A Natural History of Conewago Falls—The Waters of Three Mile Island
Chilly nights and shorter days have triggered the autumn migration of Neotropical birds. You may not have to go far to see these two travelers. Each is a species you may be able to find migrating through your neighborhood.
Beginning this evening at about 10:44 PM EDT, and lasting until almost 11 o’clock, the gaseous clouds from two of three TOMEX+ (Turbulent Oxygen Mixing Experiment) sounding rockets launched from NASA’s Wallops Island Flight Facility near Chincoteague, Virginia, were visible in the southern skies of much of the Lower Susquehanna River Watershed. From susquehannawildlife.net headquarters, we were able to see and photograph the glowing clouds created by these vapor releases. Within minutes, the contrail-like wisps were swept away by the swift thin air of the mesosphere, the area lying just below the thermosphere and the Kármán Line—the border of outer space 100 kilometers (62 miles) above sea level. According to NASA, “This mission aims to provide the clearest 3D view yet of turbulence in the region at the edge of space.”
It may seem hard to believe, but the autumn migration of shorebirds and many Neotropical songbirds is now well underway. To see the former in what we hope will be large numbers in good light, we timed a visit to the man-made freshwater impoundments at Bombay Hook National Wildlife Refuge near Smyrna, Delaware, to coincide with a high-tide during the mid-morning hours. Come along for a closer look…
Planning a visit? Here are some upcoming dates with morning high tides to coax the birds out of the tidal estuary and into good light in the freshwater impoundments on the west side of the tour road…
Tuesday, August 19 at approximately 07:00 AM EDT
Wednesday, August 20 at approximately 08:00 AM EDT
Thursday, August 21 at approximately 09:00 AM EDT
Friday, August 22 at approximately 10:00 AM EDT
Saturday, August 23 at approximately 11:00 AM EDT
Today’s NOAA/GOES satellite image serves as a little reminder of the big three. That’s right, it’s the three big “natural” disasters—wildfires, inland flooding, and coastal flooding (lucky for us, our region is at present millions of years removed from severe threats posed by the tectonic disasters—earthquakes, volcanoes, and tsunamis—and is not particularly prone to frequent tornadoes). Each continues to cause an increasing volume of property damage and threaten a greater number of lives because of where and how we choose to make our homes and erect our structures.
For all of human existence, the dynamics of the atmosphere have been shaping the topography and the ecosystems of the planet. In recent times, we’ve had the advantage of satellite technologies to show us spectacular images of atmospheric events as they happen. And through the various branches of science, we’ve come to understand the impact these events have upon the landscape and the people who live and/or work there.
Forestry sciences have helped us to understand how natural fuels, humidity, temperature, rainfall, soil moisture, wind, and human encroachment influence the frequency and severity of wildfires. These discoveries have led to changes in forest management and implementation of practices such as prescribed burns to reduce accumulated fuel loads. Because human development typically lowers soil moisture and brings along with it additional sources of ignition, many land managers and fire departments have warned of the ever increasing dangers of wildland-urban interface fires. These warnings have gone largely unheeded for more than four decades as millions of homes and other combustible structures have been erected within areas prone to fires capable of uncontrollable growth into disastrous conflagrations. The tinderbox wildlands—they’re a nice place to visit, but we ought not to live there!
Tropical storms and other sources of heavy precipitation bring about quite the hubbub over flooding. Meteorologists spend a lot of time explaining it all, but it’s almost as if no one pays any mind. For a people who check the weather forecast several times a day, every day of our adult life, just to get a leg up on how that weather is going to change day by day and hour by hour, you would think we would better anticipate the climatic events that happen over the long term. In particular, you would think we would have an awareness of our own individual susceptibility to flooding— a grasp of how, where, and why floods occur. You would think that repeated episodes of flooding would compel society to embrace an ethic that treated water as the valuable commodity it is. Yet, we all seem to follow the same patterns of behavior. First, we drain, dump, pipe, curb, channel, ditch, grade, pave, and pump to get the rain that falls upon our property off of our property. Then, the chump downstream gets really mad that we sent our water his way and flooded him out, so he takes the same measures to send even more water to the next poor slob down the line until finally the now polluted slurry of runoff floods the street, a cellar, a house, a business, or a stream—a stream that has been channelized so it no longer has a floodplain to absorb, hold, purify, and infiltrate the stormwater. Why was the stream channelized? So we could fill in the floodplain and build upon it of course. Two things come to mind here. First, if we’re going to be selfish enough to flood out our neighbors, then why shouldn’t we be totally selfish and keep for ourselves all the water that falls upon our place. After all, we’re going to need that water some day. And second, the floodplain is a nice place to visit, but we ought not to build there. Floodplains are for flooding; thousands of years of erosion have shaped them that way—it’s a gravity thing!
Next, we look at the lessons from geology, more specifically coastal geomorphology. Through these disciplines we know that the coastal plain—the flat land that spent most of the last 35.5 million years (the time since the meteor strike at the present-day mouth of Chesapeake Bay) as a beach or a tidal marsh—today stands mostly less than three dozen feet above sea level. We know that the sands forming barrier islands along the Atlantic seaboard, which are only several feet above sea level, shift their shape and position with the tides. Over the decades and centuries, these islands migrate and compensate for changes in climate and tidal patterns as well as sea levels. Behind their shifting dunes, vast tidal marshes are protected from seasonal storms including the periodic nor’easter or hurricane. Despite the importance of barrier island dynamics to the integrity of the bays and estuaries they protect, and despite their vulnerability to coastal storm surges, winds, and flooding, we choose to build there. In fact, the greatest population densities in the United States, and in many other countries of the world, are on the beach. It’s not because these hundreds of millions of people are fishing or loading/unloading ships for a living—it’s mostly for the view. Despite their importance to fisheries and other coastal life, we continue to alter and destroy the near-tidal areas of the the barrier islands and bays. We go to great expense to “save” for our uses the lands that should be getting inundated by rising sea levels to create new shallow tidewater zones. We waste spectacular amounts of money pumping sand back onto beaches to keep naturally migrating sediments from changing their shape and position in response to the tides. We keep putting more people and more capital at risk by urbanizing these low-lying areas. Building on the beach is absolute madness. It’s an ecological catastrophe from day one and a human catastrophe soon after.
All of the lands impacted by these natural events have two things in common. Each becomes a potential disaster area if people choose to construct their homes or businesses there. And each, if left in its wild state and given a buffer space from human activity, reacts with natural time-derived mechanisms in response to the same events. These mechanisms are often essential for provision of the unique ecosystems required by many of our most threatened wildlife species. Human encroachment into floodplains, wetlands, tidal marshes, beaches, and xeric uplands is a double-edged sword. It first decimates populations of these uncommon species by destroying and fragmenting their specialized habitats. Then, it sets the stage for the fires, floods, and other disasters that endanger the lives and property of the people living there. Considering the ramifications of building in these fire and flood susceptible areas, we can and should live somewhere else, especially when the wildlife requiring these places often can’t.
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.
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…
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.
Swarms of another storm-related visitor are being seen throughout the lower Susquehanna valley right now. Have you noticed the Wandering Gliders?
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.
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.
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.
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.
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.
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.
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.
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.
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.
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!
Just in time for the Flag Day/Father’s Day weekend, the Jordanella floridae we raise here at susquehannawildlife.net headquarters to help control hair algae in our planted aquaria are beginning to spawn.
In the wild, Jordanella floridae inhabits a variety of vegetated tropical wetlands and backwaters on the Florida peninsula. The species was first described there on Lake Munroe in 1879 by George Brown Goode and Tarleton Hoffman Bean, both of whom spent time working for the Smithsonian National Museum and the United States Fish Commission, the latter a forerunner of the U. S. Fish and Wildlife Service. Goode and Bean collaborated frequently, chronicling the occurrence of freshwater species like J. floridae as well as marine ichthyofauna. In 1896, the duo published Oceanic Ichthyology, an extensive study of pelagic and deep-sea fishes. Each experienced a prestigious career and has had numerous fish species named after him.
One of the earliest non-native fish species to be widely released into North American waterways was the Common Carp. Stocks brought to the United States were likely sourced from populations already naturalized throughout much of western Europe after introductions originating from the fish’s native range in Eurasia, probably including the Danube and other watersheds east through the Volga. In western Europe, the species promised to be an abundant and easily cultivated food source. Under the same premise, carp were transported to the United States during the early 1800s and widely introduced into streams, lakes, and rivers throughout the country.
Common Carp thrive in nutrient-rich waters, particularly those subjected to sewage discharge and agricultural runoff, conditions which were already prevalent during the Common Carp’s initial introduction and have remained widespread ever since. Within these polluted streams, lakes, and ponds, introduced carp feed aggressively on benthic organisms and plants, stirring up decaying organic matter (mulm) from the substrate. This process raises turbidity in the water column and releases excessive amounts of the nutrient phosphorus resulting in unusually large algal blooms. Algal blooms can block sunlight from the longer-lived oxygen-producing vascular plants that grow in submerged environs. Growing beneath a dense cloud or blanket of algae can compromise the vigor of oxygen-producing vascular plants and disable their biochemical functions within the aquatic ecosystem. As the short-lived algae die, the bacteria that decay them begin to place increased oxygen demands on the water. With less oxygen being produced by both the vascular plants and the algae, and with oxygen consumption increased by the activity of decomposers, conditions can become fatal for fish and other organisms. This process is known as eutrophication. Because Common Carp are among the species most tolerant of eutrophic conditions, they tend to thrive in the conditions they create while the native fishes perish.
Common Carp spawn in the spring, usually from late April through June, when the water temperature is as low as 58 degrees and as high as 83 degrees Fahrenheit. This activity is often triggered by a rapid increase in water temperature. In a small lake, this may be brought on by a string of sunny days in late April or May. On larger streams and rivers, the temperature spike that initiates the spawn may not occur until warm rains and runoff enter the stream during June.
Common Carp are one of the most widely farmed and eaten fish in all the world. Here in the United States, they were introduced beginning two hundred years ago because they were favorable to the palate, grew to large size quickly, and were a source of much needed food. Today, the Common Carp is seldom found on the American dinner plate. Yet, pound for pound, it is one of the most abundant fish in many of our waters, particularly in man-made lakes. Like some of our other most invasive species—including Blue Catfish, Flathead Catfish, and Northern Snakehead—Common Carp are perhaps the most edible of our freshwater fishes. For many cultures, they are an important staple. For others, they are a delicacy or holiday treat. In America, they do horrendous damage to aquatic ecosystems following establishment as a food crop that almost never gets harvested. Did you realize that on the internet, there are literally hundreds of recipes and culinary videos available to show you how to prepare delicious dishes made with Common Carp? It’s true. And for the cost of a fishing license, you can catch all you want, usually several pounds at a time. So why not give the marine fisheries a break? Take the big leap and learn to eat invasive freshwater species instead.
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…
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.
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.
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.
Renowned for its smooth, light-gray bark and its large size, the American Beech is one the most easily recognized trees found in climax forests throughout the lower Susquehanna valley. Preferring rich soils, this shade tolerant native produces an abundance of nutritious nuts for wildlife including deer, turkey, grouse, squirrels, woodpeckers, and a variety of songbirds.
If you’ve visited a stand of beech trees lately, you may have noticed that the canopy seems a little sparse in comparison to the foliage of the oaks, poplars, and other hardwood species in the vicinity.
A closer look reveals the cause. And yes, it’s big, big trouble.
While treatment for BLD is possible, it must be done early. Protecting an entire stand in a forest can be prohibitively expensive, but if you have a specimen tree or small grove you think you might like to save, click here for a Penn State Extension guide with more information.
An encounter from yesterday afternoon—you see it just the way we did…
You know, there’s no better time than the present to slow down and quit driving like a sociopath. After all, you wouldn’t want to murder Bambi’s mom and leave him all alone right now, would you?
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…
Currently in the Lower Susquehanna River Watershed, you can find these five species of herbaceous plants in full bloom. As they grow, they and others like them help to purify waters within their respective ecosystems by taking up nutrients—namely, the nitrogen and phosphorus that can lead to detrimental algal blooms and eutrophication in ponds, lakes, streams, and rivers.
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.
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.
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…
For many animals, an adequate shelter is paramount for their successful reproduction. Here’s a sample of some of the lower Susquehanna valley’s nest builders in action…
After repeatedly hearing the songs of these Neotropical migrants from among the foliage, we were finally able to get a look at them—but it required persistent effort.
Sometimes we have to count ourselves lucky if we see just one in five, ten, or even twenty of the birds we hear in the cover of the forest canopy or thicket. But that’s what makes this time of year so rewarding for the dedicated observer. The more time you spend out there, the more you’ll eventually discover. See you afield!
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.
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.
