Same Story, Different Ending

Once upon a time, a great panic spread throughout the lower Susquehanna region.  A destructive mob of invaders was overtaking our verdant land and was sure to decimate all in its path.  Clad in gray and butternut, they came by the thousands.  Flashing their crimson banners, they signaled their arrival at each new waypoint along their route.  The Pennsylvania government called upon the populace to heed the call and turn out in defense of the state.  Small bands of well-intentioned citizens tried in vain to turn back the progress of the hostiles—none succeeded.  But for a cadre of civic-minded elites and some small groups of college professors and their students, few responded to a call to confine the invasion along designated lines of containment.  Word spread quickly throughout the valley that farms had been overrun by waves of the merciless intruders.  Agrarians reported that their orchards had been stripped; they had lost all of the fruits of their labor.  Stories exaggerating the hideous appearance of the approaching aliens struck fear into the faint-of-heart.  The growing sentiment among the terror-stricken residents: this horde must be stopped before pestilence is visited upon everyone in the state!

And so, on the evening of June 28, 1863, just three days before the Battle of Gettysburg, the wooden Susquehanna River bridge at Columbia-Wrightsville was set ablaze just as Brigadier General John B. Gordon’s brigade of the invading Army of Northern Virginia approached the span’s west entrance preparing to cross to the eastern shore.  Thus, the rebel tide was turned away from the Susquehanna at the point some contend to be the authentic “High-water Mark of the Confederacy”.

Just one among an army of Spotted Lanternflies marching westbound across the Susquehanna River on the present-day Columbia-Wrightsville Bridge.  Same story, different ending.          

Smoky Skies in the Lower Susquehanna Region

During the coming two weeks, peak numbers of migrating Neotropical birds will be passing through the northeastern United States including the lower Susquehanna valley.  Hawk watches are staffed and observers are awaiting big flights of Broad-winged Hawks—hoping to see a thousand birds or more in a single day.

During its passage through the Lower Susquehanna River Watershed, an adult Broad-winged Hawk sails over Second Mountain Hawk Watch in Lebanon County, Pennsylvania.
A hatch-year/juvenile Broad-winged Hawk gazes toward hawk watchers on the ground.

Broad-winged hawks feed on rodents, amphibians, and a variety of large insects while on their breeding grounds in the forests of the northern United States and Canada.  They depart early, journeying to wintering areas in Central and South America before frost robs them of a reliable food supply.

The Carolina Saddlebags (Tramea carolina), this one photographed at Second Mountain Hawk Watch on September 8th, is the rarest of the lower Susquehanna region’s migratory dragonflies.  Autumn Broad-winged Hawk movements coincide with southbound flights of the Carolina Saddlebags and the more numerous migratory dragonfly species: Common Green Darner, Wandering Glider, Twelve-spotted Skimmer, and Black Saddlebags.  “Broad-wings” will often eat these and other dragonflies during migration and can sometimes be seen catching and feeding upon them while still soaring high overhead.

While migrating, Broad-winged Hawks climb to great altitudes on thermal updrafts and are notoriously difficult to see from ground level.  Bright sunny skies with no clouds to serve as a backdrop further complicate a hawk counter’s ability to spot passing birds.  Throughout the Lower Susquehanna River Watershed, the coming week promises to be especially challenging for those trying to observe and census the passage of high-flying Broad-winged Hawks.  The forecast of hot and humid weather is not so unusual, but the addition of smoke from fires in the western states promises to intensify the haze and create an especially irritating glare for those searching the skies for raptors.

Smoke from fires along the California coast and in central Utah can be seen streaming east this morning.  (NOAA/GOES image)
Smoke from western fires and humid air creates a band of haze in Ohio, Pennsylvania, New Jersey, and states to the south this morning.   (NOAA/GOES image)

 

A migrating Broad-winged Hawk in the glare of a hazy sky.  In addition to visibility problems, swarms of Spotted Lanternflies above the treetops make distant hawks difficult to discern for hawk watchers scanning the horizon with binoculars.

It may seem gloomy for the mid-September flights in 2021, but hawk watchers are hardy types.  They know that the birds won’t wait.  So if you want to see migrating “Broad-wings” and other species, you’ve got to get out there and look up while they’re passing through.

Migrating Ospreys typically fly low enough and are large enough to be spotted even during the haziest of conditions.
Bald Eagles like this fourth-year bird can ascend to great altitude, but their size usually prevents them from sneaking past a lookout unnoticed.
Peregrines escape notice not due to hazy sky conditions, but because they pass by so quickly.  They’re being seen at local hawk watches now through October.

These hawk watches in the Lower Susquehanna River Watershed are currently staffed by official counters and all welcome visitors:

    • Rocky Ridge County Park Hawk Watch—3699 Deininger Road off Mount Zion Road (Route 24) northeast of York, Pennsylvania.
    • Second Mountain Hawk Watch—off Cold Spring Road on the grounds of Fort Indiantown Gap in Lebanon County, Pennsylvania.
    • Waggoner’s Gap Hawk Watch—where Route 74 crosses Blue Mountain north of Carlisle, Pennsylvania.

—or you can just keep an eye on the sky from wherever you happen to be.  And don’t forget to check the trees and shrubs because warbler numbers are peaking too!  During recent days…

Northern Parula at Chiques Rock County Park in Lancaster County.
Black-and-white Warbler at Rocky Ridge County Park in York County.
Cape May Warbler at Chiques Rock County Park in Lancaster County.
Bay-breasted Warbler at Rocky Ridge County Park in York County.

Be on the Lookout for Mississippi Kites

Common sense tells us that Brood X Periodical Cicada emergence begins in the southern part of the population zone, where the ground temperatures reach 64° first, then progresses to the north as the weather warms.  In the forested hills where the lower Piedmont falls away onto the flat landscape of the Atlantic Coastal Plain in Maryland’s Cecil and Harford Counties, the hum of seventeen-year-old insects saturates a listener’s ears from all directions—the climax nears.

Periodical Cicadas, mostly Magicicada  septendecim, are well into their breeding cycle along the Piedmont-Atlantic Coastal Plain border right now.  Love is in the air.

With all that food flying around, you just knew something unusual was going to show up to eat it.  It’s a buffet.  It’s a smorgasbord.  It’s free, it’s all-you-can-eat, and it seems, at least for the moment, like it’s going to last forever.  You know it’ll draw a crowd.

The Mississippi Kite (Ictinia mississippiensis), a trim long-winged bird of prey, is a Neotropical migrant, an insect-eating friend of the farmer, and, as the name “kite” suggests, a buoyant flier.  It experiences no winter—breeding in the southern United States from April to July, then heading to South America for the remainder of the year.  Its diet consists mostly of large flying insects including beetles, leafhoppers, grasshoppers, dragonflies, and, you guessed it, cicadas.  Mississippi Kites frequently hunt in groups—usually catching and devouring their food while on the wing.  Pairs nest in woodlands, swamps, and in urban areas with ample prey.  They are well known for harmlessly swooping at people who happen to get too close to their nest.

Mississippi Kites nest regularly as far north as southernmost Virginia.  For at least three decades now, non-breeding second-year birds known as immatures have been noted as wanderers in the Mid-Atlantic States, particularly in late May and early June.  They are seen annually at Cape May, New Jersey.  They are rare, but usually seen at least once every year, along the Piedmont-Atlantic Coastal Plain border in northern Delaware, northeastern Maryland, and/or southeastern Pennsylvania.  Then came the Brood X Periodical Cicadas of 2021.

During the last week of May and these first days of June, there have been dozens of sightings of cicada-eating Mississippi Kites in locations along the lower Piedmont slope in Harford and Cecil Counties in Maryland, at “Bucktoe Creek Preserve” in southern Chester County, Pennsylvania, and in and near Newark in New Castle County, Delaware.  They are being seen daily right on the lower Susquehanna watershed’s doorstep.

Today, we journeyed just south of Mason’s and Dixon’s Delaware-Maryland-Pennsylvania triangle to White Clay Creek State Park along Route 896 north of Newark, Delaware.  Once there, we took a short bicycle ride into a wooded neighborhood across the street in Maryland to search for the Mississippi Kites that have been reported there in recent days.

Periodical Cicadas filled the treetops and the airspace just above them.
It wasn’t long before Mississippi Kites appeared over the trees along a hilltop clearing to snatch up cicadas for a morning meal.
This kite glides on autopilot as it holds a captured cicada in its talons and tears it apart with its hook-shaped bill.
At least ten Mississippi Kites have been seen simultaneously at this site or in nearby Newark during recent days. This morning, we saw six.
All the Mississippi Kites we saw today were second-year birds.  The banded tail is characteristic of both hatch-year (juvenile) and second-year (immature) Mississippi Kites.  Of course, at this time of year, hatch-year birds are still in the nest and not flying around pigging out on Periodical Cicadas.
The banded tail, gray underside, and white head of a second-year Mississippi Kite.  Though known as immature or subadult birds during their second year, there are records of Mississippi Kites successfully breeding at this age.  Recent wanderings into the Mid-Atlantic States and New England have led to a spotty expansion of the nesting range there.
Mississippi Kites in their second year undergo molt of their flight feathers. The timing can vary greatly among individual birds with diet among the factors affecting the process.  This bird is just beginning the replacement of its juvenile remiges and rectrices.
Tail molt beginning on this second-year Mississippi Kite.  These banded juvenile tail feathers will be replaced by a set of all-dark adult rectrices.
A second-year Mississippi Kite with an all-dark adult tail feather (rectrix).  An abundance of protein-rich cicadas should provide ample nutrition to keep the molt process going for this maturing bird, at least for another couple of weeks.  Relocating inland on the Piedmont could keep this and other kites well-nourished for even longer.

Will groups of Mississippi Kites develop a taste for our seventeen-year cicadas and move north into the Lower Susquehanna River Watershed?  Ah, to be young and a nomad—that’s the life.  Wandering on a whim with one goal in mind—food.  It could very well be that now’s the time to be on the lookout for Mississippi Kites, especially where Brood X Periodical Cicadas are abundant.

Identification of the Three Species of Brood X Periodical Cicadas

The emergence of Brood X Periodical Cicadas is now in full swing.  If you visit a forested area, you may hear the distant drone of very large concentrations of one or more of the three species that make up the Brood X event.   The increasing volume of a chorus tends to attract exponentially greater numbers of male cicadas from within an expanding radius, causing a swarm to grow larger and louder—attracting more and more females to the breeding site.

Holes in the ground where emerging Brood X Periodical Cicadas have come to the surface.
The exuvia of Periodical Cicadas that, following emergence from the soil, have ascended the trunk of an Eastern White Pine.  The exuvia is the exoskeletal remains of the cicada’s final molt from a nymph into a flying adult.

Each Periodical Cicada species has a distinctive song.  This song concentrates males of the same species at breeding sites—then draws in an abundance of females of the same species to complete the mating process.  Large gatherings of Periodical Cicadas can include all three species, but a close look at swarms on State Game Lands 145 in Lebanon County and State Game Lands 46 (Middle Creek Wildlife Management Area) in Lancaster County during recent days found marked separation by two of the three.  Most swarms were dominated by Magicicada septendecim, the largest, most widespread, and most common species.  However, nearly mono-specific swarms of M. cassinii, the second most numerous species, were found as well.  An exceptionally large one was northwest of the village of Colebrook on State Game Lands 145.  It was isolated by a tenth of a mile or more from numerous large gatherings of M. septendecim cicadas in the vicinity.  These M. cassinii cicadas, with a chorus so loud that it outdistanced the songs made by the nearby swarms of M. septendecim, seized the opportunity to separate both audibly and physically from the more dominant species, thus providing better likelihood of maximizing their breeding success.

Some of the tens of thousands of M. cassinii Periodical Cicadas in a concentration on State Game Lands 145 northwest of Colebrook in Lebanon County, Pennsylvania.  This swarm occupied deciduous and evergreen trees on several acres of a south-facing hillside.  To provide protection from predators and assure the chance of finding a mate “in the crowd”, lesser numbers of this and the rarer species, Magicicada septendecula, would need to merge into the swarms of the abundant M. septendecim Periodical Cicadas to breed.

The process of identifying Periodical Cicadas is best begun by listening to their choruses, songs, and calls.  After all, the sounds of cicadas will lead one to the locations where they are most abundant.  The two most common species, M. septendecim and M. cassinii, produce a buzzy chorus that, when comprised of hundreds or thousands of cicadas “singing” in unison, creates, when heard from a distance, a droning wail that can carry for a quarter of a mile or more.  It’s a surreal humming sound that may remind one of a space ship from a science fiction film.

Listen to the songs of individual cicadas at close range and you’ll hear a difference between the widespread M. septendecim “Pharaoh Periodical Cicada” and the other two species.  M. septendecim‘s song is often characterized as a drawn out version of the word “Pharaoh”, hence the species’ unofficial common name.  As part of their courtship ritual, “Pharaoh Periodical Cicadas” sometimes make a purring or cooing sound, which is often extended to sound like kee-ow, then sometimes revved up further to pha-raohM. cassinii, often known as “Cassin’s Periodical Cicada”, and the least common species, M. septendecula, often make scratchy clicking or rattling calls as a lead-in to their song.  Most observers will find little difficulty locating the widespread M. septendecim “Pharaoh Periodical Cicada” by sound, so listening for something different—the clicking call—is an easy way to zero in on the two less common species.

To penetrate the droning choruses of large numbers of “Pharaoh” and/or “Cassin’s Periodical Cicadas”, sparingly distributed M. septendecula cicadas have a noise-penetrating song consisting of a series of quick raspy notes with a staccato rhythm reminiscent of a pulsating lawn sprinkler.   It can often be differentiated by a listener even in the presence of a roaring chorus of one or both of the commoner species.  However, a word of caution is due.  To call in others of their kind, “Cassin’s Periodical Cicadas” can produce a courtship song similar to that of M. septendecula so that they too can penetrate the choruses of the enormous numbers of “Pharaoh Periodical Cicadas” that concentrate in many areas.  To play it safe, it’s best to have a good look at the cicadas you’re trying to identify.

M. cassinii Periodical Cicadas “singing” from a treetop at Colebrook, Lebanon County, Pennsylvania.  Clicking phrases are sure sign of the presence of this species and/or M. septendecula, the least likely of the three species to be encountered.  When in close proximity to a swarm, a listener will often notice the rising and falling volume of a chorus in a cycle that repeats every few seconds, an effect caused by cicadas attempting to synchronize their songs in a harmony with others in the group.  When courtship and mating is complete, female Periodical Cicadas will begin laying eggs in slits made in fresh new growth at the ends of branches on deciduous trees like the one seen here.

Visually identifying Brood X Periodical Cicadas to the species level is best done by looking for two key field marks—first, the presence or absence of orange between the eye and the root of the wings, and second, the presence or absence of orange bands on the underside of the abdomen.  Seeing these field marks clearly requires in-hand examination of the cicada in question.

Observing a perched Brood X Periodical Cicada can sometimes provide a view of the key field marks needed for identification of the species.  On the M. septendecim “Pharaoh Periodical Cicada” seen here, the orange patch between the eye and wing root and the orange bands on the underside of the abdomen are visible.
The abdomen of this perched M. cassinii “Cassin’s Periodical Cicada” appears, when viewed through the wings, to have orange bands.  But, examination in hand would show an all-black abdomen with glossy surfaces shining in the sunlight.  For accuracy, the up-close-and-personal look is necessary.
In the hand, cicadas can be better studied for key field marks.  M. septendecim (top) is larger than M. cassini (bottom) and M. septendecula, but the difference is not always apparent, particularly when a direct comparison cannot be made.

To reliably separate Brood X Periodical Cicadas by species, it is necessary to get a closeup view of the section of the thorax between the eye and the root (insertion) of the wings, plus a look at the underside of the abdomen.  Here’s what you’ll see…

Magicicada septendecim—“Pharaoh Periodical Cicada”

M. septendecim has an orange patch between the eye and the root of the wings.
The underside of M. septendecim’s abdomen has orange bands or stripes along the trailing edge of each segment. The width of the bands can vary, but is typically wider on males (left) than on females (right).

Magicicada cassinii—“Cassin’s Periodical Cicada”

The thorax of M. cassinii is black between the eye and the wing insertion.
The underside of M. cassinii’s abdomen is all black without orange bands or stripes in both the male (left) and female (right).

Magicicada septendecula

M. septendecula’s thorax is black between the eye and root of the wings.
The underside of M. septendecula’s abdomen has narrow orange bands or stripes along the trailing edge of each segment.  The width of the bands can differ.  Those of this male (left) are minimal and the bands on this female (right) are near the maximum for the species.

There you have it.  Get out and take a closer look at the Brood X Periodical Cicadas near you.

The abundant and widespread “Pharaoh Periodical Cicada” (M. septendecim).
It’ll all be over before long.  Accumulating remains of M. cassinii “Cassin’s Periodical Cicadas” beneath an Eastern White Pine at the site of the Colebrook State Game Lands swarm.

They’re Here

The Magi have arrived.   Emanating from the shadows of a nearby forest, you may hear the endless drone of what sounds like an extraterrestrial craft.  Then you get your first look at those beady red eyes set against a full suit of black armor—out of this world.  The Magicicada are here at last.

This exuvia, the leftover from a cicada’s final molt, tells us they are here.
A Brood X Periodical Cicada soon after emergence and final molt.
Not to worry, cicadas are harmless and docile when handled.  This is Magicicada septendecim, the largest and most common of our three species of Brood X seventeen-year cicadas.  They are currently emerging along south-facing borders of forests and wooded parks and lawns.
Magicicada septendecim can be recognized by the orange on the thorax behind each eye and in front of the wing insertions.  The smaller M. cassinii and M. septendecula have no orange coloration between the eye and wing.
Magicicada septendecim (seen here) has broad orange stripes on the abdomen.  M. cassinii has an all black abdomen and M. septendecula, the rarest species, has narrow well-defined orange stripes.

If you go out and about to observe Periodical Cicadas, keep an eye open for these species too…

Spotted Lanternflies, one of our most dreaded invasive species, have hatched.  These tiny nymphs about 5 millimetres in length were found feeding on a Virginia Creeper (Parthenocissus quinquefolia), a native vine in the grape family (Vitaceae).
Deer Ticks, also known as Black-legged Ticks, are hanging around on vegetation of all kinds looking to hitch a ride on a suitable host.  Don’t let it be you.  This adult female, less than 5 millimetres in length, was washed loose during an after-hike shower.

Seventeen Years Ago Today

Back in the spring of 2004, members of the Tri-County Conewago Creek Association (T.C.C.C.A.), a non-profit conservation group founded to improve water quality in Conewago Creek and its tributaries in Dauphin, Lancaster, and Lebanon Counties in Pennsylvania, were, in order to better understand the status of the flora and fauna in the watershed, frequently spending their weekends surveying the animal and plant life found in the drainage basin’s forests, streams, and farmlands.  This effort identified populations of several species of concern and helped supplement the more formal assessment that was used to determine the placement, scale, and scope of projects needed to reduce nutrient and erosion impairment in the Conewago’s waterways.

These regular outings happened to coincide with the Brood X Periodical Cicada emergence of 2004.  Back then, as the record keeper for the T.C.C.C.A.’s weekly survey forays, your editor decided to shade a map of the Conewago Creek Watershed showing where the group’s volunteers encountered choruses of the Brood X cicadas.  Fortunately, the map is still in the editor’s pile of stuff, and is reproduced here for you.

T.C.C.C.A.’s brochure map of the Conewago Creek Watershed (the Conewago east of the Susquehanna River), shaded with red ink in 2004 indicating locations where noisy choruses of Brood X Periodical Cicadas were found.  The range of the insects closely mirrors the forested areas of the watershed.  The nearly contiguous range along the southeast border includes the heavily wooded areas of Mount Gretna, State Game Lands 145, and the northwest slope of the diabase ridge that separates the Conewago from neighboring watersheds in Lancaster County.

A notation on the map (visible just above the cap on the pen) indicates May 16 as the emergence date for the cicadas in 2004—seventeen years ago today.

So why no seventeen-year cicadas yet in 2021?  The answer is ground temperature.  This year, by mid-April, Brood X Periodical Cicadas were just below the leaves and rocks, ready to break the surface.  But a cold month since then has stalled their emergence.  A thermometer pushed into the forest soil today showed readings of 60 degrees and less—at least four degrees below the temperature needed to get the nymphs crawling out of the dirt to climb rocks and vegetation where they’ll molt, dry, and take flight.

In the forested hills east of Conewago Falls, in the Conewago Creek Watershed, soil temperatures were as low as 54 degrees Fahrenheit today.

A warm week ahead with daytime temperatures in the eighties and nighttime lows in the fifties and sixties, instead of in the forties, should get the woodland soils warming.  Brood X Periodical Cicadas will be out and about in a jiffy—and you’ll hear all about it.

Coming up, The Great Eastern Brood.

Coming Soon, Very Soon: Brood X Periodical Cicadas

Yesterday, a hike through a peaceful ridgetop woods in the Furnace Hills of southern Lebanon County resulted in an interesting discovery.  It was extraordinarily quiet for a mid-April afternoon.  Bird life was sparse—just a pair of nesting White-breasted Nuthatches and a drumming Hairy Woodpecker.  A few deer scurried down the hillside.  There was little else to see or hear.  But if one were to have a look below the forest floor, they’d find out where the action is.

Not much action in the deer-browsed understory of this stand of hardwoods.
Upon discovery beneath a rock, this invertebrate quickly backed its way down the burrow, promptly seeking shelter in the underground section of the excavation.
A closeup of the same image reveals the red eyes of this Periodical Cicada (Magicicada species) nymph.  It has reached the end of seventeen years of slowly feeding upon the sap from a tree root to nourish its five instars (stages) of larval development.

2021 is an emergence year for Brood X, the “Great Eastern Brood”—the largest of the 15 surviving broods of Periodical Cicadas.  After seventeen years as subterranean larvae, the nymphs are presently positioned just below ground level, and they’re ready to see sunlight.  After tunneling upward from the deciduous tree roots from which they fed on small amounts of sap since 2004, they’re awaiting a steady ground temperature of about 64 degrees Fahrenheit before surfacing to climb a tree, shrub, or other object and undergo one last molt into an imago—a flying adult.

Here, approximately one dozen Periodical Cicada nymphs have tunneled into pre-emergence positions beneath a rock.  Seventeen-year Periodical Cicadas, sometimes mistakenly called “seventeen-year locusts”, are the longest-lived of our insects.
Note the wings and red eyes beneath the exoskeleton of this Periodical Cicada nymph. Within weeks it will join billions of others in a brief emergence to molt, dry, fly, mate, and die.
Adult (imago) Periodical Cicadas.  Brood X includes all three species of seventeen-year Periodical Cicadas: Magicicada septendecim, M. cassinii, and M. septendecula.  All Periodical Cicadas in the United States are found east of the Great Plains, the lack of trees there prohibiting the expansion of their range further west.  Seventeen-year life cycles account for twelve of the fifteen broods of Periodical Cicadas; the balance live for thirteen years.  The range of Brood X includes the lower Susquehanna basin and parts of Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, Ohio, Tennessee, Virginia, West Virginia, and the District of Columbia.  (United States Department of Agriculture/Agricultural Research Service image)
The flight of Periodical Cicadas peaks in late-May and June.  Annual Cicadas like this Silver-bellied Cicada emerge later in the season, peaking yearly in July and August,

The woodlots of the Lower Susquehanna River Watershed won’t be quiet for long.  Loud choruses of male Periodical Cicadas will soon roar through forest and verdant suburbia.  They’re looking for love, and they’re gonna die trying to find it.  And dozens and dozens of animal species will take advantage of the swarms to feed themselves and their young.  Yep, the woods are gonna be a lively place real soon.

Did you say Periodical Cicadas?  We can hardly wait!

Forest vs. Woodlot

Let’s take a quiet stroll through the forest to have a look around.  The spring awakening is underway and it’s a marvelous thing to behold.  You may think it a bit odd, but during this walk we’re not going to spend all of our time gazing up into the trees.  Instead, we’re going to investigate the happenings at ground level—life on the forest floor.

Rotting logs and leaf litter create the moisture retaining detritus in which mesic forest plants grow and thrive.  Note the presence of mosses and a vernal pool in this damp section of forest.
The earliest green leaves in the forest are often those of the Skunk Cabbage (Simplocarpus foetidus).  This member of the arum family gets a head start by growing in the warm waters of a spring seep or in a stream-fed wetland.  Like many native wildflowers of the forest, Skunk Cabbage takes advantage of early-springtime sun to flower and grow prior to the time in late April when deciduous trees grow foliage and cast shade beneath their canopy.
Among the bark of dead and downed trees, the Mourning Cloak butterfly (Nymphalis antiopa) hibernates for the winter.  It emerges to alight on sun-drenched surfaces in late winter and early spring.
Another hibernating forest butterfly that emerges on sunny early-spring days is the Eastern Comma (Polygonia comma), also known as the Hop Merchant.
In a small forest brook, a water strider (Gerridae) chases its shadow using the surface tension of the water to provide buoyancy.  Forests are essential for the protection of headwaters areas where our streams get their start.
Often flooded only in the springtime, fish-free pools of water known as vernal ponds are essential breeding habitat for many forest-dwelling amphibians.  Unfortunately, these ephemeral wetland sites often fall prey to collecting, dumping, filling, and vandalism by motorized and non-motorized off-roaders, sometimes resulting in the elimination of the populations of frogs, toads, and salamanders that use them.
Wood Frogs (Lithobates sylvaticus) emerge from hiding places among downed timber and leaf litter to journey to a nearby vernal pond where they begin calling still more Wood Frogs to the breeding site.
Wood Frog eggs must hatch and tadpoles must transform into terrestrial frogs before the pond dries up in the summertime.  It’s a risky means of reproduction, but it effectively evades the enormous appetites of fish.
When the egg laying is complete, adult Wood Frogs return to the forest and are seldom seen during the rest of the year.
In early spring, Painted Turtles emerge from hideouts in larger forest pools, particularly those in wooded swamps, to bask in sunny locations.
Dead standing trees, often called snags, are essential habitats for many species of forest wildlife.  There is an entire biological process, a micro-ecosystem, involved in the decay of a dead tree.  It includes fungi, bacteria, and various invertebrate animals that reduce wood into the detritus that nourishes and hydrates new forest growth.
Birds like this Red-headed Woodpecker feed on insects found in large snags and nest almost exclusively in them.  Many species of wildlife rely on dead trees, both standing and fallen, during all or part of their lives.

There certainly is more to a forest than the living trees.  If you’re hiking through a grove of timber getting snared in a maze of prickly Multiflora Rose (Rosa multiflora) and seeing little else but maybe a wild ungulate or two, then you’re in a has-been forest.  Logging, firewood collection, fragmentation, and other man-made disturbances inside and near forests take a collective toll on their composition, eventually turning them to mere woodlots.  Go enjoy the forests of the lower Susquehanna valley while you still can.  And remember to do it gently; we’re losing quality as well as quantity right now—so tread softly.

The White-tailed Deity in a woodlot infested by invasive tangles of Multiflora Rose.

Some Autumn Insects

With autumn coming to a close, let’s have a look at some of the fascinating insects (and a spider) that put on a show during some mild afternoons in the late months of 2019.

Bush Katydids (Scudderia species) are found in brushy habitats and along rural roadsides.  Their green summer color fades to brown, maroon, and gold to match the autumn foliage where they hide.  Bush katydids often remain active until a hard freeze finally does them in.
The Eastern Buck Moth (Hemileuca maia) is fuzzy, appearing to wear a warm coat for its autumn expeditions.  Adults emerge in October and may fly as late as December.  Females deposit their eggs on the twigs of Bear Oak (Quercus ilicifolia), Blackjack Oak (Q. marilandica), or Chestnut Oak (Q. montana), trees that, in our region, seem most favorable for the moth’s use when growing on burned barrens and mountain slopes.  The spiny caterpillars are known to feed only on the foliage of these few trees.  In the lower Susquehanna valley, the Eastern Buck Moth is rare because its specialized habitat is in short supply, and it’s all Smokey The Bear’s fault.
The Sachem (Atalopedes campestris) wanders north from the Atlantic Coastal Plain into the Susquehanna valley each summer.  In some years they become the most numerous small orange butterfly of all, particularly around home gardens.  The larvae will feed on Crabgrass (Digitaria species), but have not found success overwintering this far north.  By November, adults begin to look pretty drab.
From 1978 through 1982, the Asian Multicolored Lady Beetle (Harmonia axyridis) was introduced into the eastern states by the United States Department of Agriculture.  It has become a nuisance in many areas where it swarms, sometimes bites, and often overwinters in large smelly masses within homes and other warm buildings.  As you may have guessed, it’s possibly displacing some of the less aggressive native lady beetle species.
On a chilly afternoon, a sun-warmed Bold Jumping Spider (Phidippus audax) pounced and dispatched this sluggish worker Honey Bee (Apis mellifera) that was trying to gather pollen from a late-season Purple Coneflower bloom.  This spider is bold indeed.
Under bridges, inside bird nest boxes, and sometimes beneath porches, the female Pipe Organ Mud Dauber (Trypoxylon politum), a predatory wasp, builds these elaborate nests composed of long rows (pipes) of nursery cells.  Into each cell one or more paralyzed spiders is deposited along with one of the female’s eggs.  When hatched, each larva will feed upon the paralyzed spider(s) inside its cell, then pupate.  The pupae overwinter, then emerge from their cells as adults during the following spring.  In the autumn, males often stand guard at an entrance to the nest (look at the fifth pipe from the right) to prevent parasitic species, including some flies, from laying eggs on the pupae.  These wasps are not aggressive toward humans.
A Pipe Organ Mud Dauber (right) observes a neighboring nest of Paper Wasps (Polistes exclamans).  This latter species, a native of the southern United States, is currently expanding its range into the lower Susquehanna valley from the Atlantic Coastal Plain. These two wasps are known to regularly coexist.  Both will take advantage of man-made structures for their nest sites.  People using the picnic tables beneath this pavilion roof never noticed the hundreds of docile wasps above.
Those moody Eastern Yellowjackets (Vespula maculifrons) can get very temperamental during warm autumn days.  These wasps may appear to have no enemies, but away from areas impacted by man’s everyday activities, they do.  The Robber Fly (Promachus species) hunts like a flycatcher or other woodland bird, waiting on a perch along the forest’s edge for prey to pass by, then ambushing it, yellowjackets included.
The invasive Spotted Lanternfly, a native of eastern Asia, continues to spread destruction.  It established itself throughout much of the east side of the lower Susquehanna River during the summer and fall of 2019.  Their route of travel across the farmlands of the region intersects with plenty of vineyards to obliterate and few, if any, natural enemies.  Expect them to begin colonizing the west shore en masse during 2020.
In 2020, plan to roll a few Spotted Lanternflies over, enjoy the view, and wait for the crimson tide to pass.  With any luck, they’ll peak in a year or two.

SOURCES

Eaton, Eric R., and Kenn Kaufman.  2007.  Kaufman Field Guide to Insects of North America.  Houghton Mifflin Company.  New York, NY.

Spotted Lanternfly in the Lower Susquehanna River Watershed

Second Mountain Hawk Watch is located on a ridge top along the northern edge of the Fort Indiantown Gap Military Reservation and the southern edge of State Game Lands 211 in Lebanon County, Pennsylvania.  The valley on the north side of the ridge, also known as St. Anthony’s Wilderness, is drained to the Susquehanna by Stony Creek.  The valley to the south is drained toward the river by Indiantown Run, a tributary of Swatara Creek.

The hawk watch is able to operate at this prime location for observing the autumn migration of birds, butterflies, dragonflies, and bats through the courtesy of the Pennsylvania Game Commission and the Garrison Commander at Fort Indiantown Gap.  The Second Mountain Hawk Watch Association is a non-profit organization that staffs the count site daily throughout the season and reports data to the North American Hawk Watch Association (posted daily at hawkcount.org).

Today, Second Mountain Hawk Watch was populated by observers who enjoyed today’s break in the rainy weather with a visit to the lookout to see what birds might be on the move.  All were anxiously awaiting a big flight of Broad-winged Hawks, a forest-dwelling Neotropical species that often travels back to its wintering grounds in groups exceeding one hundred birds.  Each autumn, many inland hawk watches in the northeast experience at least one day in mid-September with a Broad-winged Hawk count exceeding 1,000 birds.  They are an early-season migrant and today’s southeast winds ahead of the remnants of Hurricane Florence (currently in the Carolinas) could push southwest-heading “Broad-wings” out of the Piedmont Province and into the Ridge and Valley Province for a pass by the Second Mountain lookout.

The flight turned out to be steady through the day with over three hundred Broad-winged Hawks sighted.  The largest group consisted of several dozen birds.  We would hope there are probably many more yet to come after the Florence rains pass through the northeast and out to sea by mid-week.  Also seen today were Bald Eagles, Ospreys, American Kestrels, and a migrating Red-headed Woodpecker.

Migrating Broad-winged Hawks circle on a thermal updraft above Second Mountain Hawk Watch to gain altitude before gliding away to the southwest.

Migrating insects included Monarch butterflies, and the three commonest species of migratory dragonflies: Wandering Glider, Black Saddlebags, and Common Green Darner.  The Common Green Darners swarmed the lookout by the dozens late in the afternoon and attracted a couple of American Kestrels, which had apparently set down from a day of migration.  American Kestrels and Broad-winged Hawks feed upon dragonflies and often migrate in tandem with them for at least a portion of their journey.

Still later, as the last of the Broad-winged Hawks descended from great heights and began passing by just above the trees looking for a place to settle down, a most unwelcome visitor arrived at the lookout.  It glided in from the St. Anthony’s Wilderness side of the ridge on showy crimson-red wings, then became nearly indiscernible from gray tree bark when it landed on a limb.  It was the dreaded and potentially invasive Spotted Lanternfly (Lycorma delicatula).  This large leafhopper is native to Asia and was first discovered in North America in the Oley Valley of eastern Berks County, Pennsylvania in 2014.  The larval stage is exceptionally damaging to cultivated grape and orchard crops.  It poses a threat to forest trees as well.  Despite efforts to contain the species through quarantine and other methods, it’s obviously spreading quickly.  Here on the Second Mountain lookout, we know that wind has a huge influence on the movement of birds and insects.  The east and southeast winds we’ve experienced for nearly a week may be carrying Spotted Lanternflies well out of their most recent range and into the forests of the Ridge and Valley Province.  We do know for certain that the Spotted Lanternfly has found its way into the Lower Susquehanna River Watershed.

This adult Spotted Lanternfly landed in a birch tree behind the observers at the Second Mountain Hawk Watch late this afternoon.  It was first recognized by its bright red wings as it glided from treetops on the north side of the lookout.

Noxious Benefactor

It’s sprayed with herbicides.  It’s mowed and mangled.  It’s ground to shreds with noisy weed-trimmers.  It’s scorned and maligned.  It’s been targeted for elimination by some governments because it’s undesirable and “noxious”.  And it has that four letter word in its name which dooms the fate of any plant that possesses it.   It’s the Common Milkweed, and it’s the center of activity in my garden at this time of year.  Yep, I said milk-WEED.

Now, you need to understand that my garden is small—less than 2,500 square feet.  There is no lawn, and there will be no lawn.  I’ll have nothing to do with the lawn nonsense.  Those of you who know me, know that the lawn, or anything that looks like lawn, and I are through.

Anyway, most of the plants in the garden are native species.  There are trees, numerous shrubs, some water features with aquatic plants, and filling the sunny margins is a mix of native grassland plants including Common Milkweed.  The unusually wet growing season in 2018 has been very kind to these plants.  They are still very green and lush.  And the animals that rely on them are having a banner year.  Have a look…

The flowers of the Common Milkweed were exceptionally fragrant this year.  At their peak in early June, their hyacinth-or lilac-like aroma was so prevalent, it drifted into the house and overwhelmed the stink of the neighbor’s filthy dumpster that he had placed 12 feet away from my walls (100 feet from his).
Common Milkweed attracts a pollinating Greenbottle Fly (Lucilia species).  The dumpster attracts the invasive House Fly (Musca domestica), carrier of dysentery, typhoid, and other wonderful diseases.  Are you following this?  Remember as we proceed, milkweed is noxious.
Busy Eastern Carpenter Bees (Xylocopa virginica) load up with pollen from the flowers of the Common Milkweed.
A Red Milkweed Beetle (Tetraopes tetrophthalmus) munches on a tender fresh Common Milkweed leaf in mid-June.
Following the pollination of the flowers, seed pods will begin to grow.  I trim these off the plants.  The removal of the extra weight allows most of the stems to remain erect through stormy weather.  You’ll still get new plants from underground runners.  As you may have guessed, I’m trying to keep these plants upright and strong to host Monarch butterfly larvae.

I’ve planted a variety of native grassland species to help support the milkweed structurally and to provide a more complete habitat for Monarch butterflies and other native insects.  This year, these plants are exceptionally colorful for late-August due to the abundance of rain.  The warm season grasses shown below are the four primary species found in the American tall-grass prairies and elsewhere.

Big Bluestem, a native warm-season grass in flower.
Little Bluestem (Schizachyrium scoparium “Fort Indiantown Gap”) in flower.  This variety grows on the tank range at the military base where the armored vehicles and prescribed burns substitute for the  herd animals and fires of the prairie to prevent succession and allow it to thrive.
Partridge Pea can tolerate sandy soil and is a host plant for vagrant Cloudless Sulphur butterflies.
Black-eyed Susan (Rudbeckia hirta) is a popular native grassland wildflower.
Indiangrass (Sorghastrum nutans) in flower.  This and the other native plants shown here are available as seed from Ernst Seed Company in Meadville (PA).  They have an unbelievably large selection of indigenous species.  You can plant a small plot or acres and acres using really good mixes blended for purposes ranging from reclaiming pipeline right-of-ways and strip mines to naturalizing backyard gardens.
A Red Admiral (Vanessa atalanta) butterfly, a migratory species like the Monarch, on Purple Coneflower (Echinacea purpurea).  Yes, it is that Echinacea.

There was Monarch activity in the garden today like I’ve never seen before—and it revolved around milkweed and the companion plants.

A female Monarch laying eggs on a Common Milkweed leaf.
A third instar Monarch caterpillar with Oleander Aphids (Aphis nerii) on a Common Milkweed leaf.  Both of these insect species absorb toxins from the milkweed which makes them distasteful to predators.
Fifth instar (left and center) and fourth instar (right) monarch caterpillars devour a Common Milkweed leaf.  There were over thirty of these caterpillars in just a ten by ten feet area this morning.  I hope if you’re keeping a habitat for Monarchs, you’re enjoying the same fortune right now!
A slow-moving Monarch stopped for a break after making the circuit to deposit eggs on milkweed throughout the garden.
Third instar (top), fourth instar (right), and fifth instar (left) Monarch caterpillars quickly consume the leaf of a Common Milkweed plant.  Caterpillars emerging from eggs deposited today may not have sufficient late-season food to complete the larval segment of their life cycle.  Need more milkweed!
After benefitting from the nourishment of the Common Milkweed plant, a fifth instar Monarch caterpillar begins pupation on Big Bluestem grass.
Two hours later, the chrysalis is complete.
Another chrysalis, this one on flowering Switchgrass just two feet away from the previous one.  An adult Monarch will emerge from this pupa to become part of what we hope will be the most populated southbound exodus for the species in over five years.
There it is, soon ready to fly away.  And all courtesy of the noxious milkweed.
A chrysalis can often be found on man-made objects too.  This one is on the rim of a flower pot.
Ornamental flowers can attract adult Monarch butterflies seeking nectar.  I am now more careful to select seeds and plants that have not been treated with neonicotinoid insecticides.  There’s growing concern over the impact these compounds may be having on pollinating species of animals.  Oh…and I don’t mow, whack, cut, mutilate, or spray herbicides on my milkweed  But you probably figured that out already.

 SOURCES

Eaton, Eric R., and Kenn Kaufman.  2007.  Kaufman Field Guide to Insects of North America.  Houghton Mifflin Company.  New York.

The Dungeon

There’s something frightening going on down there.  In the sand, beneath the plants on the shoreline, there’s a pile of soil next to a hole it’s been digging.  Now, it’s dragging something toward the tunnel it made.  What does it have?  Is that alive?

We know how the system works, the food chain that is.  The small stuff is eaten by the progressively bigger things, and there are fewer of the latter than there are of the former, thus the whole network keeps operating long-term.  Some things chew plants, others devour animals whole or in part, and then there are those, like us, that do both.  In the natural ecosystem, predators keep the numerous little critters from getting out of control and decimating certain other plant or animal populations and wrecking the whole business.  When man brings an invasive and potentially destructive species to a new area, occasionally we’re fortunate enough to have a native species adapt and begin to keep the invader under control by eating it.  It maintains the balance.  It’s easy enough to understand.

Japanese Beetles (Popillia japonica) seen here on Halberd-leaved Rose Mallow.  Without predation, exploding numbers of this invasive non-indigenous insect can defoliate and kill numerous species of plants in a given area.
The Song Sparrow (Melospiza melodia) is a generalist feeder, eating seeds and invertebrates including Japanese Beetles.  This species is the omnipresent year-round occupant of shoreline vegetation along the lower Susquehanna River.

Late summer days are marked by a change in the sounds coming from the forests surrounding the falls.  For birds, breeding season is ending, so the males cease their chorus of songs and insects take over the musical duties.  The buzzing of the male “Annual Cicada” (Tibicen) is the most familiar.  The female cicada lays its eggs in the twigs of trees.  After hatching, the nymphs drop to the ground and burrow to live and feed along tree roots for the next two to five years.  A dry exoskeleton clinging to a tree trunk is evidence that a nymph has emerged from the soil and flown away as an adult.  There are adult Annual Cicadas present every year.

An “Annual Cicada”, probably a Silver-bellied Cicada (Tibicen pruinosa), clings to a stem on a Halberd-leaved Rose Mallow at Conewago Falls.

For the adult cicada, there is danger.  It looks like an enormous bee.  It’s a Cicada Killer (Specius speciosus) wasp, and it will latch onto a cicada and begin stinging while both are in flight.  The stings soon paralyze the screeching panicked cicada.  The Cicada Killer then begins the task of airlifting and/or dragging its victim to the lair it has prepared.  The cicada is placed in one of more than a dozen cells in the tunnel complex where it will serve as food for the wasp’s larvae.  The wasp lays an egg on the cicada, then leaves and pushes the hole closed.  The egg hatches in a several days and the larval grub is on its own to feast upon the hapless cicada.

A Cicada Killer (Sphecius speciosus) along the river shoreline. Despite their intimidating appearance, they do not sting humans and can be quite docile when approached.

Other species in the Solitary Wasp family (Sphecidae) have similar life cycles using specific prey which they incapacitate to serve as sustenance for their larvae.

A Solitary Wasp, probably of the genus Ammophila, drags a paralyzed moth caterpillar to its breeding dungeon in the sandy soil at Conewago Falls.  For the victim, there is no escape from the crypt.

The Solitary Wasps are an important control on the populations of their respective prey.  Additionally, the wasp’s bizarre life cycle ensures a greater survival rate for its own offspring by providing sufficient food for each of its progeny before the egg beginning its life is ever put in place.  It’s complete family planning.

The cicadas reproduce quickly and, as a species, seem to endure the assault by Cicada Killers, birds, and other predators.  The Periodical Cicadas (Magicicada), with adult flights occurring as a massive swarm of an entire population every thirteen or seventeen years, survive as species by providing predators with so ample a supply of food that most of the adults go unmolested to complete reproduction.  Stay tuned, 2021 is due to be the next Periodical Cicada year in the vicinity of Conewago Falls.

SOURCES

Eaton, Eric R., and Kenn Kaufman.  2007.  Kaufman Field Guide to Insects of North America.  Houghton Mifflin Company.  New York.