Monarch an Endangered Species: What You Can Do Right Now

This month, the International Union for Conservation of Nature (I.U.C.N.) added the Migratory Monarch Butterfly (Danaus plexippus plexippus) to its “Red List of Threatened Species”, classifying it as endangered.  Perhaps there is no better time than the present to have a look at the virtues of replacing areas of mowed and manicured grass with a wildflower garden or meadow that provides essential breeding and feeding habitat for Monarchs and hundreds of other species of animals.

Monarch on Common Milkweed Flower Cluster
A recently arrived Monarch visits a cluster of fragrant Common Milkweed flowers in the garden at the susquehannawildlife.net headquarters.  Milkweeds included among a wide variety of plants in a garden or meadow habitat can help local populations of Monarchs increase their numbers before the autumn flights to wintering grounds commence in the fall.  Female Monarchs lay their eggs on milkweed leaves, then, after hatching, the larvae (caterpillars) feed on them before pupating.

If you’re not quite sure about finally breaking the ties that bind you to the cult of lawn manicuring, then compare the attributes of a parcel maintained as mowed grass with those of a space planted as a wildflower garden or meadow.  In our example we’ve mixed native warm season grasses with the wildflowers and thrown in a couple of Eastern Red Cedars to create a more authentic early successional habitat.

Comparison of Mowed Grass to Wildflower Meadow
* Particularly when native warm-season grasses are included (root depth 6′-8′)

Still not ready to take the leap.  Think about this: once established, the wildflower planting can be maintained without the use of herbicides or insecticides.  There’ll be no pesticide residues leaching into the soil or running off during downpours.  Yes friends, it doesn’t matter whether you’re using a private well or a community system, a wildflower meadow is an asset to your water supply.  Not only is it free of man-made chemicals, but it also provides stormwater retention to recharge the aquifer by holding precipitation on site and guiding it into the ground.  Mowed grass on the other hand, particularly when situated on steep slopes or when the ground is frozen or dry, does little to stop or slow the sheet runoff that floods and pollutes streams during heavy rains.

What if I told you that for less than fifty bucks, you could start a wildflower garden covering 1,000 square feet of space?  That’s a nice plot 25′ x 40′ or a strip 10′ wide and 100′ long along a driveway, field margin, roadside, property line, swale, or stream.  All you need to do is cast seed evenly across bare soil in a sunny location and you’ll soon have a spectacular wildflower garden.  Here at the susquehannawildllife.net headquarters we don’t have that much space, so we just cast the seed along the margins of the driveway and around established trees and shrubs.  Look what we get for pennies a plant…

Wildflower Garden
Some of the wildflowers and warm-season grasses grown from scattered seed in the susquehannawildlife.net headquarters garden.

Here’s a closer look…

Lance-leaved Coreopsis
Lance-leaved Coreopsis (Coreopsis lanceolata), a perennial.
Black-eyed Susan
Black-eyed Susan, a biennial or short-lived perennial.
Black-eyed Susan "Gloriosa Daisy"
“Gloriosa Daisy”, a variety of Black-eyed Susan, a biennial or short-lived perennial.
Purple Coneflower
Purple Coneflower, an excellent perennial for pollinators.  The ripe seeds provide food for American Goldfinches.
Common Sunflower
A short variety of Common Sunflower, an annual and a source of free bird seed.
Common Sunflower
Another short variety of Common Sunflower, an annual.

All this and best of all, we never need to mow.

Around the garden, we’ve used a northeast wildflower mix from American Meadows.  It’s a blend of annuals and perennials that’s easy to grow.  On their website, you’ll find seeds for individual species as well as mixes and instructions for planting and maintaining your wildflower garden.  They even have a mix specifically formulated for hummingbirds and butterflies.

Annuals in bloom
When planted in spring and early summer, annuals included in a wildflower mix will provide vibrant color during the first year.  Many varieties will self-seed to supplement the display provided by biennials and perennials in subsequent years.
Wildflower Seed Mix
A northeast wildflower mix from American Meadows.  There are no fillers.  One pound of pure live seed easily plants 1,000 square feet.

Nothing does more to promote the spread and abundance of non-native plants, including invasive species, than repetitive mowing.  One of the big advantages of planting a wildflower garden or meadow is the opportunity to promote the growth of a community of diverse native plants on your property.  A single mowing is done only during the dormant season to reseed annuals and to maintain the meadow in an early successional stage—preventing reversion to forest.

For wildflower mixes containing native species, including ecotypes from locations in and near the Lower Susquehanna River Watershed, nobody beats Ernst Conservation Seeds of Meadville, Pennsylvania.  Their selection of grass and wildflower seed mixes could keep you planting new projects for a lifetime.  They craft blends for specific regions, states, physiographic provinces, habitats, soils, and uses.  Check out these examples of some of the scores of mixes offered at Ernst Conservation Seeds

      • Pipeline Mixes
      • Pasture, Grazing, and Hay Mixes
      • Cover Crops
      • Pondside Mixes
      • Warm-season Grass Mixes
      • Retention Basin Mixes
      • Wildlife Mixes
      • Pollinator Mixes
      • Wetland Mixes
      • Floodplain and Riparian Buffer Mixes
      • Rain Garden Mixes
      • Steep Slope Mixes
      • Solar Farm Mixes
      • Strip Mine Reclamation Mixes

We’ve used their “Showy Northeast Native Wildflower and Grass Mix” on streambank renewal projects with great success.  For Monarchs, we really recommend the “Butterfly and Hummingbird Garden Mix”.  It includes many of the species pictured above plus “Fort Indiantown Gap” Little Bluestem, a warm-season grass native to Lebanon County, Pennsylvania, and milkweeds (Asclepias), which are not included in their northeast native wildflower blends.  More than a dozen of the flowers and grasses currently included in this mix are derived from Pennsylvania ecotypes, so you can expect them to thrive in the Lower Susquehanna River Watershed.

Swamp Milkweed
Swamp Milkweed, a perennial species, is included in the Ernst Seed “Butterfly and Hummingbird Garden Mix”.  It is a favorite of female Monarchs seeking a location to deposit eggs.
Monarch Caterpillar feeding on Swamp Milkweed
A Monarch larva (caterpillar) feeding on Swamp Milkweed.
Butterfly Weed
Butterfly Weed (Asclepias tuberosa) is included in the Ernst Seed “Butterfly and Hummingbird Garden Mix”.  This perennial is also known as Butterfly Milkweed.
Tiger Swallowtails visiting Butterfly Weed
Eastern Tiger Swallowtails are among the dozens of species of pollinators that will visit Butterfly Weed.

In addition to the milkweeds, you’ll find these attractive plants included in Ernst Conservation Seed’s “Butterfly and Hummingbird Garden Mix”, as well as in some of their other blends.

Wild Bergamot
The perennial Wild Bergamot, also known as Bee Balm, is an excellent pollinator plant, and the tubular flowers are a favorite of hummingbirds.
Oxeye
Oxeye is adorned with showy clusters of sunflower-like blooms in mid-summer.  It is a perennial plant.
Plains Coreopsis
Plains Coreopsis (Coreopsis tinctoria), also known as Plains Tickseed, is a versatile annual that can survive occasional flooding as well as drought.
Gray-headed Coneflower
Gray-headed Coneflower (Ratibida pinnata), a tall perennial, is spectacular during its long flowering season.
Monarch on goldenrod.
Goldenrods are a favorite nectar plant for migrating Monarchs in autumn.  They seldom need to be sown into a wildflower garden; the seeds of local species usually arrive on the wind.  They are included in the “Butterfly and Hummingbird Garden Mix” from Ernst Conservation Seeds in low dose, just in case the wind doesn’t bring anything your way.
Partridge Pea
Is something missing from your seed mix?  You can purchase individual species from the selections available at American Meadows and Ernst Conservation Seeds.  Partridge Pea is a good native annual to add.  It is a host plant for the Cloudless Sulphur butterfly and hummingbirds will often visit the flowers.  It does really well in sandy soils.
Indiangrass in flower.
Indiangrass is a warm-season species that makes a great addition to any wildflower meadow mix.  Its deep roots make it resistant to drought and ideal for preventing erosion.

Why not give the Monarchs and other wildlife living around you a little help?  Plant a wildflower garden or meadow.  It’s so easy, a child can do it.

Planting a riparian buffer with wildflowers and warm-season grasses
Volunteers sow a riparian buffer on a recontoured stream bank using wildflower and warm-season grass seed blended uniformly with sand.  By casting the sand/seed mixture evenly over the planting site, participants can visually assure that seed has been distributed according to the space calculations.
Riparian Buffer of wildflowers
The same seeded site less than four months later.
Monarch Pupa
A Monarch pupa from which the adult butterfly will emerge.

Photo of the Day

A migrating Monarch butterfly takes a break to feed on nectar from the blooms of a Frost Aster (Symphyotrichum pilosum), a common autumn wildflower also known as Heath Aster.

Fire and Ice at Conewago Falls

This morning, the Lower Susquehanna River Watershed experienced remotely the effects of fire and ice.

At daybreak, the cold air mass that brought the first freeze of the season to northernmost New England gave us a taste of the cold with temperatures below 50 degrees throughout.

The air temperature at daybreak in the Gettysburg Basin east of Conewago Falls.

At sunrise, the cloudless sky had a peculiar overcast look with no warm glow on buildings, vegetation, and terrain.  Soon, the sun was well above the horizon, yet there was still a sort of darkness across the landscape.

Smoke from massive wildland fires in the Pacific Coast States created a haze that persisted throughout the day in the Susquehanna valley.
Away from traffic and the odors of agriculture and urban life, the smell of wood smoke was easily detectable.  The haze from fires almost 3,000 miles away made it appear to be an overcast day at Conewago Falls.
Due to the sudden cold, there were no insects flying above the Susquehanna during the first hour of daylight this morning, so swallows gathered in the trees to conserve energy until the hunt would be more productive.
The diabase boulders at Conewago Falls retain heat and provide an even better refuge from the cold than a dead tree on a chilly morning.  Here, a juvenile and an adult Tree Swallow (center) are surrounded by Northern Rough-winged Swallows.  Hundreds of each of these migratory species were feeding at the falls today.
Two dozen or more Barn Swallows, including this juvenile, were seen among the swarming birds.
Several late Bank Swallows, including this one (bottom center), were among the flocks of migrants at Conewago Falls this morning.  One Cliff Swallow (Petrochelidon pyrrhonota) was seen as well.
A Great Egret (Ardea alba) and a Great Blue Heron.
An Osprey searching the clear pools and rapids for a morning meal.
A juvenile Bald Eagle with the same goal in mind.
The same Bald Eagle keeping a close watch on the Osprey.  Bald Eagles frequently ambush Ospreys to steal their catch.  For a young eagle, acquiring the skill of fish theft may improve its chances of survival, at least until the Ospreys head south.

All that bright filtered sunlight was ideal for photographing butterflies along the Conewago Falls shoreline.  Have a look.

During the late morning, dozens of Monarch butterflies migrated past Conewago Falls.  This one paused to feed.
The Viceroy (Limenitis archippus) is a Monarch mimic.  Its appearance fools would-be predators into thinking it is a Monarch and possesses the same foul flavor as the milkweed-raised model.
This Variegated Fritillary (Euptoieta claudia) was among the late-season butterflies at Conewago Falls.
The Common Buckeye is presently just that, very common on flowers and moist sandy soil around the falls.
The Painted Lady is a regularly-occurring migratory species of butterfly.
The Red Admiral is typically a common to abundant migrant.  So far in 2020, they are scarce in the lower Susquehanna valley. 

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.

Feathered Fallout

The NOAA National Weather Service radar images from last evening provided an indication that there may be a good fallout of birds at daybreak in the lower Susquehanna valley.  The moon was bright, nearly full, and there was a gentle breeze from the north to move the nocturnal migrants along.  The conditions were ideal.

Rising from daytime roosts in New York and Pennsylvania, then streaming south in moonlit skies, migrating birds are recorded as echoes on this post-sunset composite NEXRAD loop from last evening.  (NOAA/National Weather Service image)

The Riparian Woodlands at Conewago Falls were alive with migrants this morning.  American Robins and White-throated Sparrows were joined by new arrivals for the season: Brown Creeper (Certhia americana), Ruby-crowned Kinglets (Regulus calendula), Golden-crowned Kinglets (Regulus satrapa), Dark-eyed Junco (Junco hyemalis), and Yellow-rumped Warbler (Setophaga coronata).  These are the perching birds one would expect to have comprised the overnight flight.  While the individuals that will remain may not yet be among them, these are the species we will see wintering in the Mid-Atlantic states.  No trip to the tropics for these hardy passerines.

American Robins continued migratory flight into the first hour of daylight this morning.  Their calls are commonly heard at night as migrating individuals pass overhead.
White-throated Sparrows are nocturnal migrants, and are a familiar find on woodland edges and at suburban feeding stations through the winter.
Dark-eyed Juncos, also nocturnal migrants, are common winter residents in the Lower Susquehanna River Watershed, frequently visiting bird feeders.
Heavy rain earlier this week in the Susquehanna River drainage basin has flooded most of the Pothole Rocks; the rapids of Conewago Falls have returned.
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A Quick Getaway

It was a placid morning on Conewago Falls with blue skies dotted every now and then by a small flock of migrating robins or blackbirds.  The jumbled notes of a singing Winter Wren (Troglodytes hiemalis) in the Riparian Woodland softly mixed with the sounds of water spilling over the dam.  The season’s first Wood Ducks (Aix sponsa), Blue-winged Teal (Spatula discors), Herring Gull (Larus argentatus), Horned Larks (Eremophila alpestris), and White-throated Sparrows (Zonotrichia albicollis) were seen.

There was a small ruckus when one of the adult Bald Eagles from a local pair spotted an Osprey passing through carrying a fish.  This eagle’s effort to steal the Osprey’s catch was soon interrupted when an adult eagle from a second pair that has been lingering in the area joined the pursuit.  Two eagles are certainly better than one when it’s time to hustle a skinny little Osprey, don’t you think?

But you see, this just won’t do.  It’s a breach of eagle etiquette, don’t you know?  Soon both pairs of adult eagles were engaged in a noisy dogfight.  It was fussing and cackling and the four eagles going in every direction overhead.  Things calmed down after about five minutes, then a staring match commenced on the crest of the dam with the two pairs of eagles, the “home team” and the “visiting team”, perched about 100 feet from each other.  Soon the pair which seems to be visiting gave up and moved out of the falls for the remainder of the day.  The Osprey, in the meantime, was able to slip away.

In recent weeks, the “home team” pair of Bald Eagles, seen regularly defending territory at Conewago Falls, has been hanging sticks and branched tree limbs on the cross members of the power line tower where they often perch.  They seem only to collect and display these would-be nest materials when the “visiting team” pair is perched in the nearby tower just several hundred yards away…an attempt to intimidate by homesteading.  It appears that with winter and breeding time approaching, territorial behavior is on the increase.

The second migrating Osprey of the day ran the gauntlet of marauding eagles without incident.

In the afternoon, a fresh breeze from the south sent ripples across the waters among the Pothole Rocks.  The updraft on the south face of the diabase ridge on the east shore was like a highway for some migrating hawks, falcons, and vultures.  Black Vultures (Coragyps atratus) and Turkey Vultures streamed off to the south headlong into the wind after leaving the ridge and crossing the river.  A male and female Northern Harrier (Circus hudsonius), ten Red-tailed Hawks, two Red-shouldered Hawks (Buteo lineatus), six Sharp-shinned Hawks, and two Merlins crossed the river and continued along the diabase ridge on the west shore, accessing a strong updraft along its slope to propel their journey further to the southwest.  Four high-flying Bald Eagles migrated through, each following the east river shore downstream and making little use of the ridge except to gain a little altitude while passing by.

(Top and Middle) Turkey Vultures riding the fresh breeze and teetering to-and-fro on up-tilted wings.  This wing posture is known as a dihedral.  (Bottom) More than 100 migrating Black Vultures climbed high on the afternoon breeze to make an oblique crossing of the river and maintain a southbound course.

Late in the afternoon, the local Bald Eagles were again airborne and cackling up a storm.  This time they intercepted an eagle coming down the ridge toward the river and immediately forced the bird to climb if it intended to pass.  It turned out to be the best sighting of the day, and these “home team” eagles found it first.  It was a Golden Eagle (Aquila chrysaetos) in crisp juvenile plumage.  On its first southward voyage, it seemed to linger after climbing high enough for the Bald Eagles to loose concern, then finally selected the ridge route and crossed the river to head off to the southwest.

Ring-billed Gulls began feeding during the afternoon as clouds preceding stormy weather approached.
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State of Confusion

The humid rainy remains of Hurricane Nate have long since passed by Pennsylvania, yet mild wet weather lingers to confuse one’s sense of the seasons.  This gloomy misty day was less than spectacular for watching migrating birds and insects, but some did pass by.  Many resident animals of the falls are availing themselves of the opportunity to continue active behavior before the cold winds of autumn and winter force a change of lifestyle.

Warm drizzle at daybreak prompted several Northern Spring Peepers (Pseudacris crucifer crucifer) to begin calling from the wetlands in the Riparian Woodlands of Conewago Falls.  An enormous chorus of these calls normally begins with the first warm rains of early spring to usher in this tiny frog’s mating season.  Today, it was just a few “peeps” among anxious friends.

The tiny Northern Spring Peeper is recognized by the dark “X” across its back.  Soon, shelter must be found among loose bark and fallen logs to commence hibernation.  Emergence, often prompted by warm spring rains, will quickly be followed by a growing chorus of breeding calls as sometimes hundreds of these frogs assemble in vernal pools where mating will then occur.

Any additional river flow that resulted from the rains of the previous week is scarcely noticeable among the Pothole Rocks.  The water level remains low, the water column is fairly clear, and the water temperatures are in the 60s Fahrenheit.

It’s no real surprise then to see aquatic turtles climbing onto the boulders in the falls to enjoy a little warmth, if not from the sun, then from the stored heat in the rocks.  As usual, they’re quick to slide into the depths soon after sensing someone approaching or moving nearby.  Seldom found anywhere but on the river, these skilled divers are Common Map Turtles (Graptemys geographica), also known as Northern Map Turtles.  Their paddle-like feet are well adapted to swimming in strong current.  They are benthic feeders, feasting upon a wide variety of invertebrates found among the stone and substrate of the river bottom.

Adult Common Map Turtles hibernate communally on the river bottom in a location protected from ice scour and turbulent flow, often using boulders, logs, or other structures as shelter from strong current.  The oxygenation of waters tumbling through Conewago Falls may be critical to the survival of the turtles overwintering downstream.  Dissolved oxygen in the water is absorbed by the nearly inactive turtles as they remain submerged at their hideout through the winter.  Though Common Map Turtles, particularly males, may occasionally move about in their hibernation location, they are not seen coming to the surface to breathe.

The Common Map Turtles in the Susquehanna River basin are a population disconnected from that found in the main range of the species in the Great Lakes and upper Mississippi basin.  Another isolated population exists in the Delaware River.

Common Map Turtles, including this recently hatched young seen in August, are often observed climbing onto rocks in the river.
Note the oversize swimming fin adaptations of the feet on this adult Common Map Turtle found among the Pothole Rocks in Conewago Falls.  Young and adults are capable of navigating some strong current to feed and escape danger.
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SOURCES

Committee on the Status of Endangered Wildlife in Canada.  2002.  Status Report of the Northern Map Turtle.  Canadian Wildlife Service.  Ottawa, Ontario.

Summer Breeze

A moderate breeze from the south placed a headwind into the face of migrants trying to wing their way to winter quarters.  The urge to reach their destination overwhelmed any inclination a bird or insect may have had to stay put and try again another day.

Blue Jays were joined by increasing numbers of American Robins crossing the river in small groups to continue their migratory voyages.  Killdeer (Charadrius vociferous) and a handful of sandpipers headed down the river route.  Other migrants today included a Cooper’s Hawk (Accipiter cooperii), Eastern Bluebirds (Sialia sialis), and a few Common Mergansers (Mergus merganser), House Finches (Haemorhous mexicanus), and Common Grackles (Quiscalus quiscula).

The afternoon belonged to the insects.  The warm wind blew scores of Monarchs toward the north as they persistently flapped on a southwest heading.  Many may have actually lost ground today.  Painted Lady (Vanessa cardui) and Cloudless Sulphur butterflies were observed battling their way south as well.  All three of the common migrating dragonflies were seen: Common Green Darner (Anax junius), Wandering Glider (Pantala flavescens), and Black Saddlebags (Tramea lacerata).

The warm weather and summer breeze are expected to continue as the rain and wind from Hurricane Nate, today striking coastal Alabama and Mississippi, progresses toward the Susquehanna River watershed during the coming forty-eight hours.

This Great Blue Heron was joined by numerous other fishermen and a good number of sightseers in the falls today.
A colorful young Northern Water Snake (Nerodia sipedon) takes advantage of the sun-heated surface of a Pothole Rock to remain nimble and active.  Cooler weather will soon compel this and other reptiles to find shelter for winter hibernation.
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Blue Jay Way

The Neotropical birds that raised their young in Canada and in the northern United States have now logged many miles on their journey to warmer climates for the coming winter.  As their density decreases among the masses of migrating birds, a shift to species with a tolerance for the cooler winter weather of the temperate regions will be evident.

Though it is unusually warm for this late in September, the movement of diurnal migrants continues.  This morning at Conewago Falls, five Broad-winged Hawks (Buteo platypterus) lifted from the forested hills to the east, then crossed the river to continue a excursion to the southwest which will eventually lead them and thousands of others that passed through Pennsylvania this week to wintering habitat in South America.  Broad-winged Hawks often gather in large migrating groups which swarm in the rising air of thermal updrafts, then, after gaining substantial altitude, glide away to continue their trip.  These ever-growing assemblages from all over eastern North America funnel into coastal Texas where they make a turn to south around the Gulf of Mexico, then continue on toward the tropics.  In the coming weeks, a migration count at Corpus Christi in Texas could tally 100,000 or more Broad-winged Hawks in a single day as a large portion of the continental population passes by.  You can track their movement and that of other diurnal raptors as recorded at sites located all over North America by visiting hawkcount.org on the internet.  Check it out.  You’ll be glad you did.

Nearly all of the other migrants seen today have a much shorter flight ahead of them.  Red-bellied Woodpeckers (Melanerpes carolinus), Red-headed Woodpeckers (Melanerpes erythrocephalus), and Northern Flickers (Colaptes auratus) were on the move.  Migrating American Robins (Turdus migratorius) crossed the river early in the day, possibly leftovers from an overnight flight of this primarily nocturnal migrant.  The season’s first Great Black-backed Gulls (Larus marinus) arrived.  American Goldfinches are easily detected by their calls as they pass overhead.  Look carefully at the goldfinches visiting your feeder, the birds of summer are probably gone and are being replaced by migrants currently passing through.

By far, the most conspicuous migrant today was the Blue Jay.  Hundreds were seen as they filtered out of the hardwood forests of the diabase ridge to cautiously cross the river and continue to the southwest.  Groups of five to fifty birds would noisily congregate in trees along the river’s edge, then begin flying across the falls.  Many wary jays abandoned their small crossing parties and turned back.  Soon, they would try the trip again in a larger flock.

Sensing that they are being watched, Blue Jays are hesitant to fly across the narrow Susquehanna at Conewago Falls without first assembling into a flock.  The local constabulary often penalizes those who freelance and do not move in orderly groups.

A look at this morning’s count reveals few Neotropical migrants.  With the exception of the Broad-winged Hawks and warblers, the migratory species seen today will winter in a sub-tropical temperate climate, primarily in the southern United States, but often as far north as the lower Susquehanna River valley.  The individual birds observed today will mostly continue to a winter home a bit further south.  Those that will winter in the area of Conewago Falls will arrive in October and later.

The Great Blue Heron (Ardea herodius) can be found year-round at Conewago Falls, provided there is open water and adequate food.  Migrants from breeding colonies to the north will soon supplement the local population.
The Double-crested Cormorant (Phalacrocorax auritus) is a summer resident at Conewago Falls.  Migration of the local population and of those from further north will soon begin.  All will be gone by the time ice forms on the river.  Cormorants are often seen drying their feathers in sunlight following a series of feeding dives.

The long-distance migrating insect so beloved among butterfly enthusiasts shows signs of improving numbers.  Today, more than two dozen Monarchs were seen crossing the falls and slowly flapping and gliding their way to Mexico.

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Yellowlegs for Breakfast

A few nocturnal migrants flew through the moonlit night to arrive at Conewago Falls for a sunrise showing this morning.  A dozen warblers were in the treetops and a Wood Thrush (Hylocichla mustelina) chattered away in the understory of the Riparian Woodlands.  Three species of shorebirds were in the falls and on the Pothole Rocks: Least Sandpiper (Calidris minutilla), Lesser Yellowlegs (Tringa flavipes), and Greater Yellowlegs (Tringa melanoleuca).

A Greater Yellowlegs (right) and two Lesser Yellowlegs sandpipers dropped by for breakfast.

The diurnal migration was highlighted by a Merlin (Falco columbarius), an Osprey, and a Bald Eagle, each flying down the river.  Most of the other birds in the falls seemed content to linger and feed.  There’s no need to hurry folks, only trouble lurks down there in paradise at the moment.

A light to moderate flight of nocturnal migrants in the eastern United States is displayed on NOAA National Weather Service NEXRAD radar at 4:58 AM EDT.  The eye of Hurricane Irma can be seen approaching the Florida Keys.  (NOAA/National Weather Service image)
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Piles of Green Tape

A couple of inches of rain this week caused a small increase in the flow of the river, just a burp, nothing major.  This higher water coincided with some breezy days that kicked up some chop on the open waters of the Susquehanna upstream of Conewago Falls.  Apparently it was just enough turbulence to uproot some aquatic plants and send them floating into the falls.

Piled against and upon the upstream side of many of the Pothole Rocks were thousands of two to three feet-long flat ribbon-like opaque green leaves of Tapegrass, also called Wild Celery, but better known as American Eelgrass (Vallisneria americana).  Some leaves were still attached to a short set of clustered roots.  It appears that most of the plants broke free from creeping rootstock along the edge of one of this species’ spreading masses which happened to thrive during the second half of the summer.  You’ll recall that persistent high water through much of the growing season kept aquatic plants beneath a blanket of muddy current.  The American Eelgrass colonies from which these specimens originated must have grown vigorously during the favorable conditions in the month of August.  A few plants bore the long thread-like pistillate flower stems with a fruit cluster still intact.  During the recent few weeks, there have been mats of American Eelgrass visible, the tops of their leaves floating on the shallow river surface, near the east and west shorelines of the Susquehanna where it begins its pass through the Gettysburg Basin near the Pennsylvania Turnpike bridge at Highspire.  This location is a probable source of the plants found in the falls today.

Uprooted American Eelgrass floating into the Pothole Rocks under the power of a north wind.  Note the white thread-like pistillate flower stem to the left and the small rooted specimen to the upper right.  The latter is likely a plant from the creeping rootstock on the edge of a colony.  As a native aquatic species, American Eelgrass is a critical link in the Susquehanna River and Chesapeake Bay food chain.  Its decimation by pollution during the twentieth century led to migration pattern alterations and severe population losses for the Canvasback (Aythya valisineria) duck.
American Eelgrass, a very small specimen, found growing in a low-lying Pothole Rock alongside the accumulations of freshly arriving material from upstream.  Note that the creeping rootstock has leaves growing from at least three nodes on this plant.  Eelgrass dislocations are regular occurrences which sometimes begin new colonies, like the small one seen here in this Diabase Pothole Rock Microhabitat.

The cool breeze from the north was a perfect fit for today’s migration count.  Nocturnal migrants settling down for the day in the Riparian Woodlands at sunrise included more than a dozen warblers and some Gray Catbirds (Dumetella carolinensis).  Diurnal migration was underway shortly thereafter.

A moderate flight of nocturnal migrants is indicated around NEXRAD sites in the northeastern states at 3:18 AM EDT.  The outer rain bands of Hurricane Irma can be seen approaching the Florida Keys as the storm closes in on the peninsula.  (NOAA/National Weather Service image)

Four Bald Eagles were counted as migrants this morning.  Based on plumage, two were first-year eagles (Juvenile) seen up high and flying the river downstream, one was a second-year bird (Basic I) with a jagged-looking wing molt, and a third was probably a fourth year (Basic III) eagle looking much like an adult with the exception of a black terminal band on the tail.  These birds were the only ones which could safely be differentiated from the seven or more Bald Eagles of varying ages found within the past few weeks to be lingering at Conewago Falls.  There were as many as a dozen eagles which appeared to be moving through the falls area that may have been migrating, but the four counted were the only ones readily separable from the locals.

Red-tailed Hawks (Buteo jamaicensis) were observed riding the wind to journey not on a course following the river, but flying across it and riding the updraft on the York Haven Diabase ridge from northeast to southwest.

Bank Swallows (Riparia riparia) seem to have moved on.  None were discovered among the swarms of other species today.

Ruby-throated Hummingbirds, Caspian Terns, Cedar Waxwings (Bombycilla cedrorum), and Chimney Swifts (Chaetura pelagica) were migrating today, as were Monarch butterflies.

Not migrating, but always fun to have around, all four wise guys were here today.  I’m referring to the four members of the Corvid family regularly found in the Mid-Atlantic states: Blue Jay (Cyanocitta cristata), American Crow (Corvus brachyrhynchos), Fish Crow (Corvus ossifragus), and Common Raven (Corvus corax).

It looks like a big Blue Jay, but it’s not.  This Belted Kingfisher (Megaceryle alcyon) takes a break after flying around the falls trying to shake a marauding Ruby-throated Hummingbird off its tail.
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SOURCES

Klots, Elsie B.  1966.  The New Field Book of Freshwater Life.  G. P. Putnam’s Sons.  New York, NY.

Suggestive Selling

A Baltimore Oriole (Icterus galbula) glowed in the first sunlight of the day as it began illuminating the treetops.  I’m not certain of the cause, but I often have the urge to dig into a bowl of orange sherbet after seeing one these magnificent blackbirds.  That’s right, in the Americas, orioles and blackbirds are members of the same family, Icteridae.  Look at blackbirds more carefully, you might see the resemblance.

Sunshine at dawn and migrating warblers were again active in the foliage.  Eight species were identified today.  Off to the tropics they go.  To the land of palm and citrus, yes citrus…limes, lemons, grapefruits, and oranges.

The Ruby-throated Hummingbirds (Archilochus colubris) are on the way toward the gulf states, then on to Central and South America.  Five dashed by the rocky lookout in the falls this morning.  Remember, keep your feeders clean, wash and rinse all the parts, and refill them with a fresh batch of “nectar”, four or five parts water to one part sugar.  Repeating this process daily during hot weather should keep contamination from overtaking your feeder.  It’s not a bad idea to rotate two feeders.  Have one cleaned, rinsed, and air drying while the second is filled and in use at your feeding station, then just swap them around.  Your equipment will be just as clean as it is at the sanitary dairy…you know, where they make sherbet.

The first of the season Caspian Terns (Hydroprogne caspia), giant freshwater versions of the terns you see at the seashore, passed through the falls late this morning.  Their bills are blood-red, not orange like the more familiar terns on the coast.  They’re stunning.

Ring-billed Gulls (Larus delawarensis) have been at the falls for several weeks.  Total numbers and the composition of the age groups in the flock change over the days, so birds appear to be trickling through and are then replaced by others coming south.  The big push of southbound migrants for this and many other species that winter locally in the Mid-Atlantic region and in the southern United States is still more than a month away.  There are still plenty more birds to come after the hours of daylight are reduced and the temperatures take a dip.

A Ring-billed Gull on the lookout for a morning snack.  They’ll eat almost anything and do a good job of keeping the river picked clean of the remains of animals that have met misfortune.  They’ll linger around landfills, hydroelectric dams, and fast-food restaurant parking lots through the winter.
Turkey Vultures (Cathartes aura) are common around the falls due to the abundance of carrion in the vicinity and because of the strong thermal updrafts of air over the sun-heated Pothole Rocks.  These rising currents provide lift for circling vultures.  We would expect migrating birds of a number of species will also take advantage of these thermals to gain altitude and extend the distance of their glides.

Some migrating butterflies were counted today.  Cloudless Sulphurs, more of a vagrant than a migrant, and, of course, Monarchs.  I’ll bet you know the Monarch, it’s black and orange.  How can you miss them, colored orange.

That’s it, that’s all for now, I bid you adieu…I’m going to have a dip of orange sherbet, or two.

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Fussy Eaters

She ate only toaster pastries…that’s it…nothing else.  Every now and then, on special occasions, when a big dinner was served, she’d have a small helping of mashed potatoes, no gravy, just plain, thank you.  She received all her nutrition from several meals a week of macaroni and cheese assembled from processed ingredients found in a cardboard box.  It contains eight essential vitamins and minerals, don’t you know?  You remember her, don’t you?

Adult female butterflies must lay their eggs where the hatched larvae will promptly find the precise food needed to fuel their growth.  These caterpillars are fussy eaters, with some able to feed upon only one particular species or genus of plant to grow through the five stages, the instars, of larval life.  The energy for their fifth molt into a pupa, known as a chrysalis, and metamorphosis into an adult butterfly requires mass consumption of the required plant matter.  Their life cycle causes most butterflies to be very habitat specific.  These splendid insects may visit the urban or suburban garden as adults to feed on nectar plants, however, successful reproduction relies upon environs which include suitable, thriving, pesticide-free host plants for the caterpillars.  Their survival depends upon more than the vegetation surrounding the typical lawn will provide.

The Monarch (Danaus plexippus), a butterfly familiar in North America for its conspicuous autumn migrations to forests in Mexico, uses the milkweeds (Asclepias) almost exclusively as a host plant.  Here at  Conewago Falls, wetlands with Swamp Milkweed (Asclepias incarnata) and unsprayed clearings with Common Milkweed (A. syriaca) are essential to the successful reproduction of the species.  Human disturbance, including liberal use of herbicides, and invasive plant species can diminish the biomass of the Monarch’s favored nourishment, thus reducing significantly the abundance of the migratory late-season generation.

Monarch caterpillar after a fourth molt.  The fifth instar feeding on Swamp Milkweed.
A fifth molt begets the Monarch pupa, the chrysalis, from which the showy adult butterfly will emerge.
Adult Monarch feeding on Goldenrod (Solidago) nectar.

Butterflies are good indicators of the ecological health of a given environment.  A diversity of butterfly species in a given area requires a wide array of mostly indigenous plants to provide food for reproduction.  Let’s have a look at some of the species seen around Conewago Falls this week…

An adult Silvery Checkerspot (Chlosyne nycteis) visiting a nectar plant, Partridge Pea (Chamaecrista fasciculata).  Wingstem (Verbesina alternifolia), a plant of the Riparian Woodlands, is among the probable hosts for the caterpillars.
A Gray Hairstreak (Strymon melinus) visits Crown Vetch, a possible host plant.  Other potential larval food in the area includes Partridge Pea, Halberd-leaved Rose Mallow (Hibiscus laevis) of the river shoreline, and Swamp Rose Mallow (Hibiscus moscheutos), a plant of wetlands.
The Eastern Tailed Blue (Cupido comyntas) may use Partridge Pea , a native wildflower species, and the introduced Crown Vetch (Securigera/Coronilla varia) as host and nectar plants at Conewago Falls.
The Least Skipper (Ancyloxypha numitor) is at home among tall grasses in woodland openings, at riverside, and in the scoured grassland habitat of the Pothole Rocks in the falls.  Host plants available include Switchgrass (Panicum vigatum), Freshwater Cordgrass (Spartina pectinata), and Foxtails (Setaria).
The Zabulon Skipper (Poanes zabulon) is an inhabitant of moist clearings where the caterpillars may feed upon Lovegrasses (Eragrostis) and Purpletop (Tridens flavus).
The Eastern Tiger Swallowtail (Papilio glaucus), a female seen here gathering nectar from Joe-Pye Weed (Eutrochium), relies upon several forest trees as hosts. Black Cherry (Prunus serotina), Willow (Salix), Yellow Poplar (Liriodendron tulipifera), also known as Tuliptree, and Green Ash (Fraxinus pennsylvanica) are among the local species known to be used.  The future of the latter food species at Conewago Falls is doubtful.  Fortunately for the Eastern Tiger Swallowtail, the “generalist” feeding requirements of this butterfly’s larvae enable the species to survive the loss of a host plant.
A female Eastern Tiger Swallowtail, black morph, gathering nectar from Joe-Pye Weed.
The Zebra Swallowtail (Protographium marcellus), seen here on Joe-Pye Weed, feeds exclusively upon Pawpaw (Asimina) trees as a caterpillar.  This butterfly species may wander, but its breeding range is limited to the moist Riparian Woodlands where colonial groves of Pawpaw may be found.  The Common Pawpaw (Asimina triloba), our native species in Pennsylvania, and the Zebra Swallowtail occur at the northern edge of their geographic ranges in the Lower Susquehanna River Watershed.  Planting Pawpaw trees as an element of streamside reforestation projects certainly benefits this marvelous butterfly.

The spectacularly colorful butterflies are a real treat on a hot summer day.  Their affinity for showy plants doubles the pleasure.

By the way, I’m certain by now you’ve recalled that fussy eater…and how beautiful she grew up to be.

SOURCES

Brock, Jim P., and Kaufman, Kenn.  2003.  Butterflies of North America.  Houghton Mifflin Company.  New York, NY.