Some comparative attributes of unspoiled lotic vs. lentic freshwater ecosystems. Low-gradient (slow-moving) lotic waters often create, and remain connected to, accompanying riverine wetlands (a lentic freshwater ecosystem). These swamps, marshes, and ditches absorb, purify, and infiltrate flood waters while supporting a diverse number of plant and animal species.
We frequently perceive all waterfowl migration to be synchronized with the conspicuous movements of familiar species like Snow Geese, Tundra Swans, and Canada Geese—big flights coming south in October and November, then a return to the north in late February and March. And we’re all quite aware of the occurrence of large gatherings of some of these migrants while they make stopovers on some of our largest lentic (still) waters—the man-made lakes and reservoirs created by damming local streams. But did you know that there are populations of colorful waterfowl with dynamic migrations that extend throughout the winter and early spring with movements that are often continuous. Under favorable conditions, these birds favor the lotic (flowing) waters of the river and its larger tributaries as they transit the lower Susquehanna valley. That’s because unpolluted lotic freshwater ecosystems support a greater diversity of plants and animals than lentic waters, and therefore offer more opportunities for hungry migrating waterfowl to find food. Let’s have a look at some of the species that visit the river during their seasonal journeys…
While the urge to head south in the autumn is largely stimulated by the shortening of the photoperiod, it is the presence of ice, particularly on glacial lakes throughout the lands to the north of the lower Susquehanna River basin, that pushes many diving ducks to finally make their way south toward the guarantee of open-water feeding areas along the coast. This movement may occur at anytime between November and late February or, as we have seen during some of the mild winters of recent decades, it may scarcely be noticed at all.Common Mergansers often lead they way when it comes to migratory diving ducks. They regularly move south in conspicuous numbers by late November and December and are regularly pushing north as soon as the ice begins to melt. During a typical year, it is not unusual for some populations of these large diving birds to remain north of us during the winter. Then, in the days after a sudden rush of frigid polar air, an appreciable increase in ice cover will force a mid-winter movement of birds down the Susquehanna.Temperatures in lotic fresh waters vary over the length of the stream or river. They are largely determined by the collective impact of the numerous sources of heat flux depicted in this graphic. (Environmental Protection Agency image)Buffleheads begin passing through the lower Susquehanna region in Novemeber on their way to coastal saltwater bays for the winter. Lingering populations feed by diving in the river’s pools and riffles for benthic invertebrates including snails and insect larvae. Lesser quantities of aquatic plant matter supplement their diet.Many Common Goldeneyes will remain on shallow, ice-free waters of the northern lakes and rivers sculpted by the most recent glacial event, but only until they are forced south into and through the lower Susquehanna valley by the encroachment of freezing conditions. On the river, they are among the dozen or so species of diving ducks we see visiting or passing through during the typical late fall and early river.
During their visits to the lotic (also known as riverine) fresh waters of the Susquehanna and its largest tributaries, benthic-feeding waterfowl make short dives to take advantage of the plants, small fish, invertebrates, and other food sources inhabiting the stream bottom in the riffles and pools of the free-flowing waterway. Substrates, listed here by size (in descending order), along with other parameters influenced by this zonation determine the variety and abundance of the forage available to migrating waterfowl and other consumers. Ice or high water and poor visibility due to flooding can render the riffles and pools of the channel unusable for feeding. The birds must then choose to either linger and rest without feeding or leave the lotic freshwater habitat to seek sustenance. During a flood, this may require relocation to a nearby lentic (still) body of fresh water such as a lake or reservoir. The presence of ice will almost invariably force the birds to fly on to the Atlantic Coastal Plain and the tidal waters of its bays and estuaries.Hooded Mergansers are one of the few species of diving ducks likely to utilize flooded shoreline timber and riverine (fluvial) wetlands as refuge from high water on Susquehanna.A Pied-billed Grebe and a pair of Canvasbacks on an ice-free stretch of the lower Susquehanna in mid-winter feed and loaf in a riffle-flanked pool where a large mat of American Eelgrass, a submerged aquatic plant also known as Tapegrass or Wild Celery, grows during the summer. The vast mosaic of riffles and pools in a river this size offers tremendous opportunities for a diverse array of aquatic species to find their niche wherein they can survive and flourish.The presence of ice forces Buffleheads and other diving ducks to gather in turbulent open water, often below a riffle or dam. Another alternative is to continue on toward the salty bays and estuaries of the coast. High water may push these birds into the shallows among the flooded woods to feed, but they seldom utilize heavily forested riparian wetlands as a refuge due to their need for a running start to get airborne.
Riffle and Pool Characteristics of High Gradient (A) and Low Gradient (B) Streams. This graphic illustrates the change in deposition characteristics of a stream or river as its gradient decreases. A high-gradient stream (A) has a rapid velocity, often forms falls, and tends to carry away a high volume of all but the largest of particles of potential substrates as they erode from the surrounding landscape. On a low-gradient stream, the loss in water velocity reduces the water column’s ability to transport even the smallest of substrate particles. Deposition of this gravel, sand, silt, and clay forms lateral bars that over time create the familiar meandering path of a naturally flowing lowland stream. (National Park Service image)Benthic substrates in lotic freshwater pools and riffles support an abundance of life forms ranging from colorful diatoms on rocks and cobble, to invertebrates including snails and insect larvae, to fishes like this young Channel Catfish. Free of accumulations of sediment, this river bottom not only provides habitat for a healthy fishery, it facilitates the bidirectional exchange of water between the Susquehanna and its underlying aquifer.On the lower Susquehanna, populations of young Quillback suckers are found almost exclusively in clear, high-gradient pools.The Harlequin Duck winters along the rocky shores and man-made jetties of the Atlantic coast. In summer, they nest on fast-moving, headwater streams well to our north. Very rare on the Susquehanna, this is the first of two individuals found during March and April of 2025. It was observed feeding in the swift waters of the high-gradient riffles and pools where the river cuts through Blue Mountain north of Harrisburg. During previous weeks, Harlequin Ducks were being seen along the coast as far south as the mouth of the Chesapeake at Cape Charles, Virginia. It’s very possible that some of these birds traveled north through the bay area and up the Susquehanna on their way north.
Fluvial Geomorphology of a Stream. Many of the Susquehanna’s tributaries pass through each of these three erosional zones. Along the way, they carry out the process of breaking down the mountains formed by the Allegheny orogeny, the collision of North America and Africa that created the supercontinent Pangea about 325 to 260 million years ago (during portions of both the Carboniferous and Permian periods). Today’s main stem of the lower Susquehanna passes through a transfer zone (Zone 2), carrying eroded materials to a depositional zone (Zone 3) located within the ancient Susquehanna canyon stretching from Havre de Grace, Maryland, to Norfolk Canyon on the edge of the continental shelf. Within this zone, more than a 10,000-year accumulation of post-glacial sediments lies submerged by the rising waters of the Atlantic Ocean and Chesapeake Bay. Although the present-day lower Susquehanna is largely a transfer zone, some deposition occurs along low-gradient segments of the river, particularly where its course parallels the watershed’s ridges both above and below the high-gradient rapids where its path has eroded passage through the highlands. (National Park Service image)Although the present-day lower Susquehanna is largely a transfer zone, some deposition occurs along low-gradient segments of the river, particularly where its course parallels the watershed’s ridges both above and below the high-gradient rapids where its path continues to erode passage through the bedrock. On this 1908 map of the Susquehanna at Conewago Falls, alluvial terraces of gravel, sand, silt, and clay can readily been seen as pale areas nearly lacking brown contour lines along the shorelines and islands of the river. Deposits within most of these terraces date back to the melt period following the most recent glacial event and beyond. The delta shown at the mouth of Conewago Creek (west) includes massive volumes of material deposited by both the creek and the river. This delta is currently known as Brunner Island, much of it developed as the site of a coal/gas-fired electric generating station. Terrace deposits along the Susquehanna’s shorelines created extensive perched marshes and swamps (wooded marshes) fed by rains, high river water, small streams, and springs, the latter often seeping from the base of the rocky escarpments carved by the ancient Susquehanna and defining the present-day inland border of the floodplain. We call these sites “Alluvial Terrace Wetlands”. Few of these critical components of river morphology survive. Those not drained for farmland were obliterated by urbanization and canal, railroad, and highway construction. (United States Geological Survey base image: Middletown, PA, quadrangle, 1908)Water Willow is a familiar emergent plant that colonizes lateral bars and other alluvial deposits in low-gradient segments of the Susquehanna.The fine roots of Water Willow collect sediment and absorb nutrients while creating dense cover for young fish and numerous species of invertebrates including the Virginian River Horn Snails seen here.
Prior to the nineteenth century, the low-gradient flow regime of the river both above and below the riffles at Chiques Rock (lower right on map) created prime wildlife habitat. The natural accumulations of nutrients and substrates carried into and through the lotic waterway’s pools and riffles were cycled into an ideal growing medium for extensive mats of American Eelgrass and other aquatic plants. This underwater forest hosted a seemingly endless abundance of invertebrates and fishes (both resident and migratory)—supporting a variety of consumer species including various populations of humans. But soon after the mass clearing of much of the watershed’s land for farming and lumber, the mill ponds created by dams constructed on streams to power saw and grain mills became brimful with sediments eroded from the unprotected ground. During storm events, torrents of these sediments then flowed full bore toward the Susquehanna, and began accumulating in the low-gradient segments of the river.
Sediments left behind after the removal of mill dams are known as legacy sediments. They disconnect the stream from its historic floodplain and riverine (fluvial) wetlands, thus intensifying the impact of high water in the surrounding landscape. As these nutrient-charged deposits wash away, they become a source of pollution in the waters of the Susquehanna and Chesapeake.A mat of American Eelgrass growing in the flowing waters of the Susquehanna below Conewago Falls. Eelgrass and other submerged aquatic plants provide essential habitat for a wide variety of small fish and invertebrates while also consuming nutrients deposited in the cobble, gravel, and sand substrate of the river’s pools. Excess quantities of smaller particles of silt and clay can clog the substrate and thus inhibit the hyporheic exchange of water between the stream channel and the underlying aquifer, often diminishing the biomass and diversity of organisms inhabiting this benthic habitat. Buried in these life-choking sediments, the river bottom becomes inhospitable to growth of submerged aquatics including eelgrass.This low-gradient stretch of the Susquehanna at Marietta flows parallel to the Chickies Quartzite “Hellam Hills” before making a sharp right turn to punch through the ridge as a series of rapids at Chiques Rock. Formerly a fully functional lotic ecosystem and a paradise for migrating waterfowl, this river segment is now impaired by accumulations of nutrient-laden sediments from agricultural and urban runoff.Nutrient and sediment-loaded flood waters roar across the diabase boulders at the York Haven Dam and Conewago Falls, a high-gradient segment of the Susquehanna.They continue past Brunner Island (left power plant stacks) and through Haldeman Riffles and the Shocks Mills Railroad Bridge……into the stretch of river known as the “Marietta broads” along the base of the Chickies Quartzite “Hellam Hills”. The low stream gradient here produces a slower current and increased deposition of sediments.As the flood surges through the riffle and pool complex at Chiques Rock, the high stream gradient maintains a velocity in the water column sufficient to keep additional sediments in suspension until they reach the low-gradient river segment just downstream at Washington Boro, site of a naturally occurring lateral bar area known as the Conejohela Flats. These bars now lie within the man-made depositional zone known as “Lake Clarke”. Created nearly a century ago by construction of the Safe Harbor Dam, this impoundment is accumulating astounding volumes of nutrient-loaded sediments that continue to encapsulate the flats within a stream-impairing delta.Anytime from November to April on the lower Susquehanna, a group of Redheads, Canvasbacks (3 birds to right of the middle of the picture), and a Horned Grebe (lower left) is a welcome sight in a riverine pool known to have a summertime growth of American Eelgrass. Noted Dr. Herbert Beck in 1924 when describing the Canvasback, “Like all ducks, …, it stops to feed within the county (Lancaster) less frequently than formerly, principally because the vast beds of wild celery which existed earlier on broads of the Susquehanna, as at Marietta and Washington Borough, have now been almost entirely wiped out by sedimentation of culm. Prior to 1875 the four or five square miles of quiet water off Marietta were often as abundantly spread with wild fowl as the Susquehanna Flats are now. Sometimes there were as many as 500,000 ducks of various kinds on the Marietta broad at one time.”Today, seeing just dozens of Aythya genus ducks (Redheads, Canvasbacks, scaup) on the lower Susquehanna is a notable event. If they happen to be forced down by inclement weather while migrating through, you might get lucky enough to see several hundred.While the recovery of eelgrass/wild celery beds on the Susquehanna is trivial in scale and offers little support for numbers of waterfowl to return to historic levels, restorations on the upper Chesapeake in the vicinity of the Susquehanna Flats between Havre de Grace and Aberdeen Proving Grounds may have helped refuel a gathering of mostly Aythya genus ducks during the final days of February. This mass of ducks, many of which were forced south from the frozen Great Lakes during the previous weeks (some by way of the ice-choked Susquehanna) were apparently making an abrupt turn to make their way back north. Their stay was brief, but estimates by local birders put their numbers as high as one half million. The vast majority of the concentration consisted of Aythya species: Redheads, Canvasbacks, Ring-necked Ducks, and both Lesser and Greater Scaup. It probably included a mix of birds including both northbound migrants from further down the coast and the aforementioned refugees that had just arrived to pay a quick visit while escaping the late-season ice before turning around.During the past two centuries, as food supplies in the Susquehanna grew increasingly compromised for benthic feeders like these Lesser Scaup and other diving ducks, a change in distribution was necessary for survival.As individual species, Lesser Scaup and other waterfowl that fail to adapt to natural or man-made changes in their habitats and food supplies may see their overall global numbers falter.
Despite being located in the transfer zone, the lower Susquehanna has become a significant depositional zone along much of its length, mostly courtesy of the placement of sediment-trapping man-made dams.
Following construction of the mill dams and ponds on nearly every mile of the lower Susquehanna’s low-gradient tributary streams, enterprising parties moved on to the river. The first significant spans were constructed using wide timber cribs filled with large rock. They were placed to create water deep enough to allow canal boats to cross the Susquehanna at both Clark’s Ferry at the mouth of the Juniata River in Dauphin County and at Columbia/Wrightsville. These dams also diverted water into the newly excavated canals—the Pennsylvania Eastern Division Canal (completed in 1833) which followed the river’s east shore from Clark’s Ferry to Columbia, and the Susquehanna and Tidewater Canal (completed in 1840) along the west shore from Wrightsville to Havre de Grace, Maryland. Placement of these sediment-trapping man-made dams began a process of converting vast mileage of the lower Susquehanna from a transfer zone into a deposition zone. In addition, layout of the canals and locks followed the contours along the base of the riverside ridges, seriously altering most of the alluvial terrace wetlands that the river had created as a feature of its floodplain during the post-glacial period.
Construction of the canal dams was just the beginning. During the twentieth century, more massive dams would be added to the main stem of the river for hydroelectric energy production at York Haven, Safe Harbor, Holtwood, and Conowingo. Upon their completion, the days of unassisted anadromous fish migrations were over. On both the river and its tributaries, smaller dams including dangerous low-head dams maintain water levels for boating and recreation. They too create current-diminishing, pseudo-lentic waters that blanket the lotic riffle and pool substrates with polluted sediments.
MAN-MADE DAMS TURN LOTIC WATERS INTO UNFLUSHED TOILETS
The construction of dams on the lower Susquehanna has converted vast mileage of the river from a lotic freshwater system into a series of man-made lentic freshwater lakes. These areas have lost their function as a lotic transfer zone and are now a sort of dysfunctional series of depositional zones collecting vast volumes of sediment containing nutrients and other pollutants. Within each impoundment, the reduced velocity of the river causes it to drop suspended sand first, then the finer particles of silt and clay closer to the dam. The flow regime of riffles and pools is lost and the hyporheic zone that exchanges water between the river and the underlying aquifer is clogged. These impaired segments of river become ripe for eutrophication: algal blooms followed by die offs that can lead to a fatal reduction of dissolved oxygen in the water column.Deposits of lateral bars of sediment in low-gradient segments of the Susquehanna can create shallow water feeding habitat for puddle/dabbling ducks like these Gadwall. Where sediment pollution is severe, benthic foods in these areas often consist mostly of invertebrates and plant matter deposited by the current, the buried substrates devoid of a functioning ecosystem and the waters subject to eutrophication.Common Goldeneyes on a patch of open water on an otherwise ice-covered “Lake Clarke”, the impoundment created by Safe Harbor Dam. While they may find this spot advantageous for loafing, the food supply over the sediment-buried substrate will be limited.By the end of the twentieth century, accumulations of polluted sediments behind lower Susquehanna dams were nearing capacity. There is no working plan to attenuate the massive release of these pollutants that may be triggered by a catastrophic flood. The effort to reduce nutrient and sediment runoff remains the focus so that new loading is kept to a minimum and won’t add to the capacity problems at the dams or continue downriver to the Chesapeake at full strength when the dams are full. Alleviating the sediment aggregation problem within the river’s impoundments is a tall order and a dilemma not easily solved. (United States Geological Survey image)Common Mergansers will feed where benthic substrate supports the small fish and invertebrates they prefer. They will, however, gather in extraordinary numbers on the “lakes” created by riverine dams. Though they can only feed on what floats in with the current, hundreds or sometimes thousands of Common Mergansers will concentrate on “Conowingo Pond” during the late fall or early winter. There, safety in numbers gives them some guarantee of protection against the multitudes of eagles that simultaneously frequent the vicinity. Another advantage of staging on “Conowingo Pond” is its close proximity to favorable feeding areas on upper Chesapeake Bay and stretches of the Susquehanna where lotic riffles and pools offer abundant opportunities below the river’s dams.Fortunately for everything else living in the benthos, Common Mergansers are big enough to devour invasive, non-native Rusty Crayfish when they find them in our lotic waterways.
TIME TO CLEAN UP OUR ACT
WHERE DOES YOUR STORMWATER GO?
Channelized Urban/Suburban Streams Function as Sewers. They have no attached lowlands or floodplains to absorb, purify, and infiltrate runoff from rain events. Pollutants including litter, pet waste, lawn chemicals, tire-wear particles, hazardous fluids, and sometimes untreated human excrement flush unchecked from the municipal storm drainage system into the waterway. Thermal shock from summer downpours washing across sun-heated pavements can kill temperature sensitive fishes and other aquatic life. Nutrient and sediment loads from these impaired tributaries later accumulate downstream in low-gradient segments of the Susquehanna, turning the river into an open-air cesspool. Aggressively working to implement projects that eliminate these sources of pollution are the only effective way to keep the problem from getting worse. Making things better requires a lot more dedication and effort. (United States Geological Survey image by Frank Ippolito)
RIPARIAN BUFFERS MAKE A DIFFERENCE…WIDER IS BETTER
To sequester sediment and cycle nutrients (primarily nitrogen and phosphorus) contained in farm runoff, the U.S.D.A. recommends installing riparian buffers between streams and lands used for grazing and raising crops. To protect pollinating species including bees and butterflies from pesticide drift and eroding soils rich in fertilizers, they further recommend installing a stand of wind-pollinating plants such as conifers, oaks, and birches between the field and streamside plantings. These same conservation practices improve water quality and wildlife habitat on waterways located in residential and commercial areas as well. (United States Department of Agriculture image, click to enlarge)
FLOODPLAIN RESTORATION
Regardless OF HOW LONG YOU’VE BEEN CONDITIONED TO THINK OTHERWISE, THIS IS A DYSFUNCTIONAL, POLLUTED CREEK—AND IT NEEDS HELP
A channelized low-gradient stream eroding a path through deposits of legacy sediments displaces flood waters into previously unaffected areas and provides a continuing source of nutrient and sediment pollution during storm events. These impaired waters have a diminished capacity for supporting aquatic life including fishes.
RESTORED TO ITS HISTORIC FUNCTIONS
On an adjacent segment of the same creek, this legacy sediment removal project restored a braided meandering channel and connected it to its newly liberated, historic floodplain. In just their second year, the fluvial wetlands are effectively absorbing stormwater and sequestering nutrients as an attached component of the stream’s riffle and pool complex. During our visit earlier this week, we found American Toads, Northern Leopard Frogs (Lithobates pipiens), and Northern Spring Peepers breeding here. It’s just as Castor canadensis would have it!
“STOP HEMMING AND HAWING AROUND ALREADY”
“HEY COWBOY, HOW ‘BOUT GETTIN’ THEM FILTHY LITTLE DOGIES OUTTA DAT CRICK?”
Here’s a polluted stream in a pasture with grazing livestock. The site is a former mill pond within which the creek eroded a channel following removal of the dam. The animals defecate and urinate where access to water is gained at a broken down embankment of the nutrient-loaded legacy sediments deposited in the pond more than a century ago. It’s a haphazard form of animal husbandry and a reminder that all it takes is just one stubborn jackass to foul up the whole waterway.
DIRECT SOURCES OF NITROGEN (AMMONIA) POLLUTION IN STREAMS
DID YOU KNOW that a dairy cow produces about 80 pounds of waste (excrement and urine) every day?
DID YOU KNOW that a horse produces about 50 pounds of waste (excrement and urine) every day?
DID YOU KNOW that a human produces about 3 to 4 pounds of waste (excrement and urine) every day? The exceptions, of course, are those who continue to insist that raising farm animals in and alongside a body of water is okey-doke—a harmless practice. These individuals tend to retain the former constituent of human waste and are thus full of it.
“ATTABOY TEX, THAT’S MORE LIKE IT!”
Now that’s better. Legacy sediments have been removed to reconnect the stream to its floodplain. A livestock crossing and exclusion fencing has been installed, and a nutrient-consuming riparian buffer has been planted. This creek segment’s pollution woes have been mitigated. Do you have a neighbor needing this type of remedial work on their farm? Have them call your local conservation district office for advice. Some programs include financial assistance covering the costs of installation as well as monetary incentives for helping to clean up the water.
AND FINALLY
WHEN IT COMES TO BUILDING DAMS ON LOTIC FRESH WATERS…
…LEAVE IT TO THE BEAVERS
North American Beavers (Castor canadensis) create habitats that connect the riffle and pool regime of a low-gradient stream to a surrounding fluvial wetland that retains sediments, cycles nutrients, and provides essential habitat for hundreds of plant and animal species. Floodplains are for flooding. And if a beaver floods an area, you can be guaranteed that it was already part of a floodplain. You see, beavers don’t encroach upon humans, it’s humans doing the encroaching upon beavers. (National Park Service image)
MAD HATTERS
DID YOU KNOW that even before the landscape was cleared for farms and a supply of timber, and before mill dams on local creeks began accumulating soil runoff from the consequently barren hillsides, all the North American Beavers, the keystone species of lower Susquehanna stream ecology, were killed and sold to make hats? It’s no wonder things are fubar!
COMING SOON…
Horned Grebes are regular migrants and sometimes winter residents on ice-free stretches of the lower Susquehanna. They spend their time plying the benthic substrate of the river’s clear riffles and pools for a variety of invertebrates and small fish. Look for them moving north in coming days sporting this beautiful breeding plumage.April and early May are prime time for observing Common Loons on the Susquehanna as they undertake a journey from the Atlantic surf where they spent the winter to nesting sites on northern lakes. For this migrant in breeding plumage, clear water for sighting plenty of benthic life in the river’s riffles and pools assures a successful dive in search of energy-replenishing forage.
The first day of winter is the darkest day of the year. In the midst of the cold weather that accompanies it, one hardly thinks of looking for insect activity. But in subterranean environs where the temperature remains relatively constant, life goes on. We recently discovered this handsome Camel Cricket while performing some maintenance in our below-grade utility entrance. Worldwide in distribution, Camel Crickets, also known as Cave Crickets, Sand Treaders, and Spider Crickets, include hundreds of species in the family Rhaphidophoridae. Most are omnivorous residents of caves, mines, cellars, hollow logs, wood piles, wells, and other dark, temperature-stable situations where they feel their way around with their antennae while searching for food. Camel Crickets usually escape notice, keeping only nocturnal hours when venturing out from light-deprived cover and lacking the organs to produce the familiar “chirps” that call attention to other crickets during the breeding season.
Among the last of the dragonflies to still be flying during late November is the Autumn Meadowhawk (Sympetrum vicinum). Earlier today, we photographed this specimen as it basked in warm sunshine at Wildwood Lake in Harrisburg. Elsewhere in the Lower Susquehanna River Watershed, look for Autumn Meadowhawks near lakes and ponds located within or near woodlands and forest.
During these last mild evenings of fall, the trilling call of the Narrow-winged Tree Cricket (Oecanthus niveus) can still be heard among the withering growth of thickets, fields, and forest edges. As the temperatures plummet, the pulsating rate of this insect’s song slows proportionally. Below about 40 degrees Fahrenheit, there is silence.
As we begin the second half of October, frosty nights have put an end to choruses of annual cicadas in the lower Susquehanna valley. Though they are gone for yet another year, they are not forgotten. Here’s an update on one of our special finds in 2025.
During late June of 1863, the beginning of the third summer of the American Civil War, there was great consternation among the populous of the lower Susquehanna region. Hoping to bring about Union capitulation and an end to the conflict, General Robert E. Lee and his 70,000-man Army of Northern Virginia were marching north into the passes and valleys on the west side of the river. The uncontested Confederate advances posed an immediate threat to Pennsylvania’s capital in Harrisburg and cities to the east. Marching north in pursuit of Lee was the First Corps of the Army of the Potomac, the lead element of the 100,000-man Union force under the direction of newly appointed commander General George G. Meade.
Upon belatedly learning of Meade’s pursuit, Lee hastily ordered the widely separated corps of his army to concentrate on the crossroads town of Gettysburg. As the southern army’s Third Corps under General A. P. Hill approached Gettysburg from the west, they were met by Union cavalry under the leadership of General John Buford. Dismounted and formed up south to north across the Chambersburg Pike, Buford’s men held off Confederate infantry until relieved by the arrival of the Union First Corps. As he deployed his men, the First Corps’ commander, General John F. Reynolds of Lancaster, was struck by a bullet and killed.
During the first day’s fighting at Gettysburg on July 1, 1863, the northernmost position in the Union First Corps’ line was held by its Second Division commanded by General John C. Robinson. His men would defend their right flank against attacks from Confederate General Richard S. Ewell’s Second Corps as they arrived from the north to face off against the Union Eleventh Corps which had arrived to take positions north of the town. During the afternoon, upon becoming outnumbered and overwhelmed, the Union forces would retreat south through the town to take up positions on Cemetery Hill by nightfall. Deployments extending south and east of Cemetery Hill would ultimately prove victorious for Union forces during the battle’s final day on July 3.John C. Robinson’s Second Division “invaded” Pennsylvania as one of Meade’s lead elements charged with intercepting Lee’s Confederate Army. (National Park Service image)
If you visit the Gettysburg battlefield, you can find the General John C. Robinson monument at the site of his division’s first-day position along Doubleday Avenue at Robinson Avenue near the Eternal Light Peace Memorial. But that’s not the Robinson we went to Gettysburg to see.
Following up on our sight and mostly sound experiences with some Robinson’s Cicadas, an annual species of singing insect we found thriving at Gifford Pinchot State Park in York County, Pennsylvania, during late July, we spent some time searching out other locations where this native invader from the southern United States could be occurring in the Lower Susquehanna River Watershed.
During mid-August, we stumbled upon a population of Robinson’s Cicadas east of the Susquehanna in the Conewago Creek (east) watershed in Londonderry Township, Dauphin County, and made some sound recordings.
After pondering this latest discovery, we decided to investigate places with habitat characteristics similar to those at both the new Londonderry Township and the earlier Gifford Pinchot State Park locations—successional growth with extensive stands of Eastern Red Cedar on the Piedmont’s Triassic Gettysburg Formation “redbeds”. We headed south towards known populations of Robinson’s Cicadas in Virginia and Maryland to look for suitable sites within Pennsylvania that might bridge the range gap.
Our search was a rapid success. On State Game Lands 249 in the Conewago Creek (west) watershed in Adams County, we found Robinson’s Cicadas to be widespread.
Eastern Red Cedar, a probable host tree for Robinson’s Cicada nymphs, among successional growth on State Game Lands 249. Cedar thickets often become established on shallow or depleted soils on lands originally cleared for farming. They provide excellent cover as well as much needed breeding and feeding areas for birds, mammals, insects, and other wildlife.A male Robinson’s Cicada singing at State Game Lands 249 in Adams County, Pennsylvania.
Following our hunch that these lower Susquehanna Robinson’s Cicadas extended their range north through the cedar thickets of the Gettysburg Basin as opposed to hopping the Appalachians from a population reported to inhabit southwest Pennsylvania, we made our way to the battlefield and surrounding lands. We found Robinson’s Cicadas to be quite common and widespread in these areas, even occurring in the town of Gettysburg itself.
Populations of Robinson’s Cicadas (red) in the lower Susquehanna valley and adjacent areas of the Potomac watershed near Gettysburg. The Triassic Gettysburg Basin is shown in white with intrusions of igneous Triassic-Jurassic diabase in dark green. (United States Geological Survey base image)Robinson’s Cicadas are common on much of the Gettysburg National Military Park property, particularly in the southern reaches where outlying areas are dense with Eastern Red Cedar growth to within several miles of the Mason-Dixon Line. In these tall walnuts and cedars along Confederate Avenue (that’s Little Round Top and its diabase boulders in the background) we recorded the following sound clip of a singing male.Robinson’s Cicada probably extended its range into the lower Susquehanna valley in much the same way General John C. Robinson and the rest of the Army of the Potomac marched into Pennsylvania to meet Lee’s Confederates, by following the terrain of the Triassic Gettysburg Basin. Got a big stand of cedars near you? Be sure to have a listen for Robinson’s Cicadas next summer! (United States Geological Survey base image)
Having emerged from the soil overnight, this pale-colored teneral (soft-bodied) Eastern Scissor Grinder has shed its exuvia (left) and is currently pumping blood throughout its extremities to expand its size and unfurl its wings. During the remainder of the morning, the wings and exoskeleton will darken in color and harden in preparation for flight. As an adult, this cicada then has just weeks to complete its courtship and breeding cycle before facing inevitable doom. To see images and listen to sound clips of this and other annual species, visit our cicada page by clicking the “Cicadas” tab at the top of this page.
Just as we were very pleased last month to have the opportunity to hear the sounds of the rarest of the Periodical Cicadas—the Little Seventeen-year Cicada—in the Conewago Hills of York County to thus provide our only record of the species during the Brood XIV emergence in the Lower Susquehanna River Watershed, we were this week delighted to find and record a population of what may be the valley’s rarest cicada experiencing annual flights—the Robinson’s Cicada—just a few miles away at Gifford Pinchot State Park.
Like the Little Seventeen-year Cicada, Robinson’s Cicada (Neotibicen robinsonianus) is a species found more commonly in the southern United States, occurring with scattered distribution in a range that extends west into Missouri, Kansas, and Texas. They are of rare occurrence in the lands of the Chesapeake drainage basin in Virginia and Maryland.
Populations of Swamp Cicadas, also known as Morning Cicadas, are presently in the midst of their yearly courtship rituals. Their songs are easily heard in woods, edge habitat, and suburbia throughout the region during the AM hours. It was while recording the sounds of these common insects in the Conewago Day-use Area at Gifford Pinchot State Park that we noticed a very unique song from high in the oaks, hickories, and other hardwoods along the lake. Listen to this sound clip featuring a group of serenading male Swamp Cicadas. In the background, a Robinson’s Cicada’s song consisting of a pulsing series of raspy buzzes, each about one second in duration, can be heard, particularly starting at 00:40.Dozen’s of Robinson’s Cicadas were heard this week in the large trees of the lakeside picnic grove in the Conewago Day-use Area at Gifford Pinchot State Park. They remained high in the canopy and were glimpsed only when flying to a new perch, so we’ll have to settle for a photo of an individual from the more southerly portions of the species’ range (provided courtesy of AmaryllisGardener, under license: CC BY-SA 4.0). We recorded these two sound clips of males singing in the forested area west of the picnic grove. The first was nearer the park campground. The second was in the vicinity of the nature center building and includes a Wood Thrush and another Robinson’s Cicada in the background.
The Lower Susquehanna River Watershed, and Gifford Pinchot State Park in particular, may currently represent the northern limit of the geographic range of the Robinson’s Cicada. If you’re in the area during the coming weeks, drop by the park and have a listen. And don’t forget to check out our “Cicadas” page for sound clips of all the species found in our area.
It begins on a sunny morning in spring each year, just as the ground temperature reaches sixty degrees or more…
Eastern Subterranean Termites emerge in unison from a nest located in the soil beneath a log. Each of these swarming “alates” is a potential king or queen seeking to find a location with an ample supply of fallen timber to provide food for establishment of a new colony. They are escorted to the surface by a soldier (lower center) equipped with powerful jaws for protecting the existing nest. Similar-looking worker termites tend the nest, the queen, her eggs, and their siblings, but usually remain hidden from view. The workers feed upon wood, hosting cellulose-digesting protozoa and bacteria in their guts to break down the fibers. This symbiotic relationship is an important mode of decomposition in the forest, the process that turns wood into the organic matter that enriches soil and helps it to retain more moisture.Termites are among the numerous arthropods that join fungi and a variety of microbes to decompose dead wood and other plant matter into the nutrients and organic materials used by living plants to thrive and grow.Within moments of emerging, swarming “alates” ascend a tree trunk or other vertical surface from which they can take flight.Eastern Subterranean Termite “alates” gather atop a stump before launching skyward.Termites swarm in massive numbers in an attempt to overwhelm the predators that are inevitably attracted to their sudden appearance. The few “alates” that survive to find a source of rotting wood in which to begin a new colony are the only hope for continuing their king and queen’s legacy.Soon after lift off, the majority of swarming termites are consumed by swallows, swifts, and other birds, but some are discovered at ground level.A lightning-fast strike with its tongue and this Green frog has snatched up yet another termite. Those that slip by the dragnet of terrestrial and aerial predators can sometimes start a new colony in the ground beneath a dead tree or in a vulnerable house or other wooden structure. To keep a small clan from invading your home, be certain the wood elements of your building(s) are kept dry and are not in contact with dirt, soil, bark mulch, etc. Regular inspections for evidence of their presence can head off the long-term damage termites can inflict on the stuff we construct with tree skeletons.A Green Frog wearing its breakfast. Its next chance for a termite feast may come during the autumn when the Drywood Termites (Kalotermitidae) swarm.
Of course, termites aren’t the only groups of insects to swarm. As heated runoff from slow-moving thundershowers has increased stream temperatures during the past couple of weeks, there have occurred a number of seasonal mayfly “hatches” on the Susquehanna and its tributaries. These “hatches” are actually the nuptial flights of newly emerged imago and adult mayflies. The most conspicuous of these is the Great Brown Drake.
Seen here with a much smaller and more typical regional mayfly to its left, the Great Brown Drake was for several years infamous for swarming the lights and creating traffic hazards on bridges spanning the Susquehanna. During the past two weeks, nighttime flights of these giants have ventured out to gather at well lit locations in housing and business districts more than a dozen miles from the river. Earlier this century, this proclivity to wander probably led the Great Brown Drake to first invade silty segments of the Susquehanna as a colonizer from its native range in the Mississippi watershed.
Swarms of another storm-related visitor are being seen throughout the lower Susquehanna valley right now. Have you noticed the Wandering Gliders?
Throughout the month, swarms of Wandering Gliders, the most widespread dragonflies in the world, descended on areas hit by localized slow-moving thundershowers. Large numbers of these global travelers are known to get swept up within the thermal air masses that lead to these storms. In suitable terrain within the path of the downpours, they linger to search for flooded places where they can mate and deposit eggs. Wandering Gliders frequently mistake large parking lots at shopping malls, grocery stores, etc. for wetlands and will be seen in these areas depositing eggs upon the hoods and roofs of shiny motor vehicles, surfaces which appear puddle-like in their eyes.More dragonfly swarms are yet to come. Adult Common Green Darners are presently in the Lower Susquehanna River Watershed mating and depositing eggs within vegetated ponds, lakes, and wetlands. Beginning in August, adult Common Green Darners and other migratory species including Black Saddlebags, Carolina Saddlebags, Wandering Gliders, and Twelve-spotted Skimmers will begin swarming as they feed on flying insects (including lots of mosquitos and gnats) and start working their way toward the Atlantic Coastal Plain. Along the barrier islands by September, concentrations of southbound dragonflies can reach the thousands, particularly at choke points like Cape May, New Jersey, and Cape Charles, Virginia. So be sure to keep an eye on the sky for swarms of dragonflies during coming weeks. And don’t forget to check out our “Damselflies and Dragonflies” page by clicking the tab at the top of this page.
As the choruses of Brood XIV Periodical Cicadas fall silent for another seventeen years, the sounds of the more widespread annual Neotibicen cicadas are starting to be heard throughout the lower Susquehanna valley. These latter insects have a more abbreviated life cycle, spending just two to five years in the subterranean nymphal stage before appearing during mid-summer to breed. The emergence of these annual insects is not synchronized into broods, so some adults are found taking flight, singing, and mating every year. Over the centuries, male annual cicadas that emerged and commenced courtship songs earlier than July have certainly failed to successfully reproduce during Periodical Cicada years. So to avoid competition with the overwhelming drone of the seventeen-year cicadas that may emerge along with them, natural selection has delayed the maturation of the annual species until just after the periodicals have gone quiet. To see pictures and hear the sounds of our five (now 6 as of July 24th) species of annual cicadas, click the “Cicadas” tab at the top of this page.
Earlier today, we collected some mint leaves from the garden to make a batch of iced tea. Just prior to plunging them into boiling water, we noticed this Goldenrod Crab Spider (Misumena vatia) hiding in the foliage.Goldenrod Crab Spiders live among the stems and leaves of flowering plants. They are particularly fond of goldenrods, milkweeds, and other species that attract an abundance of flying insects. When the plants bloom, the spiders will use their white or yellow coloration to hide among the petals and disks of the flowers. From there, they ambush the visitors that stop by for a sample of nectar or pollen. In an effort to lure prey directly into their clutches, these acrobatic arachnids will even dangle among the clusters of blossoms with their legs spread like petals surrounding their disk-like body. This behavior helps inspire their other common name: Flower Crab Spider. Needless to say, this crab was spared the pot and instead returned to the garden to help keep the plants healthy and ecosystem in balance in our wildflower patch. So we’ll just be having tea, thank you.
While the heat and humidity of early summer blankets the region, Brood XIV Periodical Cicadas are wrapping up their courtship and breeding cycle for 2025. We’ve spent the past week visiting additional sites in and near the Lower Susquehanna River Watershed where their emergence is evident.
We begin in York County just to the west of the river and Conewago Falls in mostly forested terrain located just southeast of Gifford Pinchot State Park. Within this area, often called the Conewago Hills, a very localized population of cicadas could be heard in the woodlands surrounding the scattered homes along Bull Road. Despite the dominant drone of an abundance of singing Pharaoh Periodical Cicadas, we were able to hear and record the courtship song of a small number of the rare Little Seventeen-year Cicadas. Their lawn sprinkler-like pulsating songs help mate-seeking males penetrate the otherwise overwhelming chorus of the Pharaoh cicadas in the area.
The Little Seventeen-year Cicada’s (Magicicada septendecula) thorax is black between the eye and the origin of the wings. It is the rarest of the three species of seventeen-year cicadas.The underside of male (left) and female (right) Little Seventeen-year Cicadas shows narrow orange edges on the abdominal segments.
From the Conewago Hills we moved northwest into the section of southern Cumberland County known as South Mountain. Here, Pharaoh Periodical Cicadas were widespread in ridgetop forests along the Appalachian Trail, particularly in the area extending from Long Mountain in the east through Mount Holly to forests south of King’s Gap Environmental Education Center in the west.
Pharaoh Periodical Cicadas along the Appalachian Trail on South Mountain, Cumberland County, Pennsylvania. Like the cicadas we visited last week on the east side of the Susquehanna, this population is surviving on lands with a history of timber harvest and charcoal production to fuel nearby iron furnaces during the nineteenth century.
While on South Mountain, we opted for a side trip into the neighboring Potomac watershed of Frederick County, Maryland, where these hills ascend to greater altitude and are known as the Blue Ridge Mountains, a name that sticks with them all the way through Shenandoah National Park, the Great Smoky Mountains, and to their southern terminus in northwestern Georgia. We found a fragmented emergence of Pharaoh Periodical Cicadas atop the Catoctin Mountain section of the Blue Ridge just above the remains of Catoctin Furnace, again on lands that had been timbered to make charcoal to fuel iron production prior to their protection as vast expanses of forest.
A Pharaoh Periodical Cicada on Catoctin Mountain near Catoctin Furnace south of Thurmont, Maryland. These cicadas are not part of a Brood XIV emergence, but are instead a population of Brood X (2021) stragglers.A female Brood X Pharaoh Periodical Cicada straggler on Catoctin Mountain. The website “cicadamania.com” notes, “Experts (Gaye Williams, State Entomologist of Maryland, John Cooley of UCONN) have confirmed that there will be no Brood XIV cicadas for Maryland.”
Back in Pennsylvania, we’re on our way to the watersheds of the northernmost tributaries of the lower Susquehanna’s largest tributary, the Juniata River. There, we found Brood XIV cicadas more widespread and in larger numbers than occurred at previous sites. Both Pharaoh and Cassin’s Periodical Cicadas were seen and heard along Jack’s Mountain and the Kishacoquillas Creek north of Lewistown/Burnham in Mifflin County. To the north of the Kishacoquillas Valley and Stone Mountain in northernmost Huntingdon County, the choruses of the two species were again widespread, particularly along the forest edges in Greenwood Furnace State Park, Rothrock State Forest, and adjacent areas of the Standing Stone Creek watershed.
A view of the sound-generating tymbal on a male Pharaoh Periodical Cicada at Greenwood Furnace State Park. Rapid vibration of the tymbals by a set of specialized muscles generates the distinctive calls and courtship songs of the various cicada species. When handled, these tymbals can produce a harsh “panic call”. This distress sound could startle a would-be predator and provide the cicada with an opportunity to escape.The sound organs comprised of ribbed tymbals and specialized muscles on the male Cassin’s Periodical Cicada generate a “panic call” as well as the distinctive calls and songs used to penetrate the droning choruses of the more numerous Pharaoh Periodical Cicadas with which it shares a seventeen-year flight.Using their specialized sound organs, Cassin’s Periodical Cicadas generate a courtship song that usually includes buzzy phrases and ticking notes (first sound clip). The buzzing and ticking helps the male Cassin’s cicada penetrate the songs of the more numerous Pharaoh Periodical Cicadas in the area (second sound clip). When synchronized into a chorus that surges in volume, the songs of Cassin’s Periodical Cicadas can overcome the overwhelming drone of the nearby Pharaoh cicadas (third sound clip).After mating and before the lives of these seventeen-year cicadas draw to a close, the females need to deposit their fertilized eggs into the small end twigs of suitable trees. On a small hawthorn tree (Cretaegus species) along the edge of the forest at Greenwood Furnace State Park, this Pharaoh Periodical Cicada is using her ovipositor to make a slit in a twig and place her eggs.Simultaneously on the same little hawthorn tree, this female Cassin’s Periodical Cicada is depositing her fertilized eggs.
Within the last 48 hours, we visited one last location in the Lower Susquehanna River Watershed where Brood XIV Periodical Cicadas have emerged during 2025. In the anthracite coal country of Northumberland County, a flight of Pharaoh Periodical Cicadas is nearing its end. We found them to be quite abundant in forested areas of Zerbe Run between Big and Little Mountains around Trevorton and on the wooded slopes of Mahanoy Mountain south of nearby Shamokin. Line Mountain south of Gowen City had a substantial emergence as well.
A Brood XIV Pharaoh Periodical Cicada near Zerbe Run west of Trevorton, Northumberland County, Pennsylvania. The following sound clip features the fading chorus of these cicadas and some of the nesting birds that may actually be preying upon them: Yellow-billed Cuckoo, Red-eyed Vireo, and Northern Cardinal. Brown leaves reveal the end twigs where female Pharaoh Periodical Cicadas have deposited eggs during the last several weeks. During July, the larvae will hatch and drop to the ground to start a new generation of Brood XIV cicadas. As subterranean nymphs, they’ll spend the coming seventeen years feeding on small amounts of xylem sap from tree roots. In 2042, during the next Brood XIV emergence, these nymphs will come to the surface and take flight as adults.Evidence of egg deposition among foliage on Line Mountain at State Game Lands 229.Accumulations of deceased Pharaoh Periodical Cicadas on Line Mountain.Fallen cicadas that show any sign of life are being snatched up by predators such as this Eastern Gartersnake (Thamnophis sirtalis sirtalis). Meanwhile, the remainder of the biomass is picked apart by scavengers or is left to reducers for breakdown into fertilizer and organic matter for the forest. Nothing goes to waste.
To chart our travels, we’ve put together this map plotting the occurrence of significant flights of Periodical Cicadas during the 2025 emergence. Unlike the more densely distributed Brood X cicadas of 2021, the range of Brood XIV insects is noticeably fragmented, even in areas that are forested. We found it interesting how frequently we found Brood XIV cicadas on lands used as sources of lumber to make charcoal for fueling nineteenth-century iron furnace operations.
The furnaces at Greenwood Furnace State Park required the daily cutting of one acre of timber to make enough charcoal to fuel the iron-making process. Did keeping thousands of acres in various stages of forest succession to supply the charcoal needs of these operations aid the survival of earlier generations of Periodical Cicadas on these lands? Or, after the furnaces converted to coal for fuel, did the preservation of many of these parcels as state, federal, and private forests allow the cicadas to find refuge from the widespread impacts of agriculture and expanding urbanization in adjacent lands? Maybe it’s a little of both. We always bear in mind that annual insects and other animals are more than one hundred generations removed from the negative or positive impacts of the early years of the industrial age, but only about ten generations have passed since populations of seventeen-year Periodical Cicadas were directly influenced by these factors. What do you think?
Well, that’s a wrap. Please don’t forget to check out our new Cicadas page by clicking the “Cicadas” tab at the top of this page. Soon after the Periodical Cicadas are gone, the annual cicadas will be emerging and our page can help you identify the five species found regularly in the lower Susquehanna valley. ‘Til next time, keep buzzing!
Here are some sights and sounds from the ongoing emergence of Brood XIV Periodical Cicadas in the Lower Susquehanna River Watershed.
We begin in the easternmost spur of the lower basin where a sizeable emergence of cicadas can be seen and heard in the woodlands surrounding the headwaters of the Conestoga River in Berks County north of Morgantown. This flight extends east into Chester County and the French Creek drainage of the Schuylkill River watershed on State Game Lands 43 north of Elverson and consists of Pharaoh Periodical Cicadas (Magicicada septendecim), the most common species among 17-year broods.
A Brood XIV Pharaoh Periodical Cicada at State Game Lands 43 identified by the red bar extending from the eye to the wing root.The underside of the abdomen on a male Pharaoh Periodical Cicada showing the wide orange bars on each segment.Exuvia of a recently emerged Pharaoh Periodical Cicada.Soon after landing on a perch, a male Pharaoh Periodical Cicada will usually announce his presence by singing. It’s an attempt to quickly attract potential mates that may be in the vicinity.Pharaoh Periodical Cicadas ascending the branches of an oak.Gatherings of thousands of singing male Pharaoh Periodical Cicadas create a distinctive droning chorus.A receptive female will make a click sound with her wings to summon a suitable singing male for mating.While usually occurring in the safety of the trees, the breeding frenzy can spill over onto the ground where we happened to find this copulating pair.After mating, female cicadas make slits in the end twigs of selected trees into which they lay their eggs. The process of egg-laying and larval emergence will usually wilt and kill end growth on the affected branches, causing little harm to healthy trees. It’s similar to the trim you might give to a bonsai plant to keep it stout and sturdy.How long do Periodical Cicadas live? Well, by last week, we were already finding dead specimens by the thousands. Most of them had already completed their breeding cycle and planted the seeds for a new generation of Brood XIV cicadas.A deceased Pharaoh Periodical Cicada at the Fire Tower Parking Area at French Creek State Park. This specimen and a chorus on the hill’s forested south slope were the northeastern-most evidence of Brood XIV Periodical Cicadas we could find for the population cluster in portions of Berks, Chester, and Lancaster Counties around Morgantown.The abundance of Pharaoh Periodical Cicadas on State Game Lands 43 in Chester County has attracted numerous raptors, particularly wandering one-year-old birds that aren’t quite mature enough to nest. Among the sightings have been Red-tailed Hawks, Red-shouldered Hawks, Broad-winged Hawks, and at least three Mississippi Kites, a rarity on the Piedmont this far inland from the coastal plain. (See the post from June 5, 2021, for details on the occurrence of Mississippi Kites in northernmost Delaware during the Brood X emergence.)
From Route 82 north of Elverson to the west through the forested areas along Route 10 north of Morgantown and the Pennsylvania Turnpike, we found an abundance of Cassin’s Periodical Cicadas (Magicicada cassini) calling among the Pharaohs. This mix of Pharaoh and Cassin’s Periodical Cicadas extends west along the north side of the turnpike into Lancaster County and State Game Lands 52 on Black Creek north of Churchtown.
A Brood XIV Cassin’s Periodical Cicada at State Game Lands 52 is identified by the all-black margin between the eye and the wing root and……the black underside of the abdomen with no orange stripes.To penetrate the sounds of the more common Pharaoh Periodical Cicadas, male Cassin’s Periodical Cicadas gather in large concentrations to generate a loud, oscillating chorus. Its surging volume will usually exceed that of the Pharaohs singing in the vicinity.Mated Cassin’s Periodical Cicadas copulating at State Game Lands 52.The underside of copulating Cassin’s Periodical Cicadas.A pair of Cassin’s Periodical Cicadas at state Game Lands 52 in Lancaster County.
Further west in Cornwall, Lebanon County, a Brood XIV emergence can be found on similar forested terrain: the Triassic hills of the Newark Basin—rich in iron ore and renowned for furnace operations during the eighteenth and nineteenth centuries. Pharaoh Periodical Cicadas were the only species heard among this population that extends from Route 72 east through the woodlands along Route 322 into the northern edge of State Game Lands 156 in Lancaster County.
On the west side of the Susquehanna, yet another isolated population of Brood XIV Periodical Cicadas can be found in Perry County, just south of Duncannon on State Game Lands 170 on the slopes of “Cove Mountain”, the canoe-shaped convergence of the western termini of Peters and Second Mountains.
Pharaoh Periodical Cicadas dominated this Perry County chorus,…
…but we did detect at least one Cassin’s Cicada trying to find a mate.
A solitary Cassin’s Periodical Cicada issues a lonely song of short buzzes and ticking notes on State Game Lands 170. Fragmented populations, especially those that are only able to fly and increase their distribution every 17 years, often have a challenging time expanding and reuniting their disjointed ranges.
Not to say they aren’t present, but we have yet to detect the rarest species, Magicicada septendecula, the “Little Seventeen-year Cicada”, among the various populations of Brood XIV Periodical Cicadas emerging in the lower Susquehanna valley. For the coming two weeks or so until this brood is gone for another 17 years, the search continues.
For more on both annual and periodical cicada species in the Lower Susquehanna River Watershed, be sure to click the “Cicadas” tab at the top of this page!
With temperatures finally climbing to seasonable levels and with stormy sun filtering through the yellow-brown smoke coming our way courtesy of wildfires in Alberta and other parts of central Canada, we ventured out to see what might be basking in our local star’s refracted rays…
Dragonflies including this Black Saddlebags are now actively patrolling the edges of waterways and wetlands for prey and mates.Here we see a pair of Common Green Darners flying in tandem……and, having already mated, stopping at a suitable location for the female to oviposit the fertilized eggs onto submerged plant stems.A sunny day almost always brings out the reptiles, including these Painted Turtles…and the invasive Red-eared Slider, a native transplant from the American midwest.A really big Snapping Turtle will prey on almost anything, including other Snapping Turtles……but this one seems to be fascinated by something a lot smaller. Something like these juvenile Golden Shiners seen here schooling in the sun-drenched shallows.Turtles aren’t the only reptiles thriving in the heat. Northern Water Snakes (Nerodia sipedon sipedon) take full advantage of a sun-drenched rock to warm up after spending time in the chilly water of a stream.You know, no one loves a snake like another snake……and when it comes to these two snakes, it looks like love is in the air!Butterflies like this Spicebush Swallowtail enjoy time in the sun, even while seeking out minerals in a patch of moist soil.After its siblings darted into the familial burrow upon our approach, this juvenile Woodchuck instead sought the attention of its nurturing mother. Unlike its brothers and sisters, perhaps this little groundhog isn’t afraid of its own shadow. Or does the smoky haze have the youngster all confused about what does and doesn’t constitute as a shadow? Well, we can’t help you there, but you have a whole eight months to figure it out!
Its been four years to the day since we posted our account of the big Brood X Periodical Cicada flight of 2021 in the Lower Susquehanna River Watershed. With the Brood XIV clan of 17-year Periodical Cicadas getting ready fill the June air with their choruses in scattered parts of Pennsylvania’s Berks, Centre, Clinton, Franklin, Huntingdon, Juniata, Lancaster, Mifflin, Perry, Schuylkill, Snyder, Union, and York Counties right now, we thought it an appropriate time to open a new “Cicada” page here on the website. Included is a list of both the annually and periodically emerging species found in the lower Susquehanna valley, as well as a copy of the article and ID photos from the 2021 occurrence of Brood X. In coming months, we’ll be adding photos and maybe some sound clips of the different annual cicadas as well, so remember to check back from time to time for more content.
Note the wings and red eyes of this periodical cicada nymph. Within weeks it will join billions of others in a brief adult emergence to fly, mate, and then die.
In the short term, we’re going to pay a visit to the Brood XIV territory and will bring you updates as we get them. Until then, be sure to click the new “Cicadas” tab at the top of this page to brush up on your ID of the three species of 17-year Periodical Cicadas.
Not to worry. Cicadas are native, harmless, docile creatures when handled and they pose no threat to the long-term health of your healthy, well-established trees and other vegetation, so enjoy them while they’re here!
Here at susquehannawildlife.net headquarters, we really enjoy looking back in time at old black-and-white pictures. We even have an old black-and-white television that still operates quite well. But on a nice late-spring day, there’s no sense sitting around looking at that stuff when we could be outside tracking down some sightings of a few wonderful animals.
American Toad tadpoles have hatched from clusters of eggs deposited in this wet roadside ditch furnished with a clean supply of runoff filtered through a wide shoulder of early successional growth. Recent rains have kept their vernal nursery flooded, giving them the time they need to quickly mature into tiny toads and hop away before scorching summer heat dries up their natal home.Weekend rains and creek flooding haven’t stopped these Water Striders from pairing up to begin their breeding cycle.Around streams, lakes, ponds, and wetlands, the Common Whitetail is one of our most conspicuous dragonflies.Now that’s what we call a big beautiful bill, on a Great Blue Heron stalking fish.These mating Golden-backed Snipe Flies (Chrysopilus thoracicus) are predatory insects, as are their larvae. They are most frequently found in bottomland woods.About three feet in length, this Eastern Ratsnake is unusual because it still shows conspicuous remnants of the diamond-patterned markings it sported as a juvenile.The plumage of the Black-and-white Warbler lacks any of the vibrant colors found in the rainbow, but is nevertheless strikingly beautiful.This male Black-and-white Warbler appears a little bit ruffled as he dries out his feathers following a brief afternoon downpour. But as the sunshine returns, he bursts into song from a forest perch within the nesting territory he has chosen to defend. In addition to the vocalizations, this eye-catching plumage pattern helps advertise his presence to both prospective mates and would-be trespassers alike. But against the peeling bark of massive trees where this bird can often be found quietly feeding in a manner reminiscent of a nuthatch, the feathers can also provide a surprisingly effective means of camouflage.
Several weeks back, we removed the tick on the left from the editor’s neck. Upon returning from an outing earlier today, he discovered the one on the right crawling up his sock. It’s almost like they’re out to get him, so after tossing the day’s apparel into the washer, it was time to hit the showers posthaste. Because where there’s one, there are more. And you absolutely never want to spend the night with a tick.
Here’s a short preview of some of the finds you can expect during an outing in the Lower Susquehanna River Watershed’s forests this week…
The Mountain Laurel, designated as Pennsylvania’s state flower, is now in bloom.The buds of the Mountain Laurel remind us of a sugary frosting freshly squeezed from a baker’s pastry bag.The flowers of the Mountain Laurel, an evergreen understory shrub, invite pollinators to stop by for a sweet treat.Little Wood-Satyrs (Megisto cymela) are patrolling forest edges looking for mates and, to host their eggs and larvae, the stands of grasses they find most suitable.Many of the species of small butterflies we call skippers are now active. The Zabulon Skipper can be found patrolling grassy forest edges, particularly near streams, ponds, and wetlands.Among the showiest of our butterflies, the Red-spotted Purple (Limenitis arthemis astyanax) is seen here on the leaves of a Black Cherry, its favored host plant.Another red-spotted Purple seen picking up minerals from a dried up puddle depression on a gravel road.Butterfly observers will do well to pay a visit to the new Susquehanna Riverlands State Park on Furnace Road north of Hellam in York County, Pennsylvania.Upon arrival at Susquehanna Riverlands, drive back the gravel road for about a mile to the parking area at the edge of the agricultural field. Then, hike the trail through the woods and farm hedgerow to the Schull’s Rock overlook on the river. In the forests along this route, the understory is dominated by colonial stands of Common Pawpaw trees.Along the lookout trail to Schull’s Rock, the Common Pawpaws’ large leaves help them to shade out potentially fast-growing competition. In proper growing situations, pawpaws develop clonal suckers that mature over time to create colonial stands of a single genetic plant.A Common Pawpaw understory along the approach to Schull’s Rock.A colonial stand of Common Pawpaw along the trail leading to Schull’s Rock.During our recent visit to Schull’s Rock, dozens of Zebra Swallowtails were seen along the trail, many in the vicinity of their sole host plant, the Common Pawpaw. But even more were observed along the edges of the fields and woods where nectar sources like this Multiflora Rose were being visited by numbers of butterflies we normally see only among abundant species like Cabbage Whites. Absolutely amazing!And the view of the Susquehanna and the Shock’s Mills railroad bridge at the mouth of Codorus Creek is pretty good too!You can look for colonial stands of Common Pawpaw at other parks and preserves along the lower Susquehanna as well. Birds like this Hooded Warbler can sometimes be found among them in mature riparian forests along the steep slopes of the river gorge.A Baltimore Oriole in a Common Pawpaw along a forest edge.Meanwhile in the treetops, the spring thrust of Neotropical migrants is drawing to a close. The Blackpoll Warbler is typically one of the last to transit the lower Susquehanna valley on its way to northern coniferous forests for summer. They’ve had an unusually protracted movement through the region this spring, the earliest individuals reported during late April. Though very difficult to see in the canopy of the mature trees where it feeds and sings, hearing one is often a benchmark for senior birders each spring. Older observers have often said of the Blackpoll Warbler’s high-pitched song, a rapid series of insect-like staccato “tseet” notes, that it was the first they could no longer detect as their ears started losing sensitivity.In many tracts along the lower Susquehanna this spring, the American Redstart is turning out to be the most common nesting warbler. Conditions favoring their reproductive success in recent cycles, as well as good survival rates during their migrations and stays on wintering grounds, have filled many lowland forests with redstart songs in 2025. Is this the start of a trend or just an exceptionally good year? Time will tell.Yet one more reason for a stroll in local forests this week is the chance to see and hear the Rose-breasted Grosbeak. Look for these Neotropical relatives of the cardinal nesting on territories in mature stands of deciduous trees like this Yellow Poplar, a species also known as the Tuliptree.They spend nearly all their time among the canopy foliage of the largest timber……but pause frequently to repeat a song often described as something akin to that which might be performed by a robin subjected to voice lessons. The Rose-breasted Grosbeak is certainly a bird worth seeing and hearing.
Let us travel through time for just a little while to recall those sunny, late-spring days down on the farm—back when the rural landscape was a quiet, semi-secluded realm with little in the way of traffic, housing projects, or industrialized agriculture. Those among us who grew up on one of these family homesteads, or had friends who did, remember the joy of exploring the meadows, thickets, soggy springs, and woodlots they protected.
During much of the twentieth century, low-intensity agriculture provided a haven for wildlife. Periodic disturbances helped maintain cool-season grassland and early successional habitat for a number of species we currently find in decline.
For many of us, farmland was the first place we encountered and began to understand wildlife. Vast acreage provided an abundance of space to explore. And the discovery of each new creature provided an exciting experience.
Distributed by the Pennsylvania Game Commission, artist Ned Smith’s wildlife posters introduced many residents of the lower Susquehanna region to its birds and mammals. This poster of “Birds of Field and Garden” helped us learn what to expect and search for during our forays to the farm.
Today, high-intensity agriculture, relentless mowing, urban sprawl, and the increasing costs and demand for land have all conspired to seriously deplete habitat quality and quantity for many of the species we used to see on the local farm. Unfortunately for them, farm wildlife has largely been the victim of modern economics.
For old time’s sake, we recently passed a nostalgic afternoon at Middle Creek Wildlife Management Area examining what maintenance of traditional farm habitat has done and can do for breeding birds. Join us for a quick tour to remember how it used to be at the farm next door…
Always found nesting under the forebay of the barn, the Barn Swallow relentlessly pursued flying insects over the pond and meadow.Eastern Meadowlarks arrived during March and April to begin nesting in their namesake. Their song, “spring-of-the-year”, heralded the new season.Arriving in meadows and pastures during early May, the Eastern Kingbird provided for its nestlings by ambushing a variety of flying insects. By August, congregations of these birds could be found gathering along ponds and streams ahead of their fall migration.In the cherry grove down by the creek, the Orchard Oriole would be singing incessantly to defend its territory.Normally seed eaters through the colder months, American Goldfinches would regularly find a source of protein in the occupants of Eastern Tent Caterpillar nests.Along the wet margins of the creek, Yellow Warblers would nest in the shrubs and small trees.The “Traill’s Flycatcher” was a familiar find in low-lying areas of successional shrubs and small trees. Today, “Traill’s Flycatcher” is recognized as two distinct species, the Alder Flycatcher (Empidonax alnorum) and the Willow Flycatcher. In the lower Susquehanna valley, the latter (seen here) is by far the most common of the two.During the nineteenth century, Eastern Bluebirds became a rarity on lower Susquehanna farms due to a combination of factors: pesticide (DDT) use, habitat loss, and competition with other birds for nest sites. The species saw a resurgence beginning in the 1970s with discontinuation of DDT applications and widespread provision of nesting boxes. Around human habitations, competition with invasive House Sparrows continues to be detrimental to their success.Purple Martins suffered a similar fate to the bluebirds. The potential for their recovery remains dubious and they continue to be very local breeders, fussy about selection of suitable man-made provisions for nesting. After considerable effort, Purple Martins have at last been attracted to nest in the condos placed for their use at Middle Creek Wildlife Management Area. In the artificial gourds, there are nesting Tree Swallows, a species which also benefits from the placement of boxes intended for bluebirds.Abandoned fields and other successional habitats were and continue to be favored homes for Field Sparrows.At almost any time of year, roving bands of Cedar Waxwings would suddenly visit old field habitat looking for berries among the shrubs and other pioneering woody growth. In early summer, after most species have already hatched their young, nesting would commence and these fruit eaters would transform into accomplished fly catchers.During the twentieth century prior to the 1980s, Ring-necked Pheasant populations in the Lower Susquehanna River Watershed were comprised of breeding descendants of introduced birds supplemented by additional releases to maintain numbers sufficient for hunting. Year-round populations did and can reside in mosaic landscapes of early successional and grassland habitats, the latter including hay fields left unmowed through the nesting season.Red-winged Blackbirds have always been a fixture of hay fields and meadows on farms. While the increase in mowing frequency has reduced their nesting success, they have persevered as a species by nesting earlier than other birds and by utilizing other landscape features such as densely vegetated stormwater basins for breeding sites.Do you recall the last time you saw a Bobolink nesting in a hay field near you? Arriving in early May as a Neotropical migrant, the Bobolink requires a cool-season grassland such as hay field through at least July to complete its nesting cycle. Even earlier this century, we remember nesting Bobolinks being more widespread on farms throughout the region. Now, you almost have to go to Middle Creek if you want to see them.Formerly more widespread in hay fields throughout the lower Susquehanna valley, the native Grasshopper Sparrow is yet another species falling victim to early mowing and intensive farming.The solution to their dilemma is as advertised. Instead of cutting the grass, why not take heed of the example set here and cut back on the tens of thousands of acres that are excessively or needlessly mowed in the Lower Susquehanna River Watershed? How ’bout letting a significant percentage of your property regenerate as successional habitat as well? It can and does make a difference!Beautiful cool-season grasses waving in the spring breeze. Meadows and hay fields can be managed to function as cool-season grasslands to provide nesting opportunities for many of the species we used to find down on the farm.
When it comes to sitting down and watching an episode of Hollywood Squares or indulging in a game of Tic-Tac-Toe, those of us here at susquehannawildlife.net are quick to play right along. But when it comes to mixing it up with a Tick-Backed Doe or a Tick-Backed Buck like this one, you can count us out. Upon finding this button buck infested with engorged Deer Ticks and heading our way on a grassy trail, we decided to turn around and limit our walk to the gravel roadway where there was less of a chance of picking up any hitchhikers from the vegetation where this guy has been spending his time.
Neotropical birds are fairly well acquainted with repetitive periods of thundershowers. With that in mind, we decided not to waste this stormy Tuesday by remaining indoors.
Periods of rain need not put a damper on a day outdoors observing birds that wintered in a rain forest or other tropical environment.We hiked this utility right-of-way to the north of a heavy thunderstorm and found plenty of activity in the shrubby successional habitat there.Rain or shine, male Indigo Buntings were busy singing. All this exuberance is intended not only to establish and defend a nesting territory……but to attract the attention of a mate as well.Prior to the implementation of the intensive manicuring practices we see currently applied to most utility right-of-ways, shrubby thickets filled miles of these linear corridors to create a webbed network of early successional growth throughout the lower Susquehanna valley. Loss of this specialized habitat has led to the almost total elimination of the formerly common Blue-winged Warbler as a breeding species here.We found three male Blue-winged Warblers singing on territories in this bushy clearing where electric transmission lines pass over Third/Stony Mountain on State Game Lands 211.Their presence at this site is testament to the importance of maintaining corridors of quality successional habitat in the landscape.The Blue-winged Warbler is a Neotropical migrant with an easy-to-learn song. It’s a very simple, buzzy sounding “beeee-bzzz”.Another Neotropical species that nests in successional thickets is the Prairie Warbler (Setophaga discolor), seen here during one of this morning’s downpours.The Prairie Warbler can sometimes be found in stands of pioneer plants like Eastern Red Cedar on sites with barren soils or those that have been subjected to wildfire.The Hooded Warbler is fond of wooded thickets along the edge of forested land such as those in the Third/Stony Mountain utility right-of-way.The presence of a Mountain Laurel thicket also enhances a forest’s ability to host breeding Hooded Warblers.
We hope you enjoyed our walk in the rain as much as we did. If you venture out on a similar excursion, please remember this. The majority of the wild animals around us have busy lives, particularly at this time of year. Most don’t take a day off just because it rains—that includes ticks.
Be certain to check yourself for ticks, especially these very small Deer Ticks (Ixodes scapularis), also known as Black-legged Ticks. Deer Ticks are vigilantly looking for something to latch onto, even in the rain, and they can be vectors of Lyme disease. We found this adult female as a stowaway on the editor’s neck just before heading home from today’s stroll.
Here’s a look at six native shrubs and trees you can find blooming along forest edges in the lower Susquehanna valley right now.
The Black Locust (Robinia pseudoacacia), a member of the pea or legume family (Fabaceae), can be a dominant pioneer plant of sunny successional habitats, particularly on poor soils. Nodules along its roots fix nitrogen to help facilitate the growth of the intermediate and climax species of trees and shrubs that replace the pioneers. Initially armed with protective spines to reduce browsing, the Black Locust’s branches become mostly thornless as the tree matures.The Pinxter Flower, also known as the Pink Azalea, is certainly a contender for our most spectacular native blossoming shrub;……this Spicebush Swallowtail seems to like it too.When in bloom, the Black Cherry is a common sight in regional woodlands. Often seen already covered with blossoms when young and shrub-like, many of these trees will continue flowering and producing fruit throughout the decades required to reach a mature height of 60 feet or more.The Blackhaw is an understory shrub preferential to sun-dappled areas beneath a break in the forest canopy. Pollinated flowers later produce clusters of blue-black berries for birds and other wildlife.It’s easy to overlook the flowers of the Common Pawpaw. By the time the leaves are fully emerged and casting shade, blooming time is over.Nowadays, the Flowering Dogwood is most frequently encountered as a transplanted cultivar in city and suburban landscapes. In the wild, it is sparingly distributed throughout the region’s deciduous forests. These slow-growing little trees produce bright red berries that are quickly seized by a variety of birds upon ripening in the fall.
Local old timers might remember hearing folklore that equates the northward advance of the blooming of the Flowering Dogwoods with the progress of the American Shad’s spring spawning run up the river. While this is hardly a scientific proclamation, it is likely predicated on what had been some rather consistent observation prior to the construction of the lower Susquehanna’s hydroelectric dams. In fact, we’ve found it to be a useful way to remind us that it’s time for a trip to the river shoreline below Conowingo Dam to witness signs of the spring fish migration each year. We’re headed that way now and will summarize our sightings for you in days to come.
Tree blossoms open in response to the presence of adequate moisture and exposure to the warming effects of sunshine. Shad ascend the Susquehanna to spawn in response to suitable river flow and increasing water temperature. Sun and rain in the appropriate proportions can often conspire to synchronize otherwise unrelated events. Hence, a Flowering Dogwood in bloom along the edge of a mature forest means it’s time to go check out the shad run.
During a warm spell back in late March, adult Mason Bees began emerging from nest sites to begin mating. During recent days, we photographed the fertile females as they continued the process that will produce the next generation of these fruit-friendly pollinators.
Mason Bees visiting a box stocked with blocks of wood wherein holes have been drilled to provide nesting cavities for the egg-laying females.Mason Bee populations using man-made nesting structures in our region include two non-native species. Both show horn-like structures on the face, denoted here by the white hairline. To pollinate orchard crops, Osmia cornifrons, the Horn-faced Bee, was intentionally introduced to the eastern United States from northern Asia in 1978. Another early season pollinator, Osmia taurus, was accidentally introduced to North America from eastern Asia. O. taurus was first reported in Maryland and West Virginia in 2002 and had reached Pennsylvania by 2006-2008.Inside a nest cavity, a female Mason Bee will deposit pollen balls and an egg within each cell she creates using mud partitions. Cell by cell she fills the cavity with eggs and pollen. When the cavity is full, a thicker mud plug is constructed to seal off the entrance. After hatching, each larval bee will remain inside a cocoon within its individual cell consuming the enclosed pollen ball and maturing. After passing the winter in the nest, the new generation of adults will emerge in the spring…outermost cell occupants first.When reusing a nest cavity from a previous year, a female Mason Bee will excavate old partitions and other debris before starting her own nest. This female is removing saw dust and is possibly enlarging the hole on this new block of wood that we drilled just a few weeks ago.The majority of our Mason Bees prefer 1/4-inch holes, but some use the smaller 3/16-inch ones. Holes up to 3/8 of an inch in diameter are readily accepted by both Osmia cornifrons and taurus.A look at several female Mason Bees backed into their nest cavities to deposit eggs and pollen. Note the load of pollen adhering to the abdomen of the head-first bee at the bottom of the image and the yellow residue around the entrance to the cavity above it.Before a female Mason Bee has a chance to seal up a cell or to plug up the entrance to the cavity, a Drosophila fly (left) or other nest raider may show up to plunder a portion of the stash of pollen.Once filled with cells, each containing an egg and a pollen cache, the mother bee seals the nest cavity with a wall of mud.A bee seals up a 3/16-inch cavity with a mud barricade. Adult female Mason Bees may select smaller than usual holes to deposit eggs that will produce their smaller male young.Upon finishing the masonry job here, this female will move on to yet another cavity to deposit the balance of her fertilized eggs.One week later, the Mason Bees’ work is done.The adults are then soon to perish. But meanwhile, the next generation begins hatching and growing within the protection of the nest. We’ll see them early next spring.
Late winter is hardly the time of year one would expect to find a grasshopper bouncing around a rocky woodland clearing. But earlier this week during our visit to Rothrock State Forest in Huntingdon County, we photographed this Northern Green-striped Grasshopper (Chortophaga viridifasciata viridifasciata) nymph among the talus atop Tussey Mountain. Unlike the majority of other grasshopper species in the Susquehanna basin which overwinter as eggs, the Northern Green-striped hatches in late summer and progresses through all but the final one or two of its five developmental instars before passing the colder months in a sheltered location among fallen leaves, dried grasses, and decaying plant matter. Often the earliest of our grasshoppers to emerge, the Northern Green-striped nymph soon completes its final molts and reaches adulthood just in time for the warm days of late spring and early summer. Two color forms are common, brown and green, both possessing reddish-brown abdominal segments. Fuchsia-colored erythristic individuals are rare.
During the summer, the Lesser Angle-winged Katydid has little difficulty hiding among the lush green foliage of hardwood trees. Oft times, the only sign of its presence is its call, a series of short rapid rattles, “ttt—-tttt—-ttt”, issued with a second or two of silence between each rattle. The call is often part of the nocturnal chorus it shares with other species of katydids on warm evenings. Frost and freeze usually bring these annual breeding rituals to end. But during our current resurgence of warm autumn weather, we found this hardy survivor in a forest clearing where it has little hope of escaping notice among bare trees and earth-tone fallen leaves. As the afternoon temperature soared into the upper seventies, it further revealed its presence by striking up its tell-tale mating call, “ttt—-tttt—-ttt.”
During the past week, Uncle Tyler Dyer has been out searching for autumn leaves to add to his collection. One of the species he had not encountered in previous outings was the American Elm (Ulmus americana), so he made a special trip to see a rare mammoth specimen in a small neighborhood park (Park Place) along Chestnut Street between 5th and Quince Streets in Lebanon, Pennsylvania.
Possibly the largest and oldest remaining American Elm in the lower Susquehanna watershed, the Park Place tree in Lebanon exceeds 60 feet in height and may be more than 300 years of age. In the nearly one hundred years since Dutch elm disease (DED) first began killing elms in eastern North America, this tree has been spared the fatal effects of the infection. DED is caused by several species of microfungi (Ophiostoma ulmi, O. himal-ulmi, and O. novo-ulmi) spread by numerous bark beetle (Curculionidae) species. As early as 1928, infected beetles arrived in the United States from the Netherlands among shipments of logs.Leaves of the American Elm.
There’s still time to get out and see autumn foliage. With warmer weather upon us—at least temporarily—it’s a good time to go for a stroll. Who knows, you might find some spectacular leaves like these collected by Uncle Ty earlier this week. All were found adorning native plants!
Winged Sumac (Rhus copallina), a small native tree. In case you’re wondering, it’s not poisonous.Black Chokeberry (Photinia melanocarpa), a native shrub also known as Aronia. It produces black-colored fruits in summer.Red-osier Dogwood (Cornus sericea), a shrub that prefers wet or damp soils. It yields white fruits.Maple-leafed Viburnum (Viburnum acerifolium), a native shrub of upland forest understories.Highbush Blueberry (Vaccinium corymbosum), a native shrub and the source of many cultivated forms of the popular fruit.To identify your finds, be certain to click the “Trees, Shrubs, and Woody Vines” tab at the top of this page to check out Uncle Ty’s extensive collection.
During your foray to view the colorful foliage of the autumn landscape, a little effort will reveal much more than meets the eye of the casual observer.
Don’t just stand there like a bump on a log, go for a stroll, watch your step, and have a look around. There’s a lot to see out there!The dense understory of this forest on Blue Mountain consists almost exclusively of Witch-hazel (Hamamelis virginiana).Witch-hazel is unique among our native flowering shrubs; it blooms in autumn.Until we experience a heavy frost, some of our most beautiful butterflies, including this Common Buckeye, remain active along forest edges.An Eastern Tailed Blue.A Pearl Crescent.A Variegated Fritillary.A Painted Lady.The arrival of large numbers of Yellow-rumped Warblers heralds the transition to movements of migrants that will spend the colder months in temperate climates like ours instead of continuing on to the tropics. In winter, small numbers of “yellow-rumps” sometimes linger in the Lower Susquehanna River Watershed, as long as a supply of wild berries is readily available.The Palm Warbler, a persistent “tail wagger”, is another late-season migrant that occasionally spends the winter. The migration of these drab “Western Palm Warblers” will be followed in coming weeks by the more yellowish “Eastern Palm Warblers” of the eastern third of the species’ breeding range in Canada.White-throated Sparrows are southbound and easily observed right now. Many will remain along our brushy forest edges for winter.Another native sparrow, the familiar Dark-eyed Junco, is now arriving.The Yellow-bellied Sapsucker is a secretive migratory woodpecker that is currently moving through the region on its way to southern pine forests for the winter. Juveniles like this one in the lower right remain close to their parents during migration and continue to beg for food.The Pileated Woodpecker is a resident species in our mature forests and woodlands. We were showered by “sawdust” as we watched this one dismantling a rotted dead tree while searching for beetle grubs and other invertebrates.You may see Eastern Bluebirds year-round in the lower Susquehanna valley, but many are migratory. A southbound push is currently transiting our area.Mix your leaf watching with hawk watching by visiting a ridgetop vista like this one at Boyd Big Tree Preserve Conservation Area on Blue Mountain north of Harrisburg and you can double your pleasure.In addition to spectacular foliage, you stand a good chance of seeing an inquisitive Common Raven……or a migrating Red-tailed Hawk that gives you a good scream as it passes by……or a majestic Bald Eagle.You may even double your fun by seeing two Common Ravens……or a couple of migrating Red-tailed Hawks……or a pair of Bald Eagles passing thru.
You too can experience the joys of walking and chewing gum at the same time, so grab your field glasses, your camera, and your jacket, then spend lots of time outdoors this fall. You can see all of this and much more.
Don’t forget to click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page to help you find a place to see both fall foliage and migrating birds of prey in coming weeks. And click the “Trees, Shrubs, and Woody Vines” tab to find a photo guide that can help you identify the autumn leaves you encounter during your outings.
For the past several weeks, we’ve given you a look at the fallout of Neotropical songbirds on mornings following significant nocturnal flights of southbound migrants. Now let’s examine the diurnal (daytime) flights that have developed in recent days over parts of the lower Susquehanna basin and adjacent regions.
For those observing diurnal migrants, particularly at raptor-counting stations, the third week of September is prime time for large flights of tropics-bound Broad-winged Hawks. Winds from easterly directions during this year’s movements kept the greatest concentrations of these birds in the Ridge and Valley Province and upper areas of the Piedmont as they transited our region along a southwesterly heading. Counts topped 1,000 birds or more on at least one day at each of these lookouts during the past seven days. Meanwhile at hawk watches along the Piedmont/Atlantic Coastal Plain border, where flights topped 10,000 or more birds on the best days last fall, observers struggled to see 100 Broad-winged Hawks in a single day.
Dozens of migrating Broad-winged Hawks during a morning liftoff to the north of Blue Mountain.
Among the challenges counters faced while enumerating migratory Broad-winged Hawks this week was the often clear blue skies, a glaring sun, and the high altitude at which these raptors fly during the mid-day hours.
Large numbers of Broad-winged Hawks climbing on a thermal updraft to gain altitude can become increasingly difficult to spot in a clear blue sky.Higher and higher they go until they practically disappear from view.Cloud cover can help make locating really high-flying birds a bit easier, but they can sometimes climb into the lower portion of the cloud and vanish.
Another factor complicating the hawk counters’ tasks this week, particularly west of the Susquehanna River, was the widespread presence of another group of diurnal fliers.
Was it the migratory Blue Jays that are beginning to move through the area? No.Was it the increasing numbers of Sharp-shinned Hawks and other raptors? No.So what was it that complicated the hawkwatchers’ efforts to find high-flying Broad-winged Hawks during this week’s flights?Is it a bird? Is it a plane? No. And it’s nobody’s superhero either. It’s the non-native Spotted Lanternfly and it is now very numerous west of the Susquehanna and common enough to the east to make even experienced observers take a second look while scanning the skies for Broad-winged Hawks and other migrating raptors. Just how many do raptor counters have to contend with? Even where these invasive insects have become less populous in the lower Susquehanna valley, hundreds still fill the skies above forest clearings around hawk-counting stations including Waggoner’s Gap, Second Mountain, and Rocky Ridge County Park.Spotted Lanternfly populations explode with great vigor as they colonize areas with plenty of tender new growth on native, non-native, and cultivated shrubs, trees, and vines. Earlier this week, National Weather Service Doppler Radar in Pittsburgh, Pennsylvania, captured enormous mid-afternoon flights of Spotted Lanternflies in recently invaded areas of southwestern Pennsylvania and eastern Ohio. (NOAA/National Weather Service Doppler Radar image)A base velocity image consisting primarily of Spotted Lanternflies in southwestern Pennsylvania and eastern Ohio. (NOAA/National Weather Service Doppler Radar image)
As the Broad-winged Hawk migration draws to a close during the coming ten days, the occurrence of the one dozen other migratory diurnal raptors will be on the upswing. They generally fly at lower altitudes, often relying upon wind updrafts on the ridges for lift instead of high-rising thermal updrafts. They therefore present better observation opportunities for visitors at hawk watch lookouts and are less frequently confused with high-flying Spotted Lanternflies.
A Merlin seen earlier this week migrating through the Lower Susquehanna River Watershed. The numbers of migrating Merlins and other falcons will peak sometime in coming weeks.
Back on March 24th, we took a detailed look at the process involved in administering prescribed fire as a tool for managing grassland and early successional habitat. Today we’re going turn back the hands of time to give you a glimpse of how the treated site fared during the five months since the controlled burn. Let’s go back to Middle Creek Wildlife Management Area for a photo tour to see how things have come along…
Pennsylvania Game Commission crews administering prescribed fire on a grassland demonstration site back on March 16.By late May, native herbaceous perennial wildflowers including Joe-pye Weed had re-greened the site. One of the goals of the burn was to kill fire-sensitive woody plants, thus preventing the process of succession from reforesting the site.The scorched, lifeless remains of small trees and shrubs indicate that that goal was met.Because prescribed fire is administered in a mosaic pattern that permits some early successional growth to remain until the next burn, birds including this thicket-nesting Yellow-breasted Chat are able to take advantage of the mixed habitat during their breeding season in May and June.By August, the site is a haven for native plants and animals.The burn has promoted the growth and late-summer bloom of fire-tolerant native wildflowers and warm-season grasses……including Indiangrass,……Big Bluestem……Thin-leaved Coneflower (Rudbeckia triloba), a plant also known as Brown-eyed Susan,……and Joe-pye Weed, a plant butterflies find irresistible.Eastern Tiger Swallowtail collecting nectar from Joe-pye Weed.A black-morph Eastern Tiger Swallowtail collecting nectar from Spotted Knapweed (Centaurea steobe micranthos), a non-native invasive plant found growing in an area of the burn site missed by this year’s fire. While many non-native plants are unable to survive the flames and heat produced by prescribed fire, it isn’t an absolute cure-all. It doesn’t eliminate all invasive plants, it just keeps them from dominating a landscape by out-competing native species. Left unmanaged, Spotted Knapweed is a tough perennial invasive that can easily become one the species able to overtake a vulnerable grassland. It can be a stubborn survivor of some prescribed burns. On the plus side, butterflies really like it.By August, native grassland plants in the prescribed fire area were already providing an abundance of seeds for birds including this American Goldfinch.For larger birds like turkeys and pheasants, an abundance of Carolina Grasshoppers are providing a protein-dense food source in managed grasslands.And tiny flying insects, a nuisance to us as we take a stroll alongside the grasslands, are a meal taken on the wing by dragonflies including this Black Saddlebags.
Elsewhere around the refuge at Middle Creek, prescribed fire and other management techniques are providing high-quality grassland habitat for numerous species of nesting birds…
Bobolinks nested both in areas subjected to controlled burns……and in hay fields where mowing was delayed until the nesting season, including the fledging process, was completed earlier this month.As advertised, Grasshopper Sparrows nested in these fields as well.
We hope you enjoyed this short photo tour of grassland management practices. Now, we’d like to leave you with one last set of pictures—a set you may find as interesting as we found them. Each is of a different Eastern Cottontail, a species we found to be particularly common on prescribed fire sites when we took these images in late May. The first two are of the individuals we happened to be able to photograph in areas subjected to fire two months earlier in March. The latter two are of cottontails we happened to photograph elsewhere on the refuge in areas not in proximity to ground treated with a prescribed burn or exposed to accidental fire in recent years.
Eastern Cottontail at a site subjected to prescribed fire earlier in the spring.Eastern Cottontail at a site subjected to prescribed fire earlier in the spring.
These first two rabbits are living the good life in a warm-season grass wonderland.
Eastern Cottontail at a site not subjected to any recent fire activity.Eastern Cottontail at a site not subjected to any recent fire activity.
Oh Deer! Oh Deer! These last two rabbits have no clock to track the time; they have only ticks. Better not go for a stroll with them Alice—that’s no wonderland! I know, I know, it’s time to go. See ya later.
The Aphrodite Fritillary (Speyeria aphrodite), also known simply as the Aphrodite, is a brush-footed butterfly of deciduous, coniferous, and mixed forests. We found this female in a grassland margin between woodlots where prescribed fire was administered during the autumn of 2022 to reduce accumulations of natural fuels and an overabundance of invasive vegetation. A goal of the burn was to promote the growth of native species including the violets (Viola species) favored as larval host plants by this and other fritillaries.
A female Aphrodite Fritillary collecting nectar from a thistle flower.
By the time these adult butterflies make their reproductive flights in late summer, the violets that serve as larval host plants have gone dormant. To find patches of ground where the violets will come to life in spring, the female Aphrodite Fritillary has an ability to sense the presence of dormant roots, probably by smell. Upon finding an area where suitable violets will begin greening up next year, she’ll deposit her eggs. The eggs overwinter, then hatch to feed on the tender new violet leaves of spring.
A female Aphrodite Fritillary. A prescribed burn, when administered during spring to manage fritillary habitat, is applied only to a portion of the land parcel each year to avoid decimating an entire population of the larvae during the first instar of their life cycle, a time when they are vulnerable to fire.Our female Aphrodite Fritillary busily gathers nutritious nectar to provide sufficient energy for the critical process of mating and egg production. What’s the thistle that this goddess of love and procreation is pollinating?…It’s a non-native invasive, the Bull Thistle (Cirsium vulgare), a species that readily colonizes new areas by producing an abundance of airborne seeds. Continued management of this site with periodic applications of prescribed fire will prevent Bull Thistle and other invasives from overtaking the habitat during coming years.
Do you recall our “Photo of the Day” from seven months ago…
Here’s something to look forward to in the new year. The good citizens of East Donegal Township in Lancaster County have partnered with Alliance for the Chesapeake Bay to establish an extensive wildflower meadow on what had been a mowed field of turf grass at Riverside Park in the Susquehanna floodplain near Marietta. As the photo shows, the lawn plants have been eliminated in preparation for seeding with a diverse assortment of native grasses and wildflowers to provide habitat for birds and pollinators including butterflies, bees, and other insects. Once established, the meadow’s extensive vegetative growth will help reduce stormwater runoff by better infiltrating rainfall to recharge the aquifer. During flood events, the plantings will provide soil stabilization and increase the ability of the acreage to uptake nutrients, thus reducing the negative impact of major storms on the quality of water in the river and in Chesapeake Bay. Check the project’s progress by stopping by from time to time in 2024!
Well, here’s what that site looks like today…
The wildflowers, thousands of them, are now in bloom!Black-eyed Susan and Blue Vervain (Verbena hastata) dominate the assortment currently in flower.
And there are pollinating insects galore, most notably butterflies…
A Cabbage White collecting nectar on Blue Vervain.A Clouded or Orange Sulphur among the grasses in the meadow.A Silver-spotted Skipper.The Least Skipper is our tiniest butterfly.The Little Glassywing (Vernia verna), this one feeding on vervain nectar, deposits its eggs on Purpletop grass, which then functions as the host plant for this butterfly’s larvae.A Summer Azure (Celastrina neglecta) feeding on the nectar of a Black-eyed Susan.A Common Buckeye on a “Gloriosa Daisy”, a showy, large-flowered cultivar of Black-eyed Susan.A Red-winged Blackbird with a caterpillar found among the meadow’s lush growth.An Eastern Tiger Swallowtail on Blue Vervain. Nearby Yellow (Tulip) Poplars and other trees serve as host plants for this butterfly’s larvae.The black morph of the Eastern Tiger Swallowtail shows subdued shading in the wings that closely resembles the brilliant color patterns of the more familiar yellow form.The Sachem, this one visiting a Black-eyed Susan, is a variable species with a range that normally lies south of the 40th parallel, the line of latitude that intersects the Susquehanna in the area of the Conejohela Flats at Washington Boro.A Sachem visiting the blooms of Oxeye sunflower. During recent weeks, scorching winds from the south and southwest have transported an abundance of these vagrant skippers into the lower Susquehanna valley and beyond.A male Sachem approaching the bloom of a “Gloriosa Daisy”. Miles north of the 40th parallel, wandering Sachems are currently the most numerous of the butterflies at the Riverfront Park wildflower meadow.Here and there among the meadow’s plantings we noticed one of our favorites starting to flower, the Partridge Pea.Partridge Pea happens to be a host plant for another vagrant from the south, the big, lime-yellow Cloudless Sulphur. We saw at least half a dozen patrolling the meadow.The stars of the show are the Zebra Swallowtails, gorgeous butterflies that rely on stands of native Common Paw-paw trees in the river floodplain to host their eggs and larvae.The red-white-and-blue underside of a Zebra Swallowtail.WOW!
Why on earth would anyone waste their time, energy, and money mowing grass when they could have this? Won’t you please consider committing graminicide this fall? That’s right, kill that lawn—at least the majority of it. Then visit the Ernst Seed website, buy some “Native Northeast Wildlflower Mix” and/or other blends, and get your meadow planted in time for the 2025 growing season. Just think of all the new kinds of native plants and animals you’ll be seeing. It could change your life as well as theirs.
A Snowberry Clearwing (Hemaris diffinis), more commonly known as a hummingbird moth, visits the flowers of Blue Vervain in the Riverfront Park wildflower meadow.
Similar in appearance to the invasive Brown Marmorated Stink Bug, the Western Conifer Seed Bug (Leptoglossus occidentalis) is a seldom-noticed denizen of pines. During the 1950s, their range started expanding from the American west into the eastern states. Like the stink bug, the Western Conifer Seed Bug emits a buzzing sound in flight and is capable of releasing a nasty-smelling compound from scent glands when harassed. They feed on sap from developing pine cones, often causing deformities to the seeds, but posing no real harm to the trees. The Western Conifer Seed Bug causes greatest consternation during the fall when, like the invasive stink bugs, it gathers in numbers and attempts to enter homes to spend the winter. Those that get inside are mostly just an annoyance, but there have been reports of plumbing leaks caused by individual insects piercing PEX plastic water tubing with their mouths.
