatcher (Haematopus palliatus) is a specialist species that uses its highly adapted bill to feed on marine invertebrates including mollusks, few of which are actually oysters. Reliant upon tidal ecosystems for its survival, many of the seashore animals that make up this wader’s diet are themselves specialist species. Oystercatchers spend nearly their entire lives in tidal marshes or within the intertidal zone on beaches. They also frequent rocky jetties, particularly during high tide. This individual was photographed near the mouth of Chesapeake Bay in Northhampton County, Virginia, a location that, when the waters of the Atlantic started rising over 10,000 years ago, was the lower Susquehanna valley about 60 miles from the river’s mouth at present-day Norfolk Canyon along the edge of the continental shelf. Get the drift?

December 18, 2024December 19, 2024

Seven Reasons to Visit Middle Creek’s Willow Point Right Now

Here are 7 reasons why you, during the coming week or so, should consider spending some time at Willow Point overlooking the lake at the Pennsylvania Game Commission’s Middle Creek Wildlife Management Area.

REASON NUMBER ONE— Wildlife is at close quarters along the trail leading from the parking lot to Willow Point…

Look carefully and you may see one or more species of woodpeckers in the mature trees. We found this Yellow-bellied Sapsucker in a maple near the trail’s terminus at the Willow Point viewing area.

REASON NUMBER TWO— A variety of waterfowl species are lingering on ice-free sections of the lake surrounding Willow Point…

Noisy flocks of Tundra Swans and Canada Geese on open water at Willow Point.

Mallards — Mallard drakes near the point.

A small flock of Green-winged Teal feeding among the Mallards.

A flock of Northern Shovelers has been frequenting the shallows along the south side of Willow Point for at least two weeks.

Common Mergansers diving for benthic fare.

REASON NUMBER THREE— Bald Eagles are conspicuous, easily seen and heard…

REASON NUMBER FOUR— Northern Harriers have been making close passes over Willow Point as they patrol Middle Creek’s grasslands while hunting voles…

REASON NUMBER FIVE— The annual observance of the White-tailed Deity holidays may be drawing to a close for the gasoline and gunpowder gang, but for the supreme ungulates, the rituals that lead to consummation of their unions are still ongoing…

REASON NUMBER SIX— Sandhill Cranes are still being seen from Willow Point…

REASON NUMBER SEVEN— The crowds that will accompany the arrival of thousands of Snow Geese in early 2025 can make visiting Willow Point a stressful experience. Visit now to see these birds and mammals at Willow Point and you might just have the place all to yourself. Then you can spend your time looking through the flocks of waterfowl and other birds for unusual new arrivals instead of wading through a sea of humanity.

November 12, 2024November 14, 2024

A Visit to Hawk Mountain Sanctuary

Mid-November is our favorite time of year to visit Hawk Mountain Sanctuary on Blue Mountain/Kittatinny Ridge just to the east of the lower Susuquehanna valley near Kempton, Pennsylvania. By now, the huge crowds that come to see October’s world-famous raptor flights and spectacular fall foliage have dwindled to small groups of serious hawkwatchers and hardy trail enthusiasts. Join us as we drop in on the Keystone State’s most famous birding destination.

Hawk Mountain Sanctuary Entrance — The entrance to Hawk Mountain Sanctuary is located at 1700 Hawk Mountain Road off PA Route 895 east of PA Route 61.

Hawk Mountain Sanctuary Headquarters — Start your visit with a stop inside the refuge headquarters building where you’ll find raptor ecology and migration displays, a gift shop, and a window overlooking a busy bird-feeding station. Hawk Mountain is a non-profit organization that receives no taxpayer support and relies largely upon membership fees and donations for the majority of its operating expenses. Inside the headquarters building, you can pay dues and join on the spot.

Native Plant Garden — The native plant habitat includes a pond and a rain garden that collects stormwater from the roof of the headquarters building. There’s also a memorial fern garden named for the refuge’s first curator, Maurice Broun, author of a 1938 index to the ferns of North America.

Trail Sign — After a visit to the habitat garden, it’s time to make our way toward the lookouts.

PA Historical Marker, Hawk Mountain Sanctuary. — 2024 marks the 90th anniversary of the founding of Hawk Mountain Sanctuary. We stopped at the trail crossing along the mountain road to admire this newly erected sign.

Hawk Mounatin Sanctuary Trailhead Gate — Trail fees are collected to support the sanctuary’s operations and maintain its 2,600 acres. Members enter free.

Hawk Mountain Interpretive Kiosk — Interpretive signs and trail information are provided throughout the refuge, particularly along the mile-long climb to the North Lookout.

River of Rocks Trail — Aside from the route to the lookouts (along which sturdy shoes and good balance are a must), many of the sanctuary’s hiking trails require special equipment and preparations. Be certain to follow the posted guidelines.

Raptor education panels along the lookout trail. — The scope of Hawk Mountain’s educational mission includes topics ranging from local Appalachian natural history to global raptor conservation.

Hawk Mountain South Lookout — Just a few hundred yards from the entrance gate, South Lookout provides a panoramic view of the “River of Rocks” talus outcrop and beyond. On days with southerly winds, autumn raptor flights are sometimes enumerated from this location.

Hawk Mountain’s “classroom in the sky”, the North Lookout, hosts school and scout groups learning raptor identification and ecology. It’s the sanctuary’s primary location for counting thousands of migrating birds of prey each fall.

Students quickly learn to identify distant Turkey Vultures by their upturned wings held in a dihedral posture and by their rocking motion in flight.

Hawk Mountain North Lookout — After the pupils depart for the day, there are but few observers remaining to find and count passing hawks and eagles during mid-November.

While sitting quietly among the boulders of North Lookout waiting for the next bird to come along, one can be treated to a visit by one or more of a local population of Southern Red-backed Voles (Clethrionomys gapperi).

While you were busy looking up, the Southern Red-backed Vole was at your feet scarfing up the crumbs from your sandwich. When not availed of our leftovers, its diet includes seeds, various plant parts, and subterranean fungi.

Playful groups of Common Ravens often provide comic relief during interludes in the parade of migrants.

Don’t look now, but your friend the vole has scurried away and a Northern Short-tailed Shrew (Blarina brevicauda) has arrived from beneath the rocks to finish the remnants of your lunch. On the rocky outcrops atop the ridges of southeastern Pennsylvania, these mammals are often found in close company; Red-backed Voles traveling through the burrows and runways created by Northern Short-tailed Shrews instead of excavating their own. Unlike the vegetarian voles, shrews are classified as insectivores, behaving mostly as carnivorous mammals. Equipped with salivary venom, they can consume prey as large as other similarly sized vertebrates, including small voles.

But late-season visitors really want to see a Golden Eagle. On a chilly day with gusty northwest winds, few are disappointed.

Hatch-year/juvenile American Goshawk — We got very lucky during a recent day on North Lookout, spotting this rarity, a hatch-year/juvenile American Goshawk (Accipiter atricapillus), a species which, in 2023, was split from the Northern Goshawk (Accipiter gentilis), a species which was simultaneously assigned the new common name Eurasian Goshawk. Even more recently, within the past several weeks, the genus name Astur has replaced Accipiter for the goshawks, now formally known as the the American Goshawk (Astur atricapillus) and the Eurasian Goshawk (Astur gentilis). The new classification includes Cooper’s Hawk in the genus Astur, while the Sharp-shinned Hawk remains in the genus Accipiter.

If the cold of mid-November doesn’t cramp your style, and if you’d like to seize your best opportunity for a much-coveted sighting of one or more of the late-season specialties, then now is the time to visit Hawk Mountain Sanctuary. Bring a cushion upon which to sit, dress in layers, pack a lunch, and plan to spend the day. You could be rewarded with memorable views of the seldom-encountered species some people spend years of their lives hoping to see.

To learn more, check out the Hawk Mountain Sanctuary website.

October 31, 2024October 31, 2024

Three’s Company

For many species of terrestrial vertebrates living in the lower Susquehanna valley, it’s time to take refuge in a safe place below ground to enter a winter-long slumber. The numerous frosty nights of the past two weeks have expedited the stragglers’ efforts to find a suitable place to pass our coldest months.

Wood Turtles — Aside from the Eastern Box Turtle (Terrapene carolina carolina), the Wood Turtle (Glyptemys insculpta) is our most terrestrial species of testudine, however it is seldom found far from wet bottomlands. Last week, we found this pair preparing to burrow into alluvial soils along the edge of a floodplain wetland where they will spend the winter. In recent years, Wood Turtle numbers have plummeted due to habitat fragmentation and loss, and due to collecting by short-sighted petkeepers and profiteers.

A sluggish Wood Turtle catching a few last rays of sunshine before digging in for the winter. If you encounter these or any turtles now or at any time of year, it’s important that they not be disturbed. Look and leave them be.

And now, just in time for Halloween, a look at some hibernating species that some of our more squeamish readers consider to be “scary”.

In the mountainous forests of the Ridge and Valley Province, there lives a seldom seen little mouse which, unlike the more familiar species found in the fields, farms, and homes of our valleys and Piedmont, spends almost half the year in true hibernation.

The Woodland Jumping Mouse (Napaeozapus insignis) is a nocturnal species of rodent found primarily on rocky forest slopes, particularly those with growths of Eastern White Pine and Eastern Hemlock. Unlike the similar White-footed Mouse, a species that sometimes enters homes in the fall and remains active year-round, the Woodland Jumping Mouse builds a small subterranean nest among rocks and boulders where it will enter a long winter slumber, often not emerging until the milder days of April. During the long hibernation, these mice sometimes fatally diminish the energy stored in their body fat; up to 75% may perish before spring arrives (Merritt, 1987).

In spring and fall, Eastern (Black) Ratsnakes are frequently seen basking in the sun as they absorb heat and get their metabolism going. During the hottest days of summer, when ambient air temperature is sufficient for their needs, they become nocturnal, hunting mice and other creatures that are also active at night. During October, they make their way back to a winter den where they will remain until March or April.

Eastern Ratsnake — A last-minute Eastern (Black) Ratsnake makes a slow late-October trek across a mountain road toward a winter den on the south slope of the ridge.

That’s right, all three of these snakes are known to cohabitate, not just during hibernation, but at other times of the year as well. And you thought they were mean and nasty to anything and everything in their path, didn’t you?

Here in the northeastern United States, fear of indigenous wild snakes is a totally irrational anxiety. It’s a figment of our indoctrination. Their wicked reputation is almost exclusively the result of a never-ending stream of demonizing propaganda from the pulpit, press, parents, panicked, and picture shows. All they want from you and I is to be left alone. Want something to really be afraid of this Halloween? Try domestic dogs. That’s right—the “friendly” pooch. In the United States, they’ll land hundreds of people in the emergency room today. Don’t like that one. How ’bout cars and trucks. They’ll kill and maim people all day long. And don’t forget about sugar. Yes friends, that sweet treat is pure poison that kills all day long. Happy Halloween!

SOURCES

Merritt, Joseph F. 1987. Guide to the Mammals of Pennsylvania. University of Pittsburgh Press. Pittsburgh, PA. pp.230-233.

Shaffer, Larry L. 1991. Pennsylvania Amphibians and Reptiles. Pennsylvania Fish Commission. Harrisburg, PA.

September 27, 2022

Photo of the Day

Mammals of the Lower Susquehanna River Watershed: A White-footed Mouse Peers from its Nest — Uncle Tyler Dyer reminds all his vegetarian friends to speak clearly when ordering the “House Salad” in a noisy restaurant, otherwise you may go hungry. Unlike Uncle Ty, the White-footed Mouse (Peromyscus leucopus), seen here in its nest, is omnivorous, so it seldom goes hungry.

Category: Mice and Voles (Cricetidae)