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 (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.
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 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 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 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.
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.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.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.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.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.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……and stocked Ring-necked Pheasants that do nest and raise young there.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.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.Savanna-like grasslands with oaks and other scattered large trees, some of them dead, make attractive nesting habitat for the uncommon Red-headed Woodpecker.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.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. The Bear Oak regenerates readily from top kill caused by fire.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 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.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.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.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 and the equipment and techniques they use to conduct a burn.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.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.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.Crews proceed uphill from the location of the test fire while igniting combustibles along both flanks of the area being treated.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.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.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.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.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).Crews proceed up the slope while maintaining the perimeter by igniting dry plant material along the flanks of the burn zone.Ignition complete, the crews monitor the fire.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.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.And later in the summer, Eastern Tiger Swallowtails on Joe-pye Weed.Indiangrass in flower in mid-summer.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.
The Northern Flicker is one of four migratory woodpeckers currently working their way south through the Lower Susquehanna River Watershed. Flickers, Red-headed Woodpeckers, Red-bellied Woodpeckers, and Yellow-bellied Sapsuckers, not only transit the area each spring and fall, but remain in lesser numbers for the winter. And while a population of each of the first three are regular breeders in our region, thus allowing observers to see these species year-round, the sapsucker nests only to our north.
A juvenile Red-headed Woodpecker surveys the morning landscape. In the lower Susquehanna watershed, Red-headed Woodpeckers are an uncommon summer breeder requiring large dead oak trees in semi-open habitat for nesting. They can occasionally be found during winter in mature oak woods, appearing most frequently west of the river at places including Gifford Pinchot State Park. Fall migrants are seen along local ridges in September and October.
Let’s take a quiet stroll through the forest to have a look around. The spring awakening is underway and it’s a marvelous thing to behold. You may think it a bit odd, but during this walk we’re not going to spend all of our time gazing up into the trees. Instead, we’re going to investigate the happenings at ground level—life on the forest floor.
Rotting logs and leaf litter create the moisture retaining detritus in which mesic forest plants grow and thrive. Note the presence of mosses and a vernal pool in this damp section of forest.The earliest green leaves in the forest are often those of the Skunk Cabbage (Simplocarpus foetidus). This member of the arum family gets a head start by growing in the warm waters of a spring seep or in a stream-fed wetland. Like many native wildflowers of the forest, Skunk Cabbage takes advantage of early-springtime sun to flower and grow prior to the time in late April when deciduous trees grow foliage and cast shade beneath their canopy.Among the bark of dead and downed trees, the Mourning Cloak butterfly (Nymphalis antiopa) hibernates for the winter. It emerges to alight on sun-drenched surfaces in late winter and early spring.Another hibernating forest butterfly that emerges on sunny early-spring days is the Eastern Comma (Polygonia comma), also known as the Hop Merchant.In a small forest brook, a water strider (Gerridae) chases its shadow using the surface tension of the water to provide buoyancy. Forests are essential for the protection of headwaters areas where our streams get their start.Often flooded only in the springtime, fish-free pools of water known as vernal ponds are essential breeding habitat for many forest-dwelling amphibians. Unfortunately, these ephemeral wetland sites often fall prey to collecting, dumping, filling, and vandalism by motorized and non-motorized off-roaders, sometimes resulting in the elimination of the populations of frogs, toads, and salamanders that use them.Wood Frogs (Lithobates sylvaticus) emerge from hiding places among downed timber and leaf litter to journey to a nearby vernal pond where they begin calling still more Wood Frogs to the breeding site.Wood Frog eggs must hatch and tadpoles must transform into terrestrial frogs before the pond dries up in the summertime. It’s a risky means of reproduction, but it effectively evades the enormous appetites of fish.When the egg laying is complete, adult Wood Frogs return to the forest and are seldom seen during the rest of the year.In early spring, Painted Turtles emerge from hideouts in larger forest pools, particularly those in wooded swamps, to bask in sunny locations.Dead standing trees, often called snags, are essential habitats for many species of forest wildlife. There is an entire biological process, a micro-ecosystem, involved in the decay of a dead tree. It includes fungi, bacteria, and various invertebrate animals that reduce wood into the detritus that nourishes and hydrates new forest growth.Birds like this Red-headed Woodpecker feed on insects found in large snags and nest almost exclusively in them. Many species of wildlife rely on dead trees, both standing and fallen, during all or part of their lives.
There certainly is more to a forest than the living trees. If you’re hiking through a grove of timber getting snared in a maze of prickly Multiflora Rose (Rosa multiflora) and seeing little else but maybe a wild ungulate or two, then you’re in a has-been forest. Logging, firewood collection, fragmentation, and other man-made disturbances inside and near forests take a collective toll on their composition, eventually turning them to mere woodlots. Go enjoy the forests of the lower Susquehanna valley while you still can. And remember to do it gently; we’re losing quality as well as quantity right now—so tread softly.
The White-tailed Deity in a woodlot infested by invasive tangles of Multiflora Rose.
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.
Temperatures plummeted to well below freezing during the past two nights, but there was little sign of it in Conewago Falls this morning. The fast current in the rapids and swirling waters in flooded Pothole Rocks did not freeze. Ice coated the standing water in potholes only in those rocks lacking a favorable orientation to the sun for collecting solar heat during the day to conduct into the water during the cold nights.
On the shoreline, the cold snap has left its mark. Ice covers the still waters of the wetlands. Frost on exposed vegetation lasted until nearly noontime in shady areas. Insect activity is now grounded and out of sight. The leaves of the trees tumble and fall to cover the evidence of a lively summer.
The nocturnal bird flight is narrowing down to just a few species. White-throated Sparrows, a Swamp Sparrow (Melospiza georgiana), and Song Sparrows are still on the move. Though their numbers are not included in the migration count, hundreds of the latter are along the shoreline and in edge habitat around the falls right now. Song Sparrows are present year-round, migrate at night, and are not seen far from cover in daylight, so migratory movements are difficult to detect. It is certain that many, if not all of the Song Sparrows here today have migrated and arrived here recently. The breeding population from spring and summer has probably moved further south. And many of the birds here now may remain for the winter. Defining the moment of this dynamic, yet discrete, population change and logging it in a count would certainly require different methods.
Song Sparrows are now abundant in the brushy edges of fields and woodlands. They may even break into song on sunny days.
Diurnal migration was foiled today by winds from southerly directions and moderating temperatures. The only highlight was an American Robin flight that extended into the morning for a couple of hours after daybreak and totaled over 800 birds. This flight was peppered with an occasional flock of blackbirds. Then too, there were the villains.
CLICK ON THE LOGO FOR TODAY’S MIGRATION COUNT TOTALS
They’re dastardly, devious, selfish, opportunistic, and abundant. Today, they were the most numerous diurnal migrant. Their numbers made this one of the biggest migration days of the season, but they are not recorded on the count sheet. It’s no landmark day. They excite no one. For the most part, they are not recognized as migrants because of their nearly complete occupation of North America south of the taiga. If people build on it or alter it, these birds will be there. They’re everywhere people are. If the rotten attributes of man were wrapped up into one bird, an “anthropoavian”, this would be it.
Meet the European Starling (Sturnus vulgaris). Introduced into North America in 1890, the species has spread across the entire continent. It nests in cavities in buildings and in trees. Starlings are aggressive, particularly when nesting, and have had detrimental impacts on the populations of native cavity nesting birds, particularly Red-headed Woodpeckers, Purple Martins (Progne subis), and Eastern Bluebirds. They commonly terrorize these and other native species to evict them from their nest sites. European Starlings are one of the earlier of the scores of introduced plants and animals we have come to call invasive species.
Noisy flocks of European Starlings are right at home on man-made structures in city and country.
Today, thousands of European Starlings were on the move, working their way down the river shoreline and raiding berries from the vines and trees of the Riparian Woodlands. My estimate is between three and five thousand migrated through during the morning. But don’t worry, thousands more will be around for the winter.
European Starlings mob a Sharp-shinned Hawk from above, a common behavior.An Eastern Bluebird feeds on the few berries left untouched by passing European Starlings.
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.CLICK ON THE LOGO FOR TODAY’S MIGRATION COUNT TOTALS
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.
CLICK ON THE LOGO FOR TODAY’S MIGRATION COUNT TOTALS
