Photo of the Day

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.

Colonies at War

Where does all the time go?  Already in 2024, half the calendar is in the trash and the gasoline and gunpowder gang’s biggest holiday of the year is upon us.  Instead of bringing you the memory-making odors of quick-burning sulfur or the noise and multi-faceted irritations that revved-up combustion engines bring, we thought it best to provide our readers with a taste of history for this Fourth of July.  Join us, won’t you, for a look back at one of the many events that shaped the landscape of our present-day world.


The early morning’s sun had just begun bathing the verdant gardens of the olde towne centre with a warm glowing light.  Birds were singing and the local folk were beginning to stir in preparation for their day’s chores.  Then, suddenly, something was stirring afoot.

The great battle had commenced.  Within minutes, thousands of colonists spilled onto the pavement to join the melee and defend their homes.

There’s no towne crier spreading the word on horseback.  Sensing aggression from a neighboring colony, a worker Pavement Ant (Tetramorium immigrans) functioning as a sentry issues the alert.  The aroma of pheromones produced by the sentry warns of danger and calls other workers to drop what their doing and instead respond to defend the nest.
Pavement Ants Join the Fray
Engaged in a dispute over territory, two colonies of Pavement Ants clash.  Though native to Europe, there is no evidence of Napoleonic tactics in their warfare.  All maneuver seems to be by chance.
Two Colonies of Pavement Ants in Battle
The workers doing the fighting are the sterile daughters of the one queen in each colony.  In addition to defending the nest, they do all the foraging and care for the queen’s eggs and young.  The young in each nest are its workers’ sisters and will include one or more new fertile queens.  These new queens, along with fertile males (brothers of the workers), develop wings and fly away to mate.  After mating, a young queen begins a new colony, excavating her own nest wherein she raises a first brood of workers to tend her forthcoming generation of eggs and young.  As the new colony grows, the queen’s workers expand the size of the underground nest by carrying particles of soil to the surface, depositing them around the entrance as telltale mounds.
Male Pavement Ant Amid Fighting Workers.
A winged male Pavement Ant gets caught in the fury of combat.  His primary role in life is to make a nuptial flight and mate with a queen to start a new colony.

The fighting was at close quarters—face to face with dominant soldiers sparing no effort to prevail in the struggle.

Pavement Ants in Combat
Worker Pavement Ants, all females, assume the role of soldiers to defend their nest, their colony, and their queen.

After about an hour had passed, the tide had turned and the fighting mass drifted to the south of the battle’s starting point.  The aggressors had been repelled.  The dispute was resolved—at least for a little while.

Pavement Ants in Battle
Thousands of Pavement Ants at the high-water mark of their desperate struggle.  It was a fierce, jaw-to-jaw contest to tear one’s opponent to pieces.
Pavement Ant Casualty
A winged Pavement Ant, probably a male and not a queen, falls victim to the fighting (upper right).  This casualty will not take part in a nuptial flight and will not contribute its colony’s DNA to a new population of ants.
Aggressive Pavement Ants Repelled
The tide turns and the invaders from the south are pushed back in the direction from whence they came.  Within minutes, the soldiers transitioned back to being workers.  No visual signs of the fight remained; casualties were carried away.

It wasn’t a struggle for independence.  And it wasn’t a fight for liberty.  For the sterile Pavement Ant worker, all the exertion and all the hazard of assuming the role of a soldier had but one purpose—to raise her sisters and become an aunt.  Long live the queen.

Fish Nurseries in the Susquehanna

Resilient to the pressures of flooding, ice scour, drought, and oft times really poor water quality, Water Willow (Dianthera americana, formerly Justicia americana) is the most common herbaceous plant on the Susquehanna’s non-forested alluvial islands.  Yet, few know this native wildflower by name or reputation.

Water Willow on Alluvial Island
Pure stands of emergent Water Willow endure at times brutal conditions on non-forested islands in the Susquenanna.
Water Willow (foreground) and Black Willow.
Alluvial deposits of sand, clay, gravel, and silt create ideal substrate for mats of Water Willow along shorelines of the Susquehanna and its larger tributaries.  Provided the loose substrate remains moist, this emergent thrives even when water levels retreat during periods of dry weather.  The woody plant in the background, the native Black Willow, shares similar soil preferences but is found growing on slightly higher ground as a non-emergent tree or shrub.  It is a member of the willow family (Salicaceae).
Water Willow in bloom.
In bloom now, the orchid-like flower of the Water Willow is a quick giveaway that it is not a close relative of the willow trees but is instead a member of the acanthus family (Acanthaceae) and is allied with the genus Ruellia, the wild petunias.

The spring of 2024 has been very kind to our beds of Water Willow.  Rainfall in the Susquehanna watershed has been frequent enough to maintain river levels just high enough to keep the roots of the plants wet.  During the interludes in storm activity, dry spells have rolled back any threat of flooding on the river’s main stem, thus eliminating chances of submerging the plants in muddy water and preventing the sun from keeping them warm, happy, and flowering early.  Thundershowers throughout the basin earlier this week have now raised the river a few inches to inundate the base of the plants and make mats of Water Willow favorable places for newly hatched fry and other young fish to take refuge while they grow.  Here’s a look…

Spottail Shiner
The Spottail Shiner (Notropis hudsonius) is a common native minnow of the Susquehanna.  This juvenile was found among several dozen small fish taking refuge in the cover of Water Willow below Conewago Falls.
Mimic Shiner
The Mimic Shiner (Notropis volucellus) is generally regarded to be a native transplant from the Mississippi drainage that has become established in the Susquehanna and many of its tributaries, possibly after introduction by way of bait buckets.  However, the fish tends to be very fragile and dies quickly upon handling, so its use and transport as a bait species may be impractical.  The Mimic Shiner is very common in around Conewago Falls.
Juvenile Mimic Shiner
A juvenile Mimic Shiner less than one inch in length found among flooded Water Willow below Conewago Falls earlier this week.
Juvenile Quillback
One of about a dozen juvenile Quillbacks (Carpiodes cyprinus) found in Water Willow just below Conewago Falls.  For spawning, local populations of this compact native species of carpsucker favor the gravel-bottomed pools among the Jurassic-Triassic boulders of the falls’ pothole rocks.  Probably hatched within the last eight weeks, this specimen was just one inch long.
Spotfin/Satinfin Shiner among Water Willow Rhizomes
As summer progresses, stands of emergent Water Willow begin to expand their size by sending out rhizomes.  Increasing numbers of small fish like this Spotfin/Satinfin Shiner (Cyprinella species) concentrate in the cover of the thickening vegetation.
Spotfin/Satinfin Shiners
The importance of these patches of emergent wildflowers (sounds weird, doesn’t it?) is demonstrated by the numbers of fish gathered within their underwater forest of stems and leaves by summertime.
Spotfin/Satinfin Shiners (Cyprinella species)
To protect them from burial by silt and to prevent them from being swept away by current, spawning Spotfin/Satinfin Shiners deposit their eggs in crevices of submerged rocks and wood, often in or near mats of Water Willow.  Males guard the eggs until hatching.  The fry must then take shelter among boulders, cobble, and plant cover.  Note the breeding-condition male in the upper right.
Green Sunfish
Panfish like this non-native Green Sunfish (Lepomis cyanellus) will often choose nesting sites in deeper water adjacent to beds of Water Willow, particularly if submerged growth like this Water Stargrass adds to the availability of cover for their young after hatching.
Smallmouth Bass
Smallmouth Bass gather in a pool adjacent to a Water Willow-covered island.  These non-native predators rely on beds of these indigenous plants to provide habitat for their young, then, after spawning, lurk in the waters surrounding them to ambush less-than-vigilant minnows and other victims.

By now you’ve come to appreciate the importance of Water Willow to the sustainability of our populations of fish and other aquatic life.  Like similar habitat features that reduce sediment runoff and nutrient pollution, undisturbed stands of terrestrial, emergent, and submerged native plant species are essential to the viability of our freshwater food webs.

Photo of the Day

Clubbed Mydas Flies in Copula
Love is in the Air- The conspicuously large Clubbed Mydas Fly (Mydas clavatus) is a harmless mimic of the spider wasps (Pompilidae).  They carry their masquerade to the extreme with bold behavior that includes pumping of their abdomen to simulate an ability to sting.  Adults visit flowers to feed on pollen and nectar while the larvae are predatory, relying on a diet of scarab beetles (Scarabaeidae) which they find crawling within the dead and rotting wood where they reside.  When mating, adults fly around in copula, reminding one of “love bugs” and other members of the fly family Bibionidae, the march flies.  This mating pair was photographed along the Susquehanna at Conewago Falls. 

It’s Been a Stinkin’ Hot Week

Turkey Vulture and Road-killed Woodchuck
…but the stench would have been a lot worse without our friendly neighborhood scavengers around to clean up our mess.  Turkey Vultures thrive in scorching temperatures, riding thermal updrafts to patrol the countryside for roadkill victims like this unfortunate Woodchuck.

Colorful Damselflies

Check out these glistening gems—mating damselflies on a late spring afternoon.

Powdered Dancers
It’s two pairs of Powdered Dancers, males clasping ovipositing females, a striped blue form female on the left and a brown form female on the right.
Stream Bluet
A male Stream Bluet (Enallagma exsulans) perched on a grass stem in a vegetated buffer along a rehabilitated creek.
Stream Bluets
A pair of Stream Bluets, male clasping female.
Ebony Jewelwing
A male Ebony Jewelwing (Calopteryx maculata) looking for a mate.
A female Ebony Jewelwing
There she is, the shy female Ebony Jewelwing among the shelter of some streamside foliage.
A male Variable Dancer.
A male Variable Dancer (Argia fumipennis).
Variable Dancers
A mating pair of Variable Dancers, male clasping female.
Variable Dancers
Two mating pairs of Variable Dancers, males clasping ovipositing females.
Powdered Dancers and Variable Dancers
Two pairs of mating damselflies, Powdered Dancers (left) and Variable Dancers (right), with both females ovipositing.
A male Double-striped Bluet
A male Double-striped Bluet (Enallagma basidens) showing his stuff.
A female Fragile Forktail
A female Fragile Forktail.
Powdered Dancers and Fragile Forktail
Mating Powdered Dancers, male clasping female, and an ovipositing female Fragile Forktail.
Mating Orange Bluets in wheel position.
A pair of mating Orange Bluets (Enallagma signatum) in wheel position, male above and female below.

Aren’t they precious?  You bet they are.

To see these and other damselflies, as well as their larger cousins the dragonflies, be certain to visit your favorite vegetated lake, pond, stream, or wetland on a sunny afternoon.  You might be surprised by the variety of colorful species you can find.

And to help identify your sightings, don’t forget to visit our “Damselflies and Dragonflies” page by clicking the tab bearing that name at the top of this page.

Photo(s) of the Day

How ’bout a Two-for-the-Price-of-One Father’s Day Special?  You got it!

Adult male and juvenile Pileated Woodpeckers.
Woodrow the Pileated Woodpecker (left) sure has collected a throat-load of tasty morsels, but he wouldn’t dare keep them all to himself;…
Male Pileated Woodpecker feeding young.
…he’s forced to share his meal with Little Woody, otherwise the begging will never stop.

Photo of the Day

Long-legged Fly
The minuscule Long-legged Fly (Condylostylus species) is a predatory consumer of soft-bodied invertebrates.  In the headquarters garden, we found this individual and others scurrying around on the leaves of Common Milkweed where they may be seeking to gobble up infesting aphids.

Schools of Juvenile Largemouth Bass Learning to Survive

Yesterday, while photographing damselflies on a rehabilitated segment of a warmwater lower Susquehanna valley stream, we noticed some oddly chunky small fish gathered on the surface of a pool along the shoreline.

Damselflies and Small Fish
Perched damselflies and some sort of robust little fish feeding nearby.

Upon further inspection, they appeared to be fingerlings of some type of sunfish or bass.  Time for a closer look.

Juvenile Largemouth Bass
At just one inch in length, these juvenile Largemouth Bass (Micropterus salmoides) are already showing signs of the dark lateral stripe that so easily identifies the adult fish.
Adult Largemouth Bass on Spawning Bed
Adult Largemouth Bass began spawning among nearby beds of Spatterdock and other emergent and submerged aquatic vegetation about one month ago, just as water temperatures stabilized to a minimum of the low sixties for several days and nights.  Each female can lay thousands of eggs.  Only those that are successfully fertilized by the attending male have a chance to hatch.
Juvenile Largemouth Bass
Largemouth Bass eggs can hatch as soon as ten days after being deposited in the nest by the female and fertilized by the male.  The fry linger in the nest for another week consuming the nutrition contained in their attached yolk sac.
Juvenile Largemouth Bass
The juvenile fish are then ready to leave the nest and begin feeding on zooplankton.
Juvenile Largemouth Bass
Young largemouths often gather in schools to feed in waters near their birthplace.  As they grow, they soon begin consuming small invertebrates and tiny fish.  But for young bass, the hazards are many.  These juveniles can become victims of a host of predatory insects, crayfish, piscivorous birds, and bigger fish.  Then too, Largemouth Bass, like most other species  of fishes, are cannibalistic and will consume others of their own kind.  Of the thousands of eggs produced by a mating pair, natural selection determines which, if any, of their progeny will survive to reproduce and sustain their genetic line.

In the Lower Susquehanna River Watershed, the Largemouth Bass is an introduced species, a native transplant from the Mississippi watershed and Atlantic Slope drainages south of the Chesapeake.

The Acadian Flycatcher: A Shady Character

You’ve probably never noticed the Acadian Flycatcher (Empidonax virescens).  This small Neotropical songbird arrives in the Lower Susquehanna River Watershed during mid-May to breed in the dense shade of mature forests, often along steep slopes adjacent to a brook or creek.  It’s quick, sneezy song—“pit-see” or “wee-seet”—heard emanating from the shadows of the woodland understory is often the first and only sign of their presence.

Acadian Flycatcher
Of the five species of similar-looking Empidonax flycatchers that regularly occur in our region, the Acadian is the only one to nest in the forest interior.  These insectivores shy away from edge habitat and clearings that disturb the closed canopy of mature trees.

One of the more fascinating  habits of the Acadian Flycatcher is their selection of a nesting location.  While many species try to conceal their nests in tree cavities, dense foliage, or some other form of cover, this clever songbird constructs a cup using tiny twigs and leaves and places it near the end of a small branch on a small tree.  The nest is sometimes very easily seen, but for climbing scroungers looking to plunder eggs or helpless young birds, it’s practically out of reach.

Acadian Flycatcher on Nest
A female Acadian Flycatcher on its nest incubating eggs.
Acadian Flycatcher Nest
The white arrow points to the Acadian Flycatcher nest seen in the previous image. The dark-colored limb appears close, but this nest is perched precariously close to the end of a leafy branch and is hanging free and clear above the stream.  When leaving the nest, the young birds that are destined to survive must avoid a tumble into the waterway.

To guard against airborne threats, Acadian Flycatcher parents are vigilant defenders of the space around their nest.

Carolina Chickadee
When this curious juvenile Carolina Chickadee wandered into the flycatcher’s nest tree…
Acadian Flycatcher
…mom came out fighting!  It may be an overreaction, but nesting birds often have a zero-tolerance policy for invaders within their “zone”.

Moments later, things settle down and the waiting continues…

Back on the nest, mom, the eggs, and eventually the young will spend the next several weeks riding the wind atop this flimsy branch in their shady forest home.

Photo of the Day

Ninebark
The bright-red flower buds of the Ninebark (Physocarpus opulifolius) precede clusters of white blooms that will, in coming weeks, attract a variety of butterflies and other pollinators to this indigenous shrub.  Its peeling bark and colorful deciduous leaves attract interest throughout the year.  In the lower Susquehanna watershed, Ninebark is most frequently found growing along stream banks.  It will often thrive on steep slopes with moist soils, so is useful as an erosion control species as well.  To add it to your refuge’s landscape, look for it at nurseries that stock native plants.  Once there, you’ll find a variety of cultivars that are sure to satisfy even the fussiest of gardeners.

Photo of the Day

Male Twelve-spotted Skimmer
Even in flight, the Twelve-spotted Skimmer is easily identified by the conspicuous color pattern in its wings.  Look for it now around vegetated ponds and lakes.  Later, during late summer and early fall, this widespread species can often be seen among southbound movements of other migratory dragonflies.

Photo of the Day

Black-crowned Night Heron
Once a widespread breeding bird in the lower Susquehanna River basin, the Black-crowned Night Heron (Nycticorax nycticorax) is today listed as an endangered species in Pennsylvania.  Along many of the region’s creeks where they formerly nested, pollution and year-round populations of hand-fed waterfowl have eliminated or severely reduced numbers of the night heron’s prey species including amphibians, aquatic invertebrates (particularly crayfish), and a variety of minnows and other fishes.

What’s in a Name?

March Fly, Bibio townesui
As the month of June gets underway, we spotted this male March Fly (Bibio species) visiting the susquehannawildlife.net headquarters garden.
Great Brown Drake
And we found this Great Brown Drake (Hexagenia bilineata), a large species of burrowing mayfly, clinging to our building’s masonry wall after last night’s early June nuptial flight.
Green June Bugs
So when can we expect to see Green June Bugs (Cotinis nitida) devouring our discarded watermelon rinds?  Probably not until July.

Last of the Season

For migrating birds, the spring season is drawing to a close.  The last of the Neotropical songbirds are now trickling through while the final waves of sandpipers and other shorebirds may have already cleared our region to continue their long journey north to breeding grounds in Canada and Alaska.  From earlier this week…

Semipalmated Plover
A northbound Semipalmated Plover during a stopover in the Lower Susquehanna River Watershed.  These smaller cousins of our local double-banded Killdeer are a tundra nesting species.
Semipalmated Plover and Least Sandpipers
A Semipalmated Plover and a small flock of Least Sandpipers feed and recharge on a mudflat.
A Semipalmated Sandpiper (left) and a Least Sandpiper.
A Semipalmated Sandpiper (left) and a Least Sandpiper during a migration break.  The latter species is on its way to taiga wetlands in Canada and Alaska to breed.  Like the Semipalmated Plover, the Semipalmated Sandpiper continues beyond the taiga regions to nest in the tundra of the far north.
Greater Yellowlegs
This Greater Yellowlegs needs to hustle if it’s going to reach the species’ nesting grounds in the taiga of Canada in time to participate in this year’s breeding cycle.  Otherwise, it may be among the early birds we see coming back south through our area as soon as late June, during the start of the fall migration.

You read it right.  “Fall migration” often gets going by the first day of summer—southbound birds, less than a month away!

Pest Control at the Picnic

During one of the interludes between yesterday’s series of thunderstorms and rain showers, we had a chance to visit a wooded picnic spot to devour a little snack.  Having packed lite fare, there wasn’t enough to share.  Fortunately, pest control wasn’t a concern.  It was handled for us…

American Toad
This young American Toad (Anaxyrus americanus) patrolled the grounds of the grove gobbling up any creepy crawlies it happened to encounter.
Big-headed Ant
Though spotted nearby, none of these traditional picnic crashers, possibly Big-headed Ants (Pheidole species), made it through the toad’s dragnet.
Eastern Black Carpenter Ant
What had this Eastern Black Carpenter Ant (Camponotus pennsylvanicus) so frustrated during its attempt to spoil our affair?
Eastern Black Carpenter Ant
The recycled plastic lumber picnic table left this party pooper with nothing to chew…
Decaying Tree Stump
…so it’s back to gnawing on this rotting stump for you!
Crab Spider
We spied this curious little Crab Spider (Tmarus species) searching the benches for tiny invertebrates.
Running Crab Spider
Then, at the corner of the table, we found this Running Crab Spider (Philodromus species) clutching what appeared to be two ofttimes pesky, but harmless, flying insects called non-biting midges (Chironomidae).
Running Crab Spider
Down the hatch!  Though smaller than your pinky fingernail, the Running Crab Spider is still an accomplished predator.

After enjoying our little luncheon and watching all the sideshows, it was time to cautiously make our way home,…

Snapping Turtle
…halting briefly to allow this Snapping Turtle a chance to cross the road.

Some Early Season Damselflies and Dragonflies

During recent weeks, as temperatures have warmed into the 70s and 80s, early season odonates—damselflies and dragonflies—have taken to the wing along our watercourses and wetlands to prey upon small flying insects.

Vegetated Stream
In addition to wetlands, many vegetated streams, ponds, lakes, and rivers are prime locations to find a variety of damselflies and dragonflies.
Common Whitetail and Eastern Amberwings
A male Common Whitetail (top) and some Eastern Amberwings (Perithemis tenera) patrol the edge of a verdant pond in search of small flying insects.  In addition to defending territories for hunting, many males will begin chasing off potential rivals as the breeding season gets underway.  Both of these dragonflies are tolerant of mud-bottomed waters during their aquatic larval stages of life and may be the only species found at places like farm ponds.
Male Fragile Forktail
The Fragile Forktail is common throughout the Lower Susquehanna River Watershed.  It is the most likely damselfly to colonize garden ponds, wet ditches, and other small bodies of water.
Female Fragile Forktail
Having just mated with the male seen in the previous image, this female Fragile Forktail prepares to oviposit (lay her eggs) among the submerged plant matter in the shallows of this pond.  After hatching, the larval damselflies will spend an entire year as aquatic predators before taking flight as adults next spring.
Male Blue Dasher
The Blue Dasher is a common dragonfly around streams, ponds, and wetlands.  It can frequently be found perched in sunny woodland clearings, even those quite a distance from their breeding area.
Male Eastern Forktail
The Eastern Forktail (Ischnura verticalis) is a common damselfly around almost any calm, vegetated waters.  They frequently perch on emergent plant leaves and stems.
Common Baskettail
The Common Baskettail (Epitheca cynosura) is currently numerous around tree-lined pond and lake shores.  They spend nearly all of their time on the wing and frequently dart in and out of the shade while hunting and defending their territory from other dragonflies.  Unless you happen to catch a quick glimpse of them in good sunlight, these hyperactive insects will appear completely black in color.
Common Baskettail
Another Common Baskettail, this one mostly lacking any black coloration on the base section of the hindwings.
Lancet Clubtail
The Lancet Clubtail is a handsome early season dragonfly of slow clear streams, ponds, and wetlands.  They spend much of their time perched, watching for prey.
Lancet Clubtail
We found this Lancet Clubtail about 100 yards from a mountain stream perched on the ground atop some debris on a seldom-traveled forest road,…
Lancet Clubtail
…and this one clinging to some shrubs along the shore of a clear woodland pond.

If you’re out and about in coming days, you’ll find that flights of Common Green Darners, Black Saddlebags, and other species are underway as well.  As the waters of the lower Susquehanna valley continue to warm, an even greater variety of these insects will take to the wing.  To help with the identification of those you see, be certain to click the “Damselflies and Dragonflies” tab at the top of this page.

Photo of the Day

Grasshopper Sparrow
A nesting Grasshopper Sparrow surveys the warm-season grasslands at Middle Creek Wildlife Management Area.  Minutes later, this evening’s thundershower sent everyone and everything seeking cover.

Arboreal Birds and Tent Caterpillars

During the past week, we’ve been exploring wooded slopes around the lower Susquehanna region in search of recently arrived Neotropical birds—particularly those migrants that are singing on breeding territories and will stay to nest.  Coincidentally, we noticed a good diversity of species in areas where tent caterpillar nests were apparent.

Eastern Tent Caterpillar Nest
The conspicuous nest of the Eastern Tent Caterpillar (Malacosoma americanum), a native species of moth.  The first instar of the larval caterpillars hatch in early spring from egg masses laid on the limbs of the host tree by an adult female moth during the previous spring.  Soon after they begin feeding on the host tree’s first tender shoots, these tiny, seldom-noticed larvae start communal construction of a silk tent to act as a shelter and greenhouse-like solar collector that will both provide protection from the elements and expedite their growth.
Eastern Tent Caterpillar
The familiar last instar of the Eastern Tent Caterpillar is the most consumptive stage of the animal’s life.  After feeding in the treetops, they will descend to the ground and seek a sheltered location to pupate.  Adult moths emerge in several weeks to take to the air, mate, and produce eggs to be deposited on a host tree for hatching next year.  The favorite host tree in forests of the Lower Susquehanna River Watershed: native Black Cherry.

Here’s a sample of the variety of Neotropical migrants we found in areas impacted by Eastern Tent Caterpillars.  All are arboreal insectivores, birds that feed among the foliage of trees and shrubs searching mostly for insects, their larvae, and their eggs.

Yellow-throated Vireo
The Yellow-throated Vireo nests, feeds, and spends the majority of its time feeding among canopy foliage.
Eastern Wood-Pewee
The Eastern Wood-Pewee is a flycatcher found in mature woodlands.  It feeds not only among the limbs and leaves, but is an aerial predator as well.
Northern Parula
The Northern Parula nests in mature forests along rivers and on mountainsides, particularly where mature trees are draped with thick vines.
Hooded Warbler
The Hooded Warbler (Setophaga citrina) is found among thick understory growth on forested slopes.
Ovenbird
The Ovenbird builds a domed, oven-like nest on the ground and forages in the canopy.
Kentucky Warbler
The Kentucky Warbler (Geothlypis formosa) nests in woodland undergrowth, often near steep, forested slopes.
Worm-eating Warbler
The Worm-eating Warbler (Helmitheros vermivorum) nests among woody understory growth on forested hillsides.
Scarlet Tanager
The Scarlet Tanager is often difficult to observe because of its affinity for the canopy of mature forest trees.

In the locations where these photographs were taken, ground-feeding birds, including those species that would normally be common in these habitats, were absent.  There were no Gray Catbirds, Carolina Wrens, American Robins or other thrushes seen or heard.  One might infer that the arboreal insectivorous birds chose to establish nesting territories where they did largely due to the presence of an abundance of tent caterpillars as a potential food source for their young.  That could very well be true—but consider timing.

Already Gone-  By the time Neotropical migrants arrive in our area, the larval stages of the Eastern Tent Caterpillar’s life cycle are already coming to an end.  The nests that these native insects constructed to capture the energy of the springtime sun have allowed the larvae to exit and browse foliage when conditions were suitable, then return for shelter when they were not.  While inside, the larvae could move among the chambers of their structure to find locations with a temperature that best suited their needs.  Therein the solar heating and communal warmth sped up digestion and growth.
Eastern Tent Caterpillar
Eastern Tent Caterpillar larvae are now in their bristly final-instar stage and the majority have already moved to the ground to each seek a place to pupate and metamorphose into an adult moth.  Arboreal Neotropical birds have scarcely had a chance to feed upon them, and ground-feeding species seem to lack any temptation.  As for the adult moths, they fly only at night and live for just one day, offering little in the way of food for aerial, arboreal, or ground-feeding birds.
Wild Turkey
Having left arboreal environs, Eastern Tent Caterpillar larvae are now food for ground-feeding birds like our resident Wild Turkeys.  They need only get past the bristly hairs on the caterpillar’s back and the foul taste that may result from its limited diet of cyanogenic Black Cherry leaves.
Yellow-billed Cuckoo
The arboreal Yellow-billed Cuckoo (seen here) and its close relative the Black-billed Cuckoo (Coccyzus erythropthalmus) are the two species of birds in our area known to regularly feed on bristly tent caterpillars.  But having just arrived from the tropics to nest, they’ll need to rely on other insects and their larvae as sources of food for their young.
Black Cherry defoliated by Eastern Tent Caterpillars.
Final-instar Eastern Tent Caterpillars often defoliate Black Cherry trees before moving to the ground to pupate. Their timing allows them to feed on the fresh foliage while it is still young and tender, and to largely avoid becoming food for the waves of Neotropical birds that arrive in the lower Susquehanna basin in May.

So why do we find this admirable variety of Neotropical bird species nesting in locations with tent caterpillars?  Perhaps it’s a matter of suitable topography, an appropriate variety of native trees and shrubs, and an attractive opening in the forest.

American Redstart
An American Redstart singing in a Black Cherry.  Unlike others in the vicinity, this tree nestled among several very large Eastern White Pines showed no signs of tent caterpillar activity.  It may be that for one reason or another, no adult female moth deposited her eggs on this particular tree.  During our visits, Black Cherry was but one of the diverse variety of native trees and shrubs found growing on the sloping topography that created attractive habitat for the nesting birds we found.  We happened to notice that a majority, but not all, of those Black Cherry trees were impacted by Eastern Tent Caterpillars.
Black Cherry in Flower
The end of the Eastern Tent Caterpillar’s larval surge may spell the end of their nests for the year, but it’s not the end for the Black Cherry and other host trees in the Prunus (cherry) and Malus (apple) genera.  Because it’s still early in the season, they have plenty of time to re-leaf and many will still flower and produce fruit.  Those flowers and foliage will attract numerous other insects (including pollinators) that benefit breeding birds.
Blue-winged Warbler
The Blue-winged Warbler inhabits shrubby breaks in the forest such as this utility right-of-way where Black Cherry trees have sprouted after their seeds arrived in waste deposited by fruit-eating (frugivorous) birds.  Already attractive to a variety of insectivores, these openings soon lure egg-laying Eastern Tent Caterpillar moths to the cherry trees growing therein.  Even in dense forest, a small clearing created by a cluster of dead trees makes good bird habitat and will sooner or later be visited by fruit-eating species that will inadvertently sow seeds of Black Cherry, starting yet another stand of host trees for Eastern Tent Caterpillars.  It’s the gap in the forest that often attracts the birds, some of which plant the host trees, which sometimes entice Eastern Tent Caterpillar moths to lay their eggs.
Red-Eyed Vireo
Adapt and Reuse-  A Red-eyed Vireo visits an Eastern Tent Caterpillar nest…
Red-eyed Vireo
…and ignores the few remaining occupants that could easily be seized to instead collect silk to reinforce its own nest.

Here in the Lower Susquehanna River Watershed, the presence of Eastern Tent Caterpillar nests can often be an indicator of a woodland opening, natural or man-made, that is being reforested by Black Cherry and other plants which improve the botanical richness of the site.  For numerous migratory Neotropical species seeking favorable places to nest and raise young, these regenerative areas and the forests surrounding them can be ideal habitat.  For us, they can be great places to see and hear colorful birds.

Scarlet Tanager
Our Lucky Break-  This Scarlet Tanager descended from the treetops to feed on spiders in a small forest clearing.

Photo of the Day

Paulownia in Flower
While in flower, this extensive stand of Princess Trees (Paulownia tomentosa) straddling Second Mountain north of Harrisburg might be mistaken for a series of boulder outcrops.  Native to eastern Asia, the fast-growing Princess Tree has escaped cultivation to become naturalized in many parts of eastern North America.  You’ll currently notice the showy purple blooms on many forested ridges and hilltops throughout the Lower Susquehanna River Watershed.  Paulownia tomentosa is also known as the Phoenix Tree, a name derived from its ability, due to its extensive root system, to regenerate following fire.  This fast-growing invasive therefore calls for measures in addition to prescribed burns for control within infected forests.  Mechanical and/or chemical methods of removal are frequently required.

See Food and an Oriole Doubleheader

The rain and clouds have at last departed.  With blue skies and sunshine to remind us just how wonderful a spring afternoon can be, we took a stroll at Memorial Lake State Park in Lebanon County, Pennsylvania, to look for some migratory birds.

Indigo Bunting
Though running just a few days later than usual, Indigo Buntings have arrived to begin nesting.
Common Loon
This Common Loon dropped by Memorial Lake during a storm several days ago and decided to stay awhile.  It’s a species that winters in oceanic waters along the Atlantic seaboard and nests on glacial lakes to our north.
Common Loon
Because of the low level of turbidity in Memorial Lake, visibility is good enough to allow this benthic feeder an opportunity to see food before expending energy to dive down and retrieve it.  Favorable foraging conditions might be part of the reason this bird is hanging around.
Shoreline Vegetation at Memorial Lake
Clear Water-  Memorial Lake is one of the few man-made lakes in the Lower Susquehanna River Watershed to be appropriately vegetated with an abundance of submerged, floating, and emergent plants.  As a result, the water from Indiantown Run that passes through the impoundment is minimally impacted by nutrient loads and the algal blooms they can cause.  Buffers of woody and herbaceous growth along the lake’s shorelines provide additional nutrient sequestering and help prevent soil erosion and siltation.
Baltimore Oriole
The breeding season has begun for Neotropical migrants including this Baltimore Oriole, which we found defending a nesting territory in a stand of Black Walnut trees.
Orchard Oriole
Along the edge of the lake, this Orchard Oriole and its mate were in yet another stand of tall walnut trees.
Common Nighthawks
Early in the season and early in the day, we started seeing Common Nighthawks flying above wooded areas north of the lake at 4 o’clock this afternoon.  After all the raw and inclement weather they’ve experienced in recent days, the warm afternoon was probably their first opportunity to feed on flying insects in quite a while.
Common Nighthawks
Early birds, Common Nighthawks feeding at 4 P.M.

What?  You thought we were gonna drop in on Maryland’s largest city for a couple of ball games and some oysters, clams, and crab cakes—not likely.

More Migrating Birds

As waves of wet weather persistently roll through the Lower Susquehanna River Watershed, the tide of northbound migrants continues.  Here are few of today’s highlights…

Eastern Kingbird
Though few in number several days ago, flycatchers are now quite common.  Many of the Eastern Kingbirds we’re now seeing will stay to nest in trees bordering grasslands and pastures.
Willow Flycatcher
Willow Flycatchers nest along streams and other bodies of water where herbaceous growth and scattered shrubs are plentiful.  Lacking favorable habitat, many will continue moving north in coming days.
Lincoln's Sparrow
The seldom seen Lincoln’s Sparrow likes wet thickets for layovers during its passage through the lower Susquehanna valley.  They are often the last of the migratory sparrows to transit the area in May.  These elusive birds nest primarily in boggy thickets far to the north of our region, mostly in Canada.
Northern Parula
Colorful warblers are still arriving.  Remember to watch for them in unusual places due to stormy weather.  Earlier today, we spotted this Northern Parula prowling a lakeside willow instead of spending its time among the crown foliage and vines adorning mature forest trees.  Breezy conditions ahead of an afternoon shower may have prompted this bird to seek caterpillars and other grub in this protected location.
Least and Solitary Sandpipers
As May churns on, more and more shorebirds will be moving through on their way to nesting grounds in the interior of Canada.  This flock of Least and Solitary Sandpipers was found on the muddy margins of a man-made pond.  Flooded portions of farm fields and stormwater basins are also good places to see these migrants as they trek north.

A Pre-dawn Thunderstorm and a Fallout of Migrating Birds

In recent days, the peak northbound push of migratory birds that includes the majority of our colorful Neotropical species has been slowed to a trickle by the presence of rain, fog, and low overcast throughout the Mid-Atlantic States.  Following sunset last evening, the nocturnal flight resumed—only to be grounded this morning during the pre-dawn hours by the west-to-east passage of a fast-moving line of strong thundershowers.  The NOAA/National Weather Service images that follow show the thunderstorms as well as returns created by thousands of migrating birds as they pass through the Doppler Radar coverage areas that surround the lower Susquehanna valley.

Sterling, Virginia, Doppler Radar west of Washington, D.C., at 4:00 A.M. E.D.T. indicates a dense flight of northbound migrating birds located just to the south of the approaching line of rain and thunderstorms over the State College, Pennsylvania, radar coverage area.  (NOAA/National Weather Service image)
More northbound birds are indicated at 4 A.M. by the radar station located at Dover, Delaware…  (NOAA/National Weather Service image)
…and by the Mount Holly, New Jersey, radar site.  (NOAA/National Weather Service image)
Many of the migrating birds shown here over the Binghamton, New York, radar station at 4 A.M. probably overflew the lower Susquehanna region earlier in the night.  (NOAA/National Weather Service image)
And these birds over Albany, New York’s, radar station at 4 A.M. are mostly migrants that passed north over New Jersey and easternmost Pennsylvania last evening and during the wee hours of this morning.  (NOAA/National Weather Service image)

Just after 4 A.M., flashes of lightning in rapid succession repeatedly illuminated the sky over susquehannawildlife.net headquarters.  Despite the rumbles of thunder and the din of noises typical for our urban setting, the call notes of nocturnal migrants could be heard as these birds descended in search of a suitable place to make landfall and seek shelter from the storm.  At least one Wood Thrush and a Swainson’s Thrush (Catharus ustulatus) were in the mix of species passing overhead.  A short time later at daybreak, a Great Crested Flycatcher was heard calling from a stand of nearby trees and a White-crowned Sparrow was seen in the garden searching for food.  None of these aforementioned birds is regular here at our little oasis, so it appears that a significant and abrupt fallout has occurred.

White-crowned Sparrow
A White-crowned Sparrow in the headquarters garden at daybreak.  It’s the first visit by this species in a decade or more.

Looks like a good day to take the camera for a walk.  Away we go!

Gray Catbird
Along woodland edges, in thickets, and in gardens, Gray Catbirds were everywhere today.  We heard and/or saw hundreds of them.
American Redstart
During our travels, American Redstarts were the most frequently encountered warbler.  Look for them in low-lying forested habitats.
Many early-arriving Baltimore Orioles have already begun building nests.  But widespread territorial fighting today may be an indication that some latecomer orioles became trespassers after dropping in on existing territories during the morning fallout.
Red-eyed Vireo
Red-eyed Vireos are difficult to see but easily heard in forested areas throughout the Lower Susquehanna River Watershed.
Scarlet Tanager
If the oriole isn’t the showiest of the Neotropical migrants, then the Scarlet Tanager is certainly a contender…
Scarlet Tanager
Listen for their burry, robin-like song in the treetops of mature upland forests.
Wood Thrush
No woodland chorus is complete without the flute-like harmony of the Wood Thrush.  Look and listen for them in rich forests with dense understory vegetation.
Eastern Wood-Pewee
The Eastern Wood-Pewee, another forest denizen, has an easy song to learn…a series of ascending “pee-a-wee” phrases interspersed with an occasional descending “pee-urr”.  It was one of the few flycatchers we found today, but more are certainly on the way.  Their numbers should peak in coming days.
Yellow-rumped Warbler
Yellow-rumped Warblers can be especially numerous during migration but tend to peak prior to the arrival of the bulk of the Neotropical species.  This was the only “yellow-rump” we encountered today.  The majority have already passed through on their way to breeding grounds to our north.
Common Yellowthroat
If today you were to visit a streamside thicket or any type of early successional habitat, you would probably find this perky little warbler there, the Common Yellowthroat.
Yellow Warbler
The Yellow Warbler likes streamside thickets too.  You can also find them along lakes, ponds, and wetlands, especially among shrubby willows and alders.
White-crowned Sparrow
While nowhere near the headquarters garden, we ran into another White-crowned Sparrow in less-than-ideal habitat.  This one was in a row of trees in a paved parking lot.
Bobolink
Not all songbirds migrate at night. The Bobolink is an example of a diurnal (day-flying) migrant.  They’re currently arriving in hay fields that are spared the mower until after nesting season.
Blue-gray Gnatcatcher
While looking for Neotropical species and other late-season migrants, we also found numerous early arrivals that had already begun their breeding cycles.  We discovered this Blue-gray Gnatcatcher on its nest in a Black Walnut tree…
Blue-gray Gnatcatcher
…then, later in the day, we found this one in its nest, again in a Black Walnut tree.  Note the freshly emerging set of leaves and flower clusters.  With many tree species already adorned in a full set of foliage, open canopies in stands of walnuts we found growing in reforested areas seemed to be good places to see lots of migrants and other birds today.  It’s hard to say whether birds were more numerous in these sections of woods or were just easier to observe among the sparse leaf cover.  In either case, the nut-burying squirrels that planted these groves did us and the birds a favor.

There’s obviously more spring migration to come, so do make an effort to visit an array of habitats during the coming weeks to see and hear the wide variety of birds, including the spectacular Neotropical species, that visit the Lower Susquehanna River Watershed each May.  You won’t regret it!

Wood Ducks
Wood Ducks arrived in February and March to breed in the lower Susquehanna valley.  Soon after hatching in April or May, the young leave the nest cavity to travel under the watchful gaze of their ever-vigilant mother as they search for food along our local waterways.  If you’re fortunate, you might catch a glimpse of a brood and hen while you’re out looking at the more than one hundred species of birds that occur in our region during the first half of May.  Good luck!

Sightings on a Beautiful Spring Morning

Following a frosty night, sunny skies and a south breeze brought lots of action to the headquarters garden this morning.  Take a look…

Mason Bee at nest box
Mason Bees are quickly depositing their eggs and a mixture of pollen and nectar called a “pollen loaf” within holes we drilled into blocks of wood in our bee houses.  Each egg is laid in its own chamber within which the larva will hatch, feed on “pollen loaf”, and mature.  The individual cells, including the outermost one in the hole, are sealed with partitions made of mud.  It’s just like a mason using mortar.  Early next spring, the new generation of adults will emerge to begin the process once again.
Black Vulture
This morning’s south wind helped propel some northbound raptors.  This Black Vulture was the first we’ve seen from the headquarters garden since last fall.  While Turkey Vultures remain common and roost nearby, Black Vulture are noticeably less numerous since being impacted by avian flu one year ago.
Cooper's Hawk
This Cooper’s Hawk is one of pair nesting somewhere nearby.  It was quickly gaining altitude on a thermal…
Cooper's Hawks tangle.
…to intercept a transient Cooper’s Hawk (upper right) which it promptly escorted away to the north.
Broad-winged Hawk
Back from their winter holiday in the tropics, migrating Broad-winged Hawks are returning to breed in the forests of the north.  Watch for them either singly or in small groups as they “kettle” in thermal updrafts above south-facing slopes and sun-drenched paved surfaces.
American Robin at Bird Bath
Many birds including this American Robin have been frequenting our water features.  Remember to keep your fixture clean and change the water at least daily.  Watch the temperature too.  A late season freeze can leave you with a shattered bird bath.

Photo of the Day

White-throated Sparrow
While generally common along forest edges throughout the lower Susquehanna valley from mid-autumn through mid-spring, we seldom see White-throated Sparrows in the urban oasis that is the susquehannawildlife.net headquarters garden.  Our greatest hope for spotting one comes during the peak times of seasonal migration.  Alas, gloomy weather grounded this handsome northbound chap for the past several days and at last gave us a chance to repeatedly hear his cheery “old sam peabody-peabody-peabody” song.

Solar Eclipse of 2024

It was dubbed the “Great Solar Eclipse”, the Great North American Eclipse”, and several other lofty names, but in the lower Susquehanna valley, where about 92% of totality was anticipated, the big show was nearly eclipsed by cloud cover.  With last week’s rains raising the waters of the river and inundating the moonscape of the Pothole Rocks at Conewago Falls, we didn’t have the option of repeating our eclipse observations of August, 2017, by going there to view this year’s event, so we settled for the next best thing—setting up in the susquehannawildlife.net headquarters garden.  So here it is, yesterday’s eclipse…

Solar Eclipse 2024
Here’s one of our first views through a break in the clouds as photographed using a number 12 welder’s glass to shield the camera.
Solar Eclipse 2024
A shot through the welder’s glass with minimal cloud cover reveals a sunspot (AR3628) visible at between ten and eleven o’clock on the solar surface.
Solar Eclipse 2024
Clouds aren’t necessarily a bad thing during a solar eclipse.  Putting the welding filter aside, we were able to photograph the sun directly, without risk of damage to the camera.  Again, sunspot AR3628 can be seen just off the limb of the moon at between ten and eleven o’clock.
Solar Eclipse 2024
It’s 3:21 P.M. E.D.T., and it’s about as good as it’s going to get.  Fortunately for us, the clouds are maximizing the effect.
Solar Eclipse 2024
The sky darkened dramatically as the moon obscured more than 90% of the sun’s disk. Looking toward the northwest, where observers in locations including Erie, Pennsylvania, were experiencing a total solar eclipse, the sky appeared almost night-like.
Solar Eclipse 2024
Here in the lower Susquehanna region, the clouds made our partial solar eclipse an eerie one.
Solar Radio Shutdown during Annular Solar Eclipse 2024
Our home-brew solar-powered radio shut down.
Mourning Dove cooing during solar eclipse.
Our male Mourning Dove perched above its nests site and began a premature evening chorus of sorrowful coos.
Fish Crow Returning to Roost during solar eclipse
The flock of Fish Crows that has been lingering in the area for several weeks was seen making their way to a small grove of nearby evergreens where they often spend the night.
Turkey Vulture Flapping Its Way to Roost during solar eclipse.
Since early winter, Turkey Vultures have been roosting at a site about a half mile from our headquarters.  Each evening, they can be seen leisurely riding the late afternoon thermals as they glide in to pass the night at their favored resting spot.  During the height of the eclipse, as clouds co-conspired to quickly darken the sky and diminish the thermal updrafts, our local vultures were making a hurried scramble, flapping madly to get back to their roost.
The Eclipse of 2024 Wanes
Within fifteen minutes, the cloud cover thinned and the moon started to slide away.  Rays of sunshine quickly renewed the pace of an early spring afternoon.  Soon, the bees were buzzing around, the crows were out looking for trash, and the vultures were piloting the skies in search of deadbeats.
Solar Eclipse 2024
The Great Eclipse of 2024 left us with a sunny smile.

Chesapeake Bay Maritime Accidents and Their Impact on Susquehanna Wildlife

Tuesday’s collision of the container ship Dali into Baltimore’s Francis Scott Key Bridge and the nearly immediate collapse of the span into the chilly waters below reminds us just how unforgiving and deadly maritime accidents can be.  Upon termination of rescue and recovery operations, salvage and cleanup will be prioritized as the next steps in the long-term process of reopening the navigable waters to ship traffic and construction of a new bridge.  Part of the effort will include monitoring for leaks of fuels and other hazardous materials from the ship, its damaged cargo containers, and vehicles and equipment that were on the bridge when it failed.

Damage to the hull of the Dali and to the cargo containers on her deck could lead to leaks of hazardous liquids or other materials into Chesapeake Bay.  (United States Army Corps of Engineers Baltimore image)

On the waters and shores of today’s Chesapeake, numerous county, state, and federal agencies, including the United States Coast Guard, monitor and inspect looking for conditions and situations that could lead to point-source or accidental discharges of petroleum products and other hazardous materials into the bay.  Many are trained, equipped, and organized for emergency response to contain and mitigate spills upon detection.  But this was not always the case.

Through much of the twentieth century, maritime spills of oil and other chemicals magnified the effects of routine discharges of hazardous materials and sanitary sewer effluent into the Chesapeake and its tributaries.  The cumulative effect of these pollutants progressively impaired fisheries and bay ecosystems leading to noticeable declines in numbers of many aquatic species.  Rather frequently, spills or discharges resulted in conspicuous fish and/or bird kills.

One of the worst spills occurred near the mouth of the Potomac River on February 2, 1976, when a barge carrying 250,000 gallons of number 6 oil sank in a storm and lost its cargo into the bay.  During a month-long cleanup, the United States Coast Guard recovered approximately 167,000 gallons of the spilled oil, the remainder dispersed into the environment.  A survey counted 8,469 “sea ducks” killed.  Of the total number, the great majority were Horned Grebes (4,347 or 51.3%) and Long-tailed Ducks (2,959 or 34.9%).  Other species included Surf Scoter (Melanitta perspicillata) (405 or 4.8%), Common Loon (195 or 2.3%), Bufflehead (166 or 2.0%), Ruddy Duck (107 or 1.3%), Common Goldeneye (78 or 0.9%), Tundra Swan (46 or 0.5%), Greater Scaup (19 or 0.2%), American Black Duck (12 or 0.2%), Common Merganser (11 or 0.1%), Canvasback (10 or 0.1%), Double-crested Cormorant (10 or 0.1%), Canada Goose (8 or 0.1%), White-winged Scoter (Melanitta deglandi) (7 or 0.1%), Redhead (5 or 0.1%), gull species (10 or 0.1%), miscellaneous ducks and herons (13 or 0.2%) and unidentified (61 or 0.7%).  During the spring migration, a majority of these birds would have made their way north and passed through the lower Susquehanna valley.  The accident certainly impacted the occurrence of the listed species during that spring in 1976, and possibly for a number of years after.

Horned Grebe during migration on the Susquehanna near Haldeman Riffles.
Of the 8,469 birds killed by the February 2, 1976, oil spill on the Chesapeake, 51.3% (4,347) were Horned Grebes.  Many of them would have migrated north through the Lower Susquehanna River Watershed during the coming spring.

The Federal Water Pollution Control Act Amendments of 1972, commonly known as the Clean Water Act, put teeth into the original FWCPCA of 1948 and began reversing the accumulation of pollutants in the bay and other bodies of water around the nation.  Additional amendments in 1977 and 1987 have strengthened protections and changed the culture of “dump-and-run” disposal and “dilution-is-the-solution” treatment of hazardous wastes.  During the late nineteen-seventies and early nineteen-eighties, emergency response teams and agencies began organizing to control and mitigate spill events.  The result has been a greater awareness and competency for handling accidental discharges of fuels and other chemicals into Chesapeake Bay and other waterways.  These improvements can help minimize the environmental impact of the Dali’s collision with the Francis Scott Key Bridge in Baltimore.

Hickory Shad
Oil spills and other pollution in the Chesapeake can impact populations of migratory fish including the anadromous Hickory Shad which are presently transiting the bay on their way to the waters of the Susquehanna below Conowingo Dam.

SOURCES

Roland, John V., Moore, Glenn E., and Bellanca, Michael A.  1977.  “The Chesapeake Bay Oil Spill—February 2, 1976: A Case History”.  International Oil Spill Conference Proceedings (1977).  1977 (1): 523-527.

Prescribed Fire: Controlled Burns for Forest and Non-forest Habitats

Homo sapiens owes much of its success as a species to an acquired knowledge of how to make, control, and utilize fire.  Using fire to convert the energy stored in combustible materials into light and heat has enabled humankind to expand its range throughout the globe.  Indeed, humans in their furless incomplete mammalian state may have never been able to expand their populations outside of tropical latitudes without mastery of fire.  It is fire that has enabled man to exploit more of the earth’s resources than any other species.  From cooking otherwise unpalatable foods to powering the modern industrial society, fire has set man apart from the rest of the natural world.

In our modern civilizations, we generally look at the unplanned outbreak of fire as a catastrophe requiring our immediate intercession.  A building fire, for example, is extinguished as quickly as possible to save lives and property.  And fires detected in fields, brush, and woodlands are promptly controlled to prevent their exponential growth.  But has fire gone to our heads?  Do we have an anthropocentric view of fire?  Aren’t there naturally occurring fires that are essential to the health of some of the world’s ecosystems?  And to our own safety?  Indeed there are.  And many species and the ecosystems they inhabit rely on the periodic occurrence of fire to maintain their health and vigor.

For the war effort- The campaign to reduce the frequency of forest fires got its start during World War II with distribution of this poster in 1942.  The goal was to protect the nation’s timber resources from accidental or malicious loss due to fire caused by man-made ignition sources.  The release of the Walt Disney film “Bambi” during the same year and the adoption of the Smokey the Bear mascot in 1944 softened the message’s delivery, but the public relations outreach continued to be a key element of a no-fire policy to save trees for lumber.  Protection and management of healthy forest ecosystems in their entirety has only recently become a priority.  (National Archives image)

Man has been availed of the direct benefits of fire for possibly 40,000 years or more.  Here in the Lower Susquehanna River Watershed, the earliest humans arrived as early as 12,000 years ago—already possessing skills for using fire.  Native plants and animals on the other hand, have been part of the ever-changing mix of ecosystems found here for a much longer period of time—millions to tens of millions of years.  Many terrestrial native species are adapted to the periodic occurrence of fire.  Some, in fact, require it.  Most upland ecosystems need an occasional dose of fire, usually ignited by lightning (though volcanism and incoming cosmic projectiles are rare possibilities), to regenerate vegetation, release nutrients, and maintain certain non-climax habitat types.

But much of our region has been deprived of natural-type fires since the time of the clearcutting of the virgin forests during the eighteenth and nineteenth centuries.  This absence of a natural fire cycle has contributed to degradation and/or elimination of many forest and non-forest habitats.  Without fire, a dangerous stockpile of combustible debris has been collecting, season after season, in some areas for a hundred years or more.  Lacking periodic fires or sufficient moisture to sustain prompt decomposition of dead material, wildlands can accumulate enough leaf litter, thatch, dry brush, tinder, and fallen wood to fuel monumentally large forest fires—fires similar to those recently engulfing some areas of the American west.  So elimination of natural fire isn’t just a problem for native plants and animals, its a potential problem for humans as well.

Indiangrass on Fire
Indiangrass (seen here), Switchgrass, Big Bluestem, and Little Bluestem are native species requiring periodic forms of disturbance to eliminate competition by woody plants.  These warm-season grasses develop roots that penetrate deep into the soil, sometimes to depths of six feet or more, allowing them to survive severe drought and flash fire events.  In the tall grass prairies, these extensive root systems allow these grasses to return following heavy grazing by roaming herds of American Bison (Bison bison).  Without these habitat disturbances, warm season grasslands succumb to succession in about seven years.  With their periodic occurrence, the plants thrive and provide excellent wildlife habitat, erosion control, and grazing forage.

To address the habitat ailments caused by a lack of natural fires, federal, state, and local conservation agencies are adopting the practice of “prescribed fire” as a treatment to restore ecosystem health.  A prescribed fire is a controlled burn specifically planned to correct one or more vegetative management problems on a given parcel of land.  In the Lower Susquehanna River Watershed, prescribed fire is used to…

      • Eliminate dangerous accumulations of combustible fuels in woodlands.
      • Reduce accumulations of dead plant material that may harbor disease.
      • Provide top kill to promote oak regeneration.
      • Regenerate other targeted species of trees, wildflowers, grasses, and vegetation.
      • Kill non-native plants and promote growth of native plants.
      • Prevent succession.
      • Remove woody growth and thatch from grasslands.
      • Promote fire tolerant species of plants and animals.
      • Create, enhance, and/or manage specialized habitats.
      • Improve habitat for rare species (Regal Fritillary, etc.)
      • Recycle nutrients and minerals contained in dead plant material.

Let’s look at some examples of prescribed fire being implemented right here in our own neighborhood…

Prescribed Fire
Prescribed fires are typically planned for the dormant season extending from late fall into early spring with burns best conducted on days when the relative humidity is low.
Prescribed Fire at Fort Indiantown Gap
Prescribed fire is used regularly at Fort Indiantown Gap Military Reservation in Lebanon County, Pennsylvania, to keep accumulations of woody and herbaceous fuels from accumulating on and around the training range areas where live ordinance and other sources of ignition could otherwise spark large, hard-to-control wildfires.
Prescribed Fire at Fort Indiantown Gap
Prescribed fires replace the periodic natural burns that would normally reduce the fuel load in forested areas.  Where these fuels are allowed to accumulate, south-facing slopes are particularly susceptible to extreme fires due to their exposure to the drying effects of intense sunlight for much of the year.  The majority of small oaks subjected to treatment by the prescribed fire shown here will have the chance to regenerate without immediate competition from other species including invasive plants.  The larger trees are mostly unaffected by the quick exposure to the flames.  Note too that these fires don’t completely burn everything on the forest floor, they burn that which is most combustible.  There are still plenty of fallen logs for salamanders, skinks, and other animals to live beneath and within.

 

Prescribed fire in grassland.
A prescribed fire in late winter prevents this grassland consisting of Big Bluestem and native wildflowers from being overtaken by woody growth and invasive species.  Fires such as this that are intended to interrupt the process of succession are repeated at least every three to five years.
Prescribed Fire to Control Invasive Species
In its wildlife food plots, prescribed fire is used by the Pennsylvania Game Commission to prevent succession and control invasive species such as Multiflora Rose, instead promoting the growth of native plants.
A woodlot understory choked with combustible fuels and tangles of invasive Multiflora Rose.
An example of a woodlot understory choked with combustible fuels and dense tangles of invasive Multiflora Rose.  A forester has the option of prescribing a dose of dormant-season fire for a site like this to reduce the fuel load, top kill non-native vegetation, and regenerate native plants.
Precribed Fire to Eliminate Woody Growth
A dose of prescribed fire was administered on this grassland to kill the woody growth of small trees beginning to overtake the habitat by succession.
Precribed Fire Education Sign at middle creek Wildlife Management Area
The Pennsylvania Game Commission employs prescribed fire at Middle Creek Wildlife Management Area and on many of their other holdings to maintain grasslands.
Prescribed fire is used to eliminate invasive species including Multiflora Rose from grasslands at Middle Creek W.M.A.  Annual burns on the property are conducted in a mosaic pattern so that each individual area of the grassland is exposed to the effects of fire only once every two to five years.  Without fire or some type of mechanical or chemical intervention, succession by woody trees and shrubs would take hold after about seven years.
Prescribed fire is planned for a fraction of total grassland acreage at Middle Creek W.M.A. each year.  Another section of the mosaic is targeted in the following year and yet another in the year that follows that.  Because burns are conducted in the spring, grassland cover is available for wildlife throughout the winter.  And because each year’s fire burns only a portion of the total grassland acreage, wildlife still has plenty of standing grass in which to take shelter during and after the prescribed fire.
Grasshopper Sparrow
Prescribed fire at Middle Creek W.M.A. provides grassland habitat for dozens of species of birds and mammals including the not-so-common Grasshopper Sparrow…
Ring-necked Pheasant
…and stocked Ring-necked Pheasants that do nest and raise young there.
Prescribed Burn Maintains Savanna-like Habitat
On a few sites in the Lower Susquehanna River Watershed , prescribed fire is being used to establish and maintain savanna-like grasslands.  This one, located on a dry, south-facing slope near numerous man-made sources of ignition, can easily be dosed with periodic prescribed burns to both prevent succession and reduce fuel accumulations that may lead to a devastating extreme fire.
Pitch Pines in Savanna-like Habitat
One year following a prescribed burn, this is the autumn appearance of a savanna-like habitat with fire-tolerant Pitch Pine (Pinus rigida), Bear Oak, warm-season grasses, and a variety of nectar-producing wildflowers for pollinators.  These ecosystems are magnets for wildlife and may prove to be a manageable fit on sun-drenched sites adjacent to man-made land disturbances and their sources of ignition.
Red-headed Woodpecker Adult and Juvenile
Savanna-like grasslands with oaks and other scattered large trees, some of them dead, make attractive nesting habitat for the uncommon Red-headed Woodpecker.
Wild Turkey in Savanna-like Habitat
Prescribed fire can benefit hungry Wild Turkeys by maintaining savanna-like grasslands for an abundance of grasshoppers and other insects in summer and improving the success of mast-producing oaks for winter.
Buck Moth
In the Lower Susquehanna River Watershed, the caterpillar of the rare Eastern Buck Moth feeds on the foliage of the Bear Oak, also known as the Scrub Oak, a shrubby species that relies upon periodic fire to eliminate competition from larger trees in its early successional habitat.
Leaves of the Bear Oak in fall.
Leaves of the Bear Oak in fall.  The Bear Oak regenerates readily from top kill caused by fire.
Reed Canary Grass
Reed Canary Grass (Phalaris arundinacea) is a native cool-season grass with a colorful inflorescence in spring.  But given the right situation, it can aggressively overtake other species to create a pure stand lacking biodiversity.  It is one of the few native species which is sometimes labelled “invasive”.
Prescribed Burn to Reduce Prevalence of Reed Canary Grass
Prescribed fire can be used to reduce an overabundance of Reed Canary Grass and its thatch in wetlands.  Periodic burning can help restore species diversity in these habitats for plants and animals including rare species such as the endangered Bog Turtle (Glyptemys muhlenbergii).
On the range areas at Fort Indiantown Gap in Lebanon County, Pennsylvania, disturbances by armored vehicles mimic the effects of large mammals such as the American Bison which periodically trampled grasses to prevent succession and the establishment of woody plants on its prairie habitat.  To supplement the activity of the heavy vehicles and to provide suitable habitat for the very rare Regal Fritillary (Speyeria idalia) butterflies found there, prescribed fire is periodically employed to maintain the grasslands on the range.  These burns are planned to encourage the growth of “Fort Indiantown Gap Little Bluestem” grass as well as the violets used as host plants by the Regal Fritillary caterpillars.  These fires also promote growth of a variety of native summer-blooming wildflowers to provide nectar for the adults butterflies.
Depiction of Pennsylvania's Last American Bison, Killed in Union County in 1801. (Exhibit: State Museum of Pennsylvania, Harrisburg)
A last record of a wild American Bison killed in Pennsylvania was an animal taken in the Susquehanna watershed in Union County in 1801.  The species is thereafter considered extirpated from the state.  Since that time, natural disturbances needed to regenerate warm-season grasses have been limited primarily to fires and riverine ice scour.  The waning occurrence of both has reduced the range of these grasses and their prairie-like ecosystems in the commonwealth.  (Exhibit: State Museum of Pennsylvania, Harrisburg)
A male Regal Fritillary on the range at Fort Indiantown Gap, where armored vehicles and prescribed fire provide suitable prairie-like habitat for this vulnerable species.
Honey Bee Collecting Minerals After Prescribed Burn
Prescribed fires return the nutrients and minerals contained in dead plant material to the soil.  Following these controlled burns, insects like this Honey Bee can often be seen collecting minerals from the ashes.
Fly Collecting Minerals from Burned Grasses
A Greenbottle Fly gathering minerals from the ash following a prescribed burn.

In Pennsylvania, state law provides landowners and crews conducting prescribed fire burns with reduced legal liability when the latter meet certain educational, planning, and operational requirements.  This law may help encourage more widespread application of prescribed fire in the state’s forests and other ecosystems where essential periodic fire has been absent for so very long.  Currently in the Lower Susquehanna River Watershed, prescribed fire is most frequently being employed by state agencies on state lands—in particular, the Department of Conservation and Natural Resources on State Forests and the Pennsylvania Game Commission on State Game Lands.  Prescribed fire is also part of the vegetation management plan at Fort Indiantown Gap Military Reservation and on the land holdings of the Hershey Trust.  Visitors to the nearby Gettysburg National Military Park will also notice prescribed fire being used to maintain the grassland restorations there.

For crews administering prescribed fire burns, late March and early April are a busy time.  The relative humidity is often at its lowest level of the year, so the probability of ignition of previous years’ growth is generally at its best.  We visited with a crew administering a prescribed fire at Middle Creek Wildlife Management Area last week.  Have a look…

Members of a Pennsylvania Game Commission burn crew provide visitors to Middle Creek Wildlife Management Area with an overview of prescribed fire.
Members of a Pennsylvania Game Commission burn crew provide visitors to Middle Creek Wildlife Management Area with an overview of prescribed fire and the equipment and techniques they use to conduct a burn.
Burn Boss Checking Weather
Pennsylvania Game Commission Southeast Region Forester Andy Weaver will fulfill the role of Burn Boss for administering this day’s dose of fire.  His responsibilities include assessing the weather before the burn and calculating a probability of ignition.
Burn Boss Briefing Crew
The Burn Boss briefs personnel with information on site layout, water supply location(s), places of refuge, emergency procedures, the event’s goals and plan of action, crew assignments, and the results of the weather check: wind from the northwest at 5 miles per hour, temperature 48 degrees, and the relative humidity 63%. Today’s patient is a parcel of warm-season grasses receiving a dose of fire to eliminate invasive non-native plants, woody growth, and thatch.  The probability of ignition is 20%, but improving by the minute.
Prescribed Fire Test Burn
To begin the burn, a test fire is started in the downwind corner of the parcel, which also happens to be the bottom of the slope.  Fuel ignition is good.  The burn can proceed.
Igniting the Fire
Crews proceed uphill from the location of the test fire while igniting combustibles along both flanks of the area being treated.
Prescribed Fire Crew Member with Equipment
A drip torch is used to ignite the dried stems and leaves of warm-season grasses and wildflowers.  Each member of the burn crew wears Nomex fire-resistant clothing and carries safety equipment including a two-way radio, a hydration pack, and a cocoon-like emergency fire shelter.
Wildfire ATV
An all-terrain vehicle equipped with various tools, a fire pump, hose, and a small water tank accompanies the crew on each flank of the fire.
Prescribed Fire
A mowed strip of cool-season grasses along the perimeter of the burn area is already green and functions as an ideal fire break.  While the drip torch is perfect for lighting combustibles along the fire’s perimeter, the paintball gun-looking device is an effective tool used to lob incendiaries into the center areas of the burn zone for ignition.
Effective Fire Break
With green cool-season grasses already growing on the trails surrounding the burn zone, very little water was used to contain this prescribed fire.  Where such convenient fire breaks don’t already exist, crews carry tools including chain saws, shovels, and leaf blowers to create their own.  They also carry flame swatters, backpack water pumps, shovels, and other tools to extinguish fires if necessary.  None of these items were needed to control this particular fire.
Halting the Process of Succession in a Grassland with Prescribed Fire
This fast-burning fire provides enough heat to damage the cambium layer of the woody tree and shrub saplings in this parcel being maintained as a grassland/wildflower plot, thus the process of succession is forestalled.  Burns conducted during previous years on this and adjacent fields have also controlled aggressive growth of invasive Multiflora Rose and Olives (Elaeagnus species).
Containing the Fire on the Flanks
Crews proceed up the slope while maintaining the perimeter by igniting dry plant material along the flanks of the burn zone.
The Crew Monitors the Burn
Ignition complete, the crews monitor the fire.
Prescribed Fire: Natural Mosaic-style Burn Pattern
The Burn Boss surveys the final stages of a safe and successful prescribed fire.  The fire has left behind a mosaic of burned and unburned areas, just as a naturally occurring event may have done.  Wildlife dodging the flames may be taking refuge in the standing grasses, so there is no remedial attempt to go back and ignite these areas.  They’ll be burned during prescribed fires in coming years.
Great Spangled Fritillary
By June, this grassland will again be lush and green with warm-season grasses and blooming wildflowers like this Common Milkweed being visited by a Great Spangled Fritillary.
Eastern Tiger Swallowtails on Joe-pye Weed.
And later in the summer, Eastern Tiger Swallowtails on Joe-pye Weed.
Indiangrass in flower in mid-summer.
Indiangrass in flower in mid-summer.
Bobolinks in Indiangrass
Bobolinks glow in the late August sun while taking flight from a stand of warm-season grasses maintained using springtime prescribed fire.  The small dots on the dark background at the top of the image are multitudes of flying insects, many of them pollinators.  The vegetation is predominately Indiangrass, excellent winter cover for birds, mammals, and other wildlife.

Prescribed burns aren’t a cure-all for what ails a troubled forest or other ecosystem, but they can be an effective remedy for deficiencies caused by a lack of periodic episodes of naturally occurring fire.  They are an important option for modern foresters, wildlife managers, and other conservationists.

Another Big Flight of Geese and Swans

Yet another flight of waterfowl departing Chesapeake Bay for breeding grounds to our north passed over sections of the lower Susquehanna valley this morning.  In the one hour between 10 A.M. and 11 A.M., at least six thousand honking Canada Geese passed through the small piece of sky visible from susquehannawildlife.net headquarters.  At times, five or more flocks of about one hundred birds each were seen simultaneously.

Canada Geese
Northbound migratory Canada Geese pass over susquehannawildlife.net headquarters.
Canada Geese
While observing and photographing geese flying about two thousand feet above our heads, we noticed several barely visible flocks at much higher altitudes.  Any such birds flying above this flock would go undetected in or above the cumulus clouds.
Canada Geese
More geese on the way through.
Tundra Swans
In addition to the geese, a flock of 80 Tundra Swans was seen.  Not bad.

Snow Geese, Bald Eagles, and More at Middle Creek Wildlife Management Area

To take advantage of this unusually mild late-winter day, observers arrived by the thousands to have a look at an even greater number of migratory birds gathered at the Pennsylvania Game Commission’s Middle Creek Wildlife Management Area.  Here are some highlights…

Trails at Middle creek Wildlife Management Area
Multitudes of Sunday hikers enjoyed the warm afternoon on Middle Creek’s many trails.
Painted Turtles
In one of Middle Creek’s numerous impoundments, newly emerged Painted Turtles bask in the sunshine.
Brown-headed Cowbird
Native blackbirds, particularly males including this Brown-headed Cowbird, are arriving to stake out a claim on suitable breeding territory.
Red-winged Blackbirds
Male Red-winged Blackbirds visit the feeding station at the Middle Creek W.M.A. Visitor’s Center.
Brown-headed Cowbird and Red-winged Blackbird
Brown-headed Cowbirds regularly maintain close association with Red-winged Blackbirds, a frequent victim of the former’s nest parasitism, the practice of laying and abandoning their eggs in a host species’ abode.  By early May, adult “red-wings” can often be seen tending fledged cowbird young raised at the expense of their own progeny.
Common Grackles displaying.
Male Common Grackles display their colors in an attempt to establish dominance.
White-crowned Sparrow
Visitor’s to Middle Creek’s Willow Point Trail not only had a chance to see thousands of geese and other waterfowl, but they might also get a good look at some of the handsome White-crowned Sparrows that have been there during recent weeks.
Tree Swallow
The first Tree Swallows of the season have arrived to stake a claim to nest boxes located throughout the refuge’s grasslands.
Killdeer
Bare croplands and muddy shorelines around Middle Creek’s lakes and ponds are attracting migrating Killdeer.  Some will stay to nest.
Ring-billed Gulls
Hundreds of Ring-billed Gulls arrived during the late afternoon to spend the night on the main lake.
Red-tailed Hawk
A Red-tailed Hawk was seen hunting mice and exhibiting territorial behavior.  It is probably protecting a nest site somewhere on the refuge.
Canada Geese
Canada Geese could be seen coming and going, with migratory birds apparently supplementing the resident flock.  This group flushed when a Bald Eagle passed close by.
Bald Eagles
You could hold a Bald Eagle I.D. clinic at Middle Creek W.M.A. right now.  Dozens of birds of varying age classes could be seen in the trees surrounding the main lake and the larger ponds.  Currently, fifty or more could be present.  At least one Golden Eagle has been seen as well.
Adult Bald Eagle
An adult Bald Eagle in definitive plumage investigating the inhabitants of the lake.
Second-year Bald Eagle
This Bald Eagle in its second calendar year is not yet one year of age, but it has already begun replacing dark body feathers with a light plumage that will earn it the nickname “white belly” for this and its third year.  It will start molting its long hatch-year (juvenile) flight feathers soon after its first birthday.
Second-year Bald Eagle and Red-tailed Hawk
Another second-year immature Bald Eagle, this one being scolded by the aforementioned territorial Red-tailed Hawk.  Though showing some wear in the tail, this eagle still has a full set of lengthy hatch-year (juvenile) flight feathers and remains mostly dark below when compared to the bird of the same age class seen in the previous image.  As in other birds, diet, genetics, stress, climatic conditions, and many other factors will frequently vary the timing of molt among individuals in a population of Bald Eagles.
Third-year Bald Eagle
An immature Bald Eagle in its third calendar year still retaining numerous long juvenile wing and tail feathers.   In coming months, as it reaches its second birthday, it will begin replacing the remaining older plumage with a set of new flight feathers.
Fourth-year Bald Eagle
An immature Bald Eagle in its fourth calendar year approaches its third birthday with a rather conspicuous long juvenile feather remaining in each wing.  These feathers will soon be replaced.  In addition, the body plumage will darken, the head will begin to show more white, and the bill will become yellow.  In about two more years, the bird will attain its familiar adult definitive plumage.  Click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page to learn more about determining the age of these and other birds of prey.
Snow Geese and Observers at Middle Creek W.M.A.
Bald Eagles draw a crowd, but the real attraction at Middle Creek W.M.A. in late winter is Snow Geese,…
Snow Geese
…thousands of them.
Snow geese at Middle Creek W.M.A.
Migratory Snow Geese, an annual spectacle at Middle Creek.
Snow Geese and hundreds of onlookers.
Snow Geese and hundreds of delighted onlookers.

Snow Geese at M.C.W.M.A.

Snow geese at Middle Creek W.M.A.
The late afternoon sky filled with Snow Geese.
Short-eared Owl at M.C.W.M.A.
As daylight waned and the Snow Geese returned to the main lake for the night, more than one hundred lucky observers were treated to the rare sight of several Short-eared Owls (Asio flammeus) emerging to hunt the refuge’s managed grasslands for mice and voles.  For many of these visitors, it was a memorable first-time experience.

Waterfowl on a Rainy Day

Though soggy, windy, and rainy, it happened to be a delightfully mild day to search for migrating waterfowl in the Lower Susquehanna River Watershed.  Here’s a look at what we found temporarily grounded by the poor flight conditions…

Northern Pintails
It’s prime time for northbound Northern Pintails.
American Wigeons and Ring-necked Ducks
This raft of distant waterfowl appears to include mostly American Wigeons and Ring-necked Ducks.
Ring-necked Duck
A much more cooperative drake Ring-necked Duck.
American Black Ducks
A couple of American Black Ducks take a break during an afternoon shower.
Northern Shovelers
A pair of Northern Shovelers in the rain.
Common Mergansers
And a pair of blissful Common Mergansers.
Common Mergansers
Uh oh!…must be something he said.