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.

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.

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.

Big Winds Bring Big Birds

Colder temperatures and gusty northwest winds are prompting our largest migratory raptors to continue their southward movements.  Here are some of the birds seen earlier today riding updrafts of air currents along one of the Lower Susquehanna River Watershed’s numerous ridges.

Turkey Vulture
Hundreds of Turkey Vultures are presently passing through the lower Susquehanna valley on their way south.  Their winter abundance here is largely determined by the availability of carrion.
Hatch-year Bald Eagle
The late-season push of Bald Eagles is now underway.  Today, ten or more birds were seen at several of the region’s hawk watches.  This particular eagle is a juvenile, a hatch-year bird, with an unusually large area of white in the tail.
Red-tailed Hawks
Red-tailed hawks pass a hawk-counting station while gliding away to the southwest within an energy-saving updraft of ridge-deflected wind.
Golden Eagle and Red-shouldered Hawk
A migrating Golden Eagle keeps a wary eye on a marauding Red-shouldered Hawk.  This Golden Eagle is young, either in its hatch year or second year of life.
Red-tailed Hawk
A Red-tailed Hawk migrating during a late-afternoon snow shower.

As winter begins clawing at the door, now is great time to visit a hawk watch near you to see these late-season specialties.  Remember to dress in layers and to click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page.  Hawkwatcher’s Helper is your guide to regional hawk watching locations and raptor identification.  Be sure to check it out.  And remember, it’s cold on top of those ridges, so don’t forget your hat, your gloves, and your chap stick!

Are Your Eggs All They’re Cracked Up To Be?

Looks like I’m gonna be in the doghouse again—this time by way of the hen house.  But why should I care?  Here we go.

A few weeks ago, back when eggs were still selling for less than five dollars a dozen, the Pennsylvania Department of Agriculture renewed calls for owners and caretakers of outdoor flocks of domestic poultry (backyard chickens) to keep their birds indoors to protect them from the spread of  bird flu—specifically “Highly Pathogenic Avian Influenza” (H.P.A.I.).  At least one story edited and broadcast by a Susquehanna valley news outlet gave the impression that “vultures and hawks” are responsible for the spread of avian flu in chickens.  To see if recent history supports such a deduction, let’s have a look at the U.S.D.A.’s Animal and Plant Health Inspection Service’s 2022-2023 list of the  detection of Highly Pathogenic Avian Influenza in birds affected in counties of the Lower Susquehanna River Watershed in Pennsylvania.

H.P.A.I. 2022 Confirmed Detections as of January 13, 2023

This listing includes date of detection, county of collection, type/species of bird, and number of birds affected.  WOAH (World Organization for Animal Health) birds include backyard poultry, game birds raised for eventual release, domestic pet species, etc.

12/30/2022  Adams            Black Vulture

12/15/2022   Lancaster     Canada Goose

12/15/2022   Lebanon        Black Vulture

12/15/2022   Adams            Black Vulture (3)

11/8/2022     Cumberland Black Vulture (4)

11/4/2022      Dauphin         WOAH Non-Poultry (130)

10/19/2022   Dauphin         Captive Wild Rhea (4)

10/17/2022   Adams            Commercial Turkey (15,100)

10/11/2022    Adams            WOAH Poultry (2,800)

9/30/2022    Lancaster      Mallard

9/30/2022    Lancaster      Mallard

9/29/2022     Lancaster     WOAH Non-Poultry (180)

9/29/2022     York                 Commercial Turkey (25,900)

8/24/2022     Dauphin         Captive Wild Crane

7/15/2022      Lancaster     Great Horned Owl

7/15/2022      York                 Bald Eagle

7/15/2022      Dauphin         Bald Eagle

6/16/2022      Dauphin         Black Vulture

6/16/2022      Dauphin         Black Vulture (4)

5/31/2022      Lancaster      Black Vulture (2)

5/31/2022      Lancaster      Black Vulture

5/10/2022-Lncstr-Commercial Egg Layer (72,300)

4/29/2022-Lncstr-Commercial Duck (19,300)

4/27/2022-Lncstr-Commercial Broiler (18,100)

4/26/2022-Lncstr-Commercial Egg Layer (307,400)

4/22/2022-Lncstr-Commercial Broiler (50,300)

4/20/2022-Lncstr-Commercial Egg Layer (1,127,700)

4/20/2022-Lncstr-Commercial Egg Layer (879,400)

4/15/2022-Lncstr-Commercial Egg Layer (1,380,500)

In the Lower Susquehanna River Watershed, it’s pretty obvious that the outbreak of avian flu got its foothold inside some of the area’s big commercial poultry houses.  Common sense tells us that hawks, vultures, and other birds didn’t migrate north into the Lower Susquehanna River Watershed carrying bird flu, then kick in the doors of the enclosed hen houses to infect the flocks of chickens therein.   Anyone paying attention during these past three years knows that isolation and quarantine are practices more easily proposed than sustained.  Human footprints are all over the introduction of this infection into these enormous flocks.  Simply put, men don’t wipe their feet when no one is watching!  The outbreak of bird flu in these large operations was brought under control quickly, but not until teams of state and federal experts arrived to assure proper sanitary and isolation practices were being implemented and used religiously to prevent contaminated equipment, clothing, vehicles, feed deliveries, and feet from transporting virus to unaffected facilities.  Large poultry houses aren’t ideal enclosures with absolute capabilities for excluding or containing viruses and other pathogens.  Exhaust systems often blow feathers and waste particulates into the air surrounding these sites and present the opportunity for flu to be transported by wind or service vehicles and other conveyances that pass through contaminated ground then move on to other sites—both commercial and non-commercial.  Waste material and birds (both dead and alive) removed from commercial poultry buildings can spread contamination during transport and after deposition.  The sheer volume of the potentially infected organic material involved in these large poultry operations makes absolute containment of an outbreak nearly impossible.

A farm with a biosecurity perimeter or control area.  (United States Department of Agriculture Animal and Plant Inspection Service image)
A U.S.D.A. Animal and Plant Inspection Service Veterinary Services employee decontaminates footwear at the entrance to a biosecurity zone.  (United States Department of Agriculture Animal and Plant Inspection Service image)

Looking at the timeline created by the list of U.S.D.A. detections, the opportunity for bird flu to leave the commercial poultry loop probably happened when wild birds gained access to stored or disposed waste and dead animals from an infected commercial poultry operation.  For decades now, many poultry operations have dumped dead birds outside their buildings where they are consumed by carrion-eating mammals, crows, vultures, Bald Eagles, and Red-tailed Hawks.  For these species, discarded livestock is one of the few remaining food sources in portions of the Lower Susquehanna River Watershed where high-intensity farming has eliminated other forms of sustenance.  They will travel many miles and gather in unnatural concentrations to feast on these handouts—creating ideal circumstances for the spread of disease.

The sequence of events indicated by the U.S.D.A. list would lead us to infer that vultures and Bald Eagles were quick to find and consume dead birds infected with H5N1—either wild species such as waterfowl or more likely domestic poultry from commercial operations or from infectious backyard flocks that went undetected.  As the report shows, Black Vultures in particular seem to be susceptible to morbidity.  Their frequent occurrence as victims highlights the need to dispose of potentially infectious poultry carcasses properly—allowing no access for hungry wildlife including scavengers.

Black Vultures
Black Vultures and other scavengers including Bald Eagles are attracted to improperly discarded poultry carcasses and will often loiter in areas where dumping occurs.

The positive test on a Great Horned Owl is an interesting case.  While the owl may have consumed an infected wild bird such as a crow, there is the possibility that it consumed or contacted a mammalian scavenger that was carrying the virus.  Aside from rodents and other small mammals, Great Horned Owls also prey upon Striped Skunks with some regularity.  Most of the dead poultry from flu-infected commercial flocks was buried onsite in rows of above-ground mounds.  Skunks sniff the ground for subterranean fare, digging up invertebrates and other food.  Buried chickens at a flu disposal site would constitute a feast for these opportunistic foragers.  A skunk would have no trouble at all finding at least a few edible scraps at such a site.  Then a Great Horned Owl could easily seize and feed upon such a flu virus-contaminated skunk.

Striped Skunk
Striped Skunks and many other mammals are readily attracted by improperly discarded poultry carcasses.

BACKYARD POULTRY

Before we proceed, the reader must understand the seldom-stated and never advertised mission of the Pennsylvania Department of Agriculture—to protect the state’s agriculture industry.  That’s it; that’s the bottom line.  Regulation and enforcement of matters under the purview of the agency have their roots in this goal.  While they may also protect the public health, animal health, and other niceties, the underlying purpose of their existence in its current manifestation is to protect the agriculture industry(s) as a whole.

This is not a trait unique to the Pennsylvania Department of Agriculture.  It is at the core of many other federal and state agencies as well.  Following the publication of Upton Sinclair’s The Jungle in 1906, a novel decrying “wage slavery” in the meat packing industry, the federal government took action, not for the purpose of improving the working conditions for labor, but to address the unsanitary food-handling practices described in the book by creating an inspection program to restore consumer confidence in the commercially-processed meat supply so that the industry would not crumble.

Locally, few things make the dairy industry and the Pennsylvania Department of Agriculture more nervous than small producers selling “raw milk”.  In the days before pasteurization and refrigeration, people were frequently sickened and some even died from drinking bacteria-contaminated “raw milk”.  In Pennsylvania, the production and sale of dairy products including “raw milk” is closely regulated and requires a permit.  Retention of a permit requires submitting to inspections and passing periodic herd and product testing.  Despite the dangers, many consumers continue to buy “raw milk” from farms without permits.  These sales are like a ticking time bomb.  The bad publicity from an outbreak of food-borne illness traced back to a dairy product—even if it originated in an “outlaw” operation—could decimate sales throughout the industry.  Because just one sloppy farm selling “raw milk” could instantly erode consumer confidence and cause an industry-wide collapse of the market resulting in a loss of millions of dollars in sales, it is a deeply concerning issue.

Enter the backyard chicken—a two-fold source of anxiety for the poultry industry and its regulators.  Like unregulated meat and dairy products, eggs and meat from backyard poultry flocks are often marketed without being monitored for the pathogens responsible for the transmission of food-borne illness.  From the viewpoint of the poultry industry, this situation poses a human health risk that in the event of an outbreak, could erode consumer confidence, not only in homegrown organic and free-range products, but in the commercial line of products as well.  Consumers can be very reactive upon hearing news of an outbreak, recalling few details other than “the fowl is foul”— then refraining from buying poultry products.  The second and currently most concerning source of trepidation among members of the poultry industry though is the threat of avian flu and other diseases being harbored in and transmitted via flocks of backyard birds.

The Green Revolution, the post-World War II initiative that integrated technology into agriculture to increase yields and assure an adequate food supply for the growing global population, brought changes to the way farmers raised poultry for market.  Small-scale poultry husbandry slowly disappeared from many farms.  Instead, commercial operations concentrated birds into progressively-larger indoor flocks to provide economy of scale.  Over time, genetics and nutrition science have provided the American consumer with a line of readily available high-quality poultry products at an inexpensive price.  Within these large-scale operations, poultry health is closely monitored.  Though these enclosures may house hundreds of thousands of birds, the strategy during an outbreak of communicable disease is to contain an outbreak to the flock therein, writing it off so to speak to prevent the pathogens from finding their way into the remainder of the population in a geographic area, thus saving the industry at the expense of the contents of a single operation.  Adherence to effective biosecurity practices can contain outbreaks in this way.

An offshoot of the Green Revolution, a large-scale poultry operation.
Modern science has produced a genetic map of the domestic chicken (Gallus gallus domesticus) allowing faster development of varieties with improved disease resistance, productivity, and other traits.  (United States Department of Agriculture image by Peggy Greb)
A technician checks eggs produced by immunized birds for the presence of flu virus.  A flu vaccine could provide an added layer of protection to biosecurity in the poultry industry.  (United States Department of Agriculture image by Stephen Ausmus)

The renewed popularity of backyard poultry is a reversal of the decades-long trend towards reliance on ever-larger indoor operations for the production of birds and eggs.  But backyard flocks may make less-than-ideal neighbors for commercial operations, particularly when birds are left to roam outdoors.  Visitors to properties with roaming chickens, ducks, geese, and turkeys may pick up contamination on their shoes, clothing, tires, and equipment, then transmit the pathogenic material to flocks at other sites they visit without ever knowing it.  Even the letter carrier can carry virus from a mud puddle on an infected farm to a grazing area on a previously unaffected one.  Unlike commercial operations, hobby farms frequently buy, sell, and trade livestock and eggs without regard to disease transmission.  The rate of infection in these operations is always something of a mystery.  No state or county permits are required for keeping small numbers of poultry and outbreaks like avian flu are seldom reported by caretakers of flocks of home-raised birds, though their occurrence among them may be widespread.  The potential for pathogens like avian flu virus circulating long-term among flocks of backyard poultry in close proximity to commercial houses is a real threat to the industry.

Live poultry and eggs are frequently sold to and traded among operators of backyard flocks without monitoring for disease.  (United States Department of Agriculture image by Keith Weller.)

There are a variety of motivations for tending backyard poultry.  While for some it is merely a form of pet keeping, others are more serious about the practice—raising and breeding exotic varieties for show and trade.  Increasingly, backyard flocks are being established by people seeking to provide their own source of eggs or meat.  For those with larger home operations,  supplemental income is derived from selling their surplus poultry products.  Many of these backyard enthusiasts are part of a movement founded on the belief that, in comparison to commercially reared birds, their poultry is raised under healthier and more humane conditions by roaming outdoors.  Organic operators believe their eggs and meat are safer for consumption—produced without the use of chemicals.  For the movement’s most dedicated “true believers”, the big poultry industry is the antagonist and homegrown fowl is the only hope.  It’s similar to the perspective members of the “raw milk” movement have toward pasteurized milk.  True believers are often willing to risk their health and well-being for the sake of the cause, so questioning the validity of their movement can render a skeptic persona non grata.

What’s in your eggs?  (United States Department of Agriculture image by Peggy Greb)

For the consumer, the question arises, “Are eggs and poultry from the small-scale operations better?”

While many health-conscious animal-friendly consumers would agree to support the small producer from the local farm ahead of big business, the reality of supplying food for the masses requires the economy of scale.  The billions of people in the world can’t be fed using small-scale and/or organic growing methods.  The Green Revolution has provided record-high yields by incorporating herbicides, insecticides, plastic, and genetic modification into agriculture.  To protect livestock and improve productivity, enormous indoor operations are increasingly common.  Current economics tell the story—organic production can’t keep up with demand, that’s why the prices for items labelled organic are so much higher.

A commercial poultry operation (in this case turkeys) produces economical consumer products.  (United States Department of Agriculture image by Scott Bauer)

To the consumer, buying poultry raised outdoors is an appealing option.  Compared to livestock crowded into buildings, they feel good about choosing products from small operations where birds roam free and happy in the sunshine.

An outdoor flock of backyard chickens.  (United States Department of Agriculture Animal and Plant Inspection Service image)

But is the quality really better?  Some research indicates not.  Salmonella outbreaks have been traced back to poultry meat sourced from small unregulated operations.  Studies have found dioxins in eggs produced by hens left to forage outdoors.  The common practice of burning trash can generate a quantity of ash sufficient to contaminate soils with dioxins, chemical compounds which persist in the environment and in the fatty tissue of animals for years.  The presence of elevated levels of dioxins in eggs from outdoor grazing operations may pose a potential consumer confidence liability for the entire egg industry.

Birds raised or kept in an outdoor zoo or backyard poultry setting can be susceptible to viruses and other pathogens when wild birds including vultures and hawks become attracted to the captives’ food and water when it is placed in an accessible location.  In addition, hunting and scavenging birds are opportunistic— attracted to potential food animals when they perceive vulnerability.  Selective breeding under domestication has rendered food poultry fat, dumb, and too genetically impaired for survival in the wild.  These weaknesses instantly arouse the curiosity of raptors and other predators whose function in the food web is to maintain a healthy population of animals at lower tiers of the food chain by selectively consuming the sickly and weak.  In settings such as those created by high-intensity agriculture and urbanization, wild birds may find the potential food sources offered by outdoor zoos and backyard poultry irresistible.  As a result they may perch, loaf, and linger around these locations—potentially exposing the captive birds to their droppings and transmission of bird flu and other diseases.

Variation produced under domestication has left poultry unfit for life among the perils found outdoors.  (United States Department of Agriculture image)
Turkey Vulture and White-tailed Deer
Millions of years of natural selection have made scavengers and predators ideally suited for the role of detecting and consuming dead, dying, and diseased wild animals, thus reducing accumulations of rotting carcasses and the spread of infectious pathogens among prey species.  Their distribution and reproductive success is closely controlled by the availability of food.  Humans need not disturb this balance or create unnatural congregations of these animals by providing supplemental foods such as dead poultry.

While outdoor poultry operations usually raise far fewer birds than their commercial counterparts, their animals are still kept in densities high enough to promote the rapid spread of microbiological diseases.  Clusters of outdoor flocks can become a reservoir of pathogens with the capability of repeatedly circulating disease into populations of wild birds and even into commercial poultry operations—threatening the industry and food supply for millions of people.  For this reason, state and federal agencies are encouraging operators to keep backyard poultry indoors—segregated from natural and anthropogenic disease vectors and conveyances that might otherwise visit and interact with the flock.

BACK TO THE FUTURE?—NOT LIKELY

The hobby farmer, the homesteader, the pet keeper, and the consumer seldom realize what the modern farmer is coming to know—domestic livestock must be segregated from the sources of contamination and disease that occur outdoors.  Adherence to this simple concept helps assure improved health for the animals and a safer food supply for consumers.  In the future, outdoor production of domestic animals, particularly those used as a food supply, is likely to be classified as an outdated and antiquated form of animal husbandry.

Outside and Inside Animals
It’s as simple as ABC and 123.
Cage-free chickens can be housed within the protective envelop of a building where they can be segregated from the microbes and pollutants found outdoors.  The U.S.D.A. defines “free-range” poultry as birds with some access to an outdoor setting where the benefits of biosecurity and quarantine are, for all intents and purposes, nullified.  (United States Department of Agriculture image by Stephen Ausmus)
Pigs
Pigs raised outdoors by homesteaders and hobby farmers pose the threat of spreading a number of diseases including Swine Fevers and Brucellosis into pork industry operations.   Escaped individuals are often attracted to commercial hog houses where they can loiter outside and contaminate the ground surrounding entrance ways used by personnel tending the animals.  Like other domestic animals, pigs should be contained inside buildings for biosecurity.
Dairy cows in an indoor feed lot.
Dairy cows and other cattle raised within well-designed indoor and semi-indoor settings are less prone to injury and consumption of contaminated foods and water.
Domestic Cat
Domestic Cats (Felis catus), particularly when allowed to roam outdoors, can contract the parasite Toxoplasma gondii during interactions with mice.  Humans, dogs, pigs, and other animals coming in contact with the Toxoplasma oocysts shed in feline feces can contract Toxoplasmosis, a disease with various physical and mental health symptoms.  According to the Centers for Disease Control, there are approximately three million cases of Toxoplasmosis among humans in the United States annually.

THE THREAT FROM PRIONS

If there are three things the world learned from the SARS CoV-2 (Covid-19) epidemic, it’s that 1) eating or handling bush meat can bring unwanted surprises, 2) dense populations of very mobile humans are ideal mediums for uncontrolled transmission of disease, and 3) quarantine is easier said than done.

If you think viruses are bad, you don’t even want to know about prions.  Prions are a prime example of why now is a good time to begin housing domestic animals, including pets, indoors to segregate them from wildlife.  And prions are a good example of why we really ought to think twice about relying on wild animals as a source of food.  Prions may make us completely rethink the way we interact with animals of any kind—but we had better do our thinking fast because prions turn the brains of their victims into Swiss cheese.

Stained slide of cow brain tissue affected by Bovine Spongiform Encephalopathy (BSE). The pale-colored air pockets are voids in the tissue caused by the disease.  (United States Department of Agriculture image by the late Dr. Al Jenny)

Diseases caused by prions are rapidly progressing neurodegenerative disorders for which there is no cure.  Prions are an abnormal isoform of a cellular glycoprotein.  They are currently rare, but prions, because they are not living entities, possess the ability to begin accumulating in the environment.  They not only remain in detritus left behind by the decaying carcasses of afflicted animals, but can also be shed in manure—entering soils and becoming more and more prevalent over time.  Some are speculating that they could wind up being man’s downfall.

The  Centers for Disease Control lists these human afflictions caused by prions…

The Centers for Disease Control lists these prion-caused ailments of other animals…

Dairy cows in a pasture.
Bovine Spongiform Encephalopathy (BSE), also known as Mad Cow Disease, is a neurodegenerative disorder fatal to cattle.  It is caused by the same prion that, when consumed or otherwise contracted by humans, causes Creutzfekd-Jokob Disease (CJD).
Chronic Wasting Disease (CWD), a fatal disease caused by a prion, is currently spreading among populations of the White-tailed Deity in the mid-Atlantic region.  Prions are understood to be folded proteins, not living things, thus they are not destroyed by cooking and other disinfection practices.  If you are wondering whether various forms of these pathogens will begin accumulating in the environment and affecting more and more species with new and more frightening afflictions, well, time will tell.  Meanwhile, we at susquehannawildlife.net are staying away from “game” and any other form of bush meat.  Thanks, but no thanks!
The future with a safe food supply will require domestic animals to be contained indoors while wildlife roams unmolested outdoors.

SOURCES

Schoeters, Greet, and Ron Hoogenboom.  2006.  Contamination of Free-range Chicken Eggs with Dioxins and Dioxin-like Polychlorinated Biphenyls.  Molecular Nutrition and Food Research.  (10):908-14.

Szczepan, Mikolajczyk, Marek Pajurek, Malgorzata Warenik-Bany, and Sebastian Maszewski.  2021.  Environmental Contamination of Free-range Hen with Dioxin.  Journal of Veterinary Research.  65(2):225-229.

U.S.D.A. Animal and Plant Inspection Service.  2022 Confirmations of Highly Pathogenic Avian Influenza.  aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/2022-hpai-commercial-backyard-flocks as accessed January 14, 2023.

U.S.D.A. Animal and Plant Inspection Service.  2022 Confirmations of Highly Pathogenic Avian Influenza.  aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/2022-hpai-wild-birds  as accessed January 14, 2023.

Bald Eagles Arriving at Conowingo Dam

You need to see this to believe it—dozens, sometimes hundreds, of Bald Eagles doing their thing and you can stand or sit in just one place to take it all in.

Conowingo Dam on the Susquehanna River near Darlington, Maryland, attracts piscivores galore.  Young Gizzard Shad (Dorosoma cepedianum) and other small fishes are temporarily stunned as they pass through the turbines and gated discharges at the hydroelectric facility’s power house.  Waiting for them in the rapids below are predatory fishes including Striped Bass (Morone saxatilis), White Perch (Morone americana), several species of catfishes, and more.  From above, fish-eating birds are on the alert for a disoriented turbine-traveler they can easily seize for a quick meal.

U.S. Route 1 crosses the Susquehanna River atop the Conowingo Dam.  Conowingo Fisherman’s Park, the observation site for the dam’s Bald Eagles and other birds, is located downstream of the turbine building along the river’s west (south) shore.  As the name implies, the park is a superb location for angling.
Heed this warning.  Close your windows and sunroof or the vultures will subject your vehicle’s contents to a thorough search for food.  Then they’ll deposit a little consolation prize on your paint.
Scavenging Black Vultures congregate by the hundreds at Conowingo Dam to clean up the scraps left behind by people and predators.  They’ll greet you right in the parking lot.
Photographers line up downstream of the turbine building for an opportunity to get the perfect shot of a Bald Eagle.
The operator of the Conowingo Hydroelectric Generating Station, Exelon Energy, provides clean comfortable facilities for fishing, sightseeing, and wildlife observation.
There’s almost always a Peregrine Falcon zooming around the dam to keep the pigeons on their toes.
Double-crested Cormorants on the boulders that line the channel below the dam.  Hundreds are there right now.
Double-crested Cormorants dive for fish near the power house discharge, which, while just one small generator is operating, seems nearly placid.  The feeding frenzy really gets going when Conowingo begins generating with multiple large turbines and these gently flowing waters become torrential rapids filled with disoriented fishes.
Ring-billed Gulls seek to snag a small fish from the water’s surface.
After successfully nabbing shad or perch, these Double-crested Cormorants need to swallow their catch fast or risk losing it.  Stealing food is a common means of survival for the gulls, eagles, and other birds found here.
Where do migrating eagles go?  There are, right now, at least 50 Bald Eagles at Conowingo Dam, with more arriving daily.  Numbers are likely to peak during the coming weeks.
Eagles can be seen perched in the woods along both river shorelines, even in the trees adjacent to the Conowingo Fisherman’s Park car lot.  Others take stand-by positions on the boulders below the dam.
To remind visiting eagles that they are merely guests at Conowingo, a resident Bald Eagle maintains a presence at its nest on the wooded slope above Fisherman’s Park.  Along the lower Susquehanna, female Bald Eagles lay eggs and begin incubation in January.
When an eagle decides to venture out and attempt a dive at a fish, that’s when the photographers rush to their cameras for a chance at a perfect shot.
The extraordinary concentrations of Bald Eagles at Conowingo make it an excellent place to study the plumage differences between birds of various ages.
Here’s a first-year Bald Eagle, also known as a hatch-year or juvenile bird.
A second-year or Basic I immature Bald Eagle.  Note the long juvenile secondaries giving the wings a ragged-looking trailing edge.
A third-year or Basic II immature Bald Eagle.
A second-year/Basic I immature Bald Eagle (top) and a third-year/Basic II immature Bald Eagle (bottom).
A second-year/Basic I immature Bald Eagle (bottom) and a third-year/Basic II immature Bald Eagle (top).  Note the white feathers on the backs of eagles in these age classes.
A third-year/Basic II immature Bald Eagle perched in a tree alongside the parking area.  Note the Osprey-like head plumage.
A sixth-year or older adult Bald Eagle in definitive plumage (left) and a fourth-year or Basic III immature Bald Eagle (right).
If you want to see the Bald Eagles at Conowingo Dam, don’t wait.  While many birds are usually present throughout the winter, the large concentrations may start dispersing as early as December when eagles begin wandering in search of other food sources, particularly if the river freezes.
A pair of Bald Eagles is already working on a nest atop this powerline trestle downstream of Conowingo Dam.  By late December, most adult eagles will depart Conowingo to begin spending their days establishing and defending breeding territories elsewhere.  Any non-adult eagles still loitering around the dam will certainly begin receiving encouragement from the local nesting pair(s) to move along as well.

To reach Exelon’s Conowingo Fisherman’s Park from Rising Sun, Maryland, follow U.S. Route 1 south across the Conowingo Dam, then turn left onto Shuresville Road, then make a sharp left onto Shureslanding Road.  Drive down the hill to the parking area along the river.  The park’s address is 2569 Shureslanding Road, Darlington, Maryland.

As Bald Eagle numbers continue to increase, expect the parking lot to become full during weekends and over the Thanksgiving holiday.  To avoid the crowds, plan to visit during a weekday.

You can get the generating schedule for the Conowingo Dam by calling the Conowingo Generation Hotline at 888-457-4076.  The recording is updated daily at 5 P.M. to provide information for the following day.

A Visit to Waggoner’s Gap

Nothing beats spending a day at a hawk watch lookout—except of course spending a day at a hawk watch lookout when the birds are parading through nonstop for hours on end.

Check out Waggoner’s Gap, a hawk count site located on the border of Cumberland and Perry Counties atop Blue Mountain just north of Carlisle, Pennsylvania.  It is by far the Lower Susquehanna River Watershed’s best location for observing large numbers of migrating raptors during the October and November flights.

Waggoner’s Gap is located where Route 74 crosses Blue Mountain north of Carlisle.
The entrance to a parking area for hawk watch visitors is designated by this sign located along Route 74 several hundred yards north of the summit of Blue Mountain.
Since acquiring the site in 2000, Audubon Pennsylvania has added improvements to expand the function of Waggoner’s Gap Hawk Watch to include education for both formal students and the public at large.
The site is named in honor of the late conservationist Clifford L. Jones, a business leader, a former Chairman of the Pennsylvania Public Utilities Commission, a cabinet secretary for six Pennsylvania governors (both major parties), a director on the boards of numerous conservation organizations, and an active birder.
Orange falcon silhouettes function as blazes for the trails that lead from the parking area to the lookout.  The trail and the lookout consist entirely of boulders.  Some of these move when stepped upon.  Others may be slick.  Use caution at all times.
The lookout at Waggoner’s Gap is staffed by official counters from August through December each year.  They are tasked with enumerating every migratory raptor’s passage during that period.
Sure-footed observers climb into a comfortable position among the Tuscarora quartzite boulders and begin watching the flight.
The view from the lookout is spectacular.  To the east, downtown Harrisburg can be seen in the distance.
During a recent afternoon with breezes from the “southwesterlies”, a steady stream of  migrating Sharp-shinned Hawks, including this juvenile, passed by the lookout.
Sharp-shinned Hawks were ready subjects for photography as they sailed on updrafts along the south side of the ridge.
An adult Sharp-shinned Hawk.
A second-year Sharp-shinned Hawk.
A Sharp-shinned Hawk below eye level.  Over 400 Sharp-shinned Hawks migrated past Waggoner’s Gap Hawk Watch on this particular early October day.
The local Turkey Vultures at Waggoner’s Gap seem ubiquitous at times.  They’re on the radio towers, they’re flying overhead, and a few are cruising the slopes below the crest.  But on the day of our recent visit, their numbers were eclipsed by the more than 300 “T.V.s” that migrated down the ridge.
Black Vultures, both migrants and local birds, are seen from the lookout.
Northern Harriers are a hawk watch favorite.  Their long uptilted wings, long tail, and white rump make them easy to identify, even for beginners.  Their plummeting numbers make them a treasured sighting for everyone.
A Red-tailed Hawk on a close approach.
A distant Red-shouldered Hawk.  Numbers of these migrants peak later in the season.
A Peregrine Falcon darts past the lookout.  Note the white forehead, throat, and breast.  This bird is probably a “Tundra Peregrine” (Falco peregrinus tundrius).  In the lower Susquehanna valley, this subspecies is strictly migratory, a transient in spring and fall.  “Tundra Peregrines” breed in the arctic and winter as far south as South America.
An immature Bald Eagle.  Waggoner’s Gap is a superb place for sighting eagles, especially on a breezy day.
Hundreds of Blue Jays filtered through as their southbound exodus continues.  Other songbirds of interest included Blue-headed Vireos (Vireo solitarius), Winter Wrens, Red-breasted Nuthatches, Pine Siskins, and both Ruby-crowned and Golden-crowned Kinglets.

Waggoner’s Gap is a hardy birder’s paradise.  During the latter portion of the season, excellent flights often occur on days that follow the passage of a cold front and have strong northwest winds.  But be prepared, it can be brutal on those rocks during a gusty late-October or early-November day after the leaves fall—so dress appropriately.

To see the daily totals for the raptor count at Waggoner’s Gap Hawk Watch and other hawk watches in North America, and to learn more about each site, be sure to visit hawkcount.org

Winter Won’t Let Go…the Birds Don’t Care

It seems as though the birds have grown impatient for typical spring weather to arrive.  The increase in hours of daylight has signaled them that breeding time is here.  No further delays can be entertained.  They’ve got a schedule to keep.

Thursday, March 29:  Winds began blowing from the southwest, breaking a cold spell which had persisted since last week’s snowfall.  Birds were on the move ahead of an approaching rainy cold front.

Friday, March 30:  Temperatures reached 60 degrees at last.  Birds were again moving north through the day, despite rain showers and a change in wind direction—from the northwest and cooler following the passage of the front in the late morning.

Flocks of Double-crested Cormorants followed the Susquehanna River north in numerous V-shaped flocks during the recent several days.
There were Turkey Vultures by the hundreds on the way north.
And nearly as many Black Vultures too.

Saturday, March 31:  It was cooler, but birds were still on the wing headed north.

At sunrise, a migrating Northern Flicker stopped by at a suet feeder to refuel.

Osprey pairs have arrived at nest sites on the lower Susquehanna.

Sunday, April 1:  The morning was pleasant, but conditions became cooler and breezy in the afternoon.  Migratory and resident birds began feeding ahead of another storm.

A distant flock of fast-flying Bonaparte’s Gulls (Chroicocephalus philadelphia) moves expeditiously up the Susquehanna at Conewago Falls as winds begin to pick up during the late morning.  Are they hurrying to get north of the path of the forthcoming weather system?
A Mourning Dove (Zenaida macroura) feeds in anticipation of a snowy night ahead.
A male Downy Woodpecker devours a late-afternoon meal.
This Tufted Titmouse (Baeolophus bicolor), a cavity-nesting species, is distracted by a potential new home.
Dark-eyed Juncos winter in the lower Susquehanna valley.  During the month of April, they will begin departing for their breeding grounds, some nesting in the mountains just to our north.
Tufted Titmouse…still house hunting.
A male American Goldfinch is progressing through molt into a showy breeding (alternate) plumage.
A male House Finch takes a break from its melodious song to feed before the arrival of our next spring snow.  His mate is already incubating eggs in a nest not far away.
Northern Cardinals (Cardinalis cardinalis) feed through the late afternoon, often as the last birds out-and-about before darkness.  This male remains close to his mate as she forages beneath nearby shrubs.

Monday, April 2: Snow fell again, overnight and through the morning—a couple of inches.  Most of the snow had melted away by late afternoon.

Horned Larks are plentiful in large open bare-soil (tilled) farmlands in winter, particularly near fresh manure.  Their sandy-tan coloration hides them well, and they are seldom noticed unless spotted at roadside following snow storms.  Horned Larks are migratory ground-nesting birds found in many sparsely vegetated habitats including tundra, parched fields and prairies, beaches, and even airports.  There is a breeding population in the lower Susquehanna valley which may be increasingly attracted to favorable nesting habitat created in some no-till fields, possibly using a window of opportunity between the demise of cold-season cover crops and the ascendency of the warm-season crops to complete a brood cycle.  Comparing the site selection and success rates of nesting Horned Larks under various crop management methods, including reactions to herbicide use, could be an enlightening study project for inquisitive minds. (Hint-Hint)
The dainty Chipping Sparrow has arrived. This species commonly nests in small trees, often in suburban gardens.

A Flock of Seagulls?

At the moment there is a heavy snow falling, not an unusual occurrence for mid-February, nevertheless, it is a change in weather.  Forty-eight hours ago we were in the midst of a steady rain and temperatures were in the sixties.  The snow and ice had melted away and a touch of spring was in the air.

Big Bluestem in the Riverine Grasslands is inundated by the rising waters of the Susquehanna at Conewago Falls.   The river ice has been dispersed by the recent mild temperatures and rains.

Anyone casually looking about while outdoors during these last several days may have noticed that birds are indeed beginning to migrate north in the lower Susquehanna valley.  Killdeer, American Robins, Eastern Bluebirds, Red-winged Blackbirds, and Common Grackles are easily seen or heard in most of the area now.

Just hours ago, between nine o’clock this morning and one o’clock this afternoon, there was a spectacular flight of birds following the river north, their spring migration well underway.  In the blue skies above Conewago Falls, a steady parade of Ring-billed Gulls was utilizing thermals and riding a tailwind from the south-southeast to cruise high overhead on a course toward their breeding range.

Ring-billed Gulls swarm in a thermal updraft above Conewago Falls to gain altitude prior to streaming off to the north and continuing their journey.
Ring-billed Gulls climbing to heights sometimes exceeding 1,000 feet before breaking off and gliding away to the north.

The swirling hoards of Ring-billed Gulls attracted other migrants to take advantage of the thermals and glide paths on the breeze.  Right among them were 44 Herring Gulls, 3 Great Black-backed Gulls, 12 Tundra Swans (Cygnus columbianus), 10 Canada Geese, 3 Northern Pintails (Anas acuta), 6 Common Mergansers, 3 Red-tailed Hawks, a Red-shouldered Hawk, 6 Bald Eagles (non-adults), 8 Black Vultures, and 5 Turkey Vultures.

A first-year Herring Gull (top center) is a standout in a “kettle” of Ring-billed Gulls.
How many Ring-billed Gulls passed by today?  More than 18,000…with emphasis on MORE THAN.  You see, early this afternoon, the handy-dandy clicker-counter used to tick off and tally the big flights of birds as they pass by quit clicking and counting.  Therefore, 18,000 is the absolute minimum number of Ring-billed Gulls seen migrating north today.  Hopefully the trusty old oil can will get the clicker working again soon.

In the afternoon, the clouds closed in quickly, the flight ended, and by dusk more than an inch of snow was on the ground.  Looks like spring to me.

Migrating North?

CLICK ON THE LOGO FOR TODAY’S MIGRATION COUNT TOTALS

A steady stream of birds was on the move this morning over Conewago Falls.  There were hundreds of Ring-billed Gulls, scores of Herring Gulls, and a few Great Black-backed Gulls to dominate the flight.  Then too there were thirteen Mallards, Turkey Vultures and a Black Vulture, twenty or more American Robins, a half a dozen Bald Eagles (juvenile and immature birds), a couple of Red-winged Blackbirds, and, perhaps most unusual of all, a flock of a dozen Scoters (Melanitta species), a waterfowl typical of the Mid-Atlantic surf in winter.  All of these birds were diligently following the river, and into a headwind no less.

“Hold on just a minute there, buster,” you may say, “I’ve looked at the migration count by dutifully clicking on the logo above and there is nothing but zeroes on the count sheet for today.  The season totals have not changed since the previous count day!”

Ah-ha, my dedicated friend, correct you are.  It seems that today’s bird flight was solely in one direction.  And that direction was upriver, moving north into a north breeze, on a heading which conflicts with all logic for creatures that should still be headed south for winter.  As a result, none of the birds observed today were counted on the “Autumn Migration Count”.

You might say, “Don’t you know that Winter Solstice was three days ago, so autumn and autumn migration is over.”

Okay, point well taken.  I should therefore clarify that what we title as “Autumn Migration Count” is more accurately a census of birds, insects, and other creatures transiting from northerly latitudes to more favorable latitudes to the south for winter.  This transit can begin as early as late June and extend into the first weeks of winter.  While most of this movement is motivated by the reduced hours of daylight during the period, late season migrants are often responding to ice, bad weather, or lack of food to prompt a journey further south.  Migration south in late December and January occurs even while the amount of daylight is increasing slightly in the days following the Winter Solstice.

So what of the birds seen flying north today?  There was some snow cover that has melted away, and the ice that formed on the river a week ago is gone due to the milder than normal temperatures this week.

One may ask, “Were the birds seen today migrating north?”

Let’s look at the species seen moving upriver today a try to determine their motivation.

First, and perhaps most straight-forward, is the huge flight of gulls.  Wintering gulls on the Susquehanna River near Conewago Falls tend to spend their nights in flocks on the water or on treeless islands and rocky outcrops in the river.  Many hundreds, sometimes thousands, find such favorable sites along the fifteen mile stretch of river from Conewago Falls downstream to Lake Clarke and the Conejohela Flats at Washington Boro.  Each morning most of these gulls venture out to suburbia, farmland, landfill, hydroelectric dams, and other sections of river in search of food.  Gulls are very able fliers and easily cover dozens of miles outbound and inbound each day in search of food.  Many of the gulls seen this morning were probably on their way to the Harrisburg metropolitan area to eat trash.  Barring any extraordinary buildups of ice on this section of river, one would expect these gulls to remain and make these daily excursions to food sources through early spring.

Ring-billed Gulls fly upriver through the Pothole Rocks at Conewago Falls.
Herring Gulls stream upriver through Conewago Falls on their way to fine dining.

Second, throughout the season Bald Eagles have been tallied on the migration count with caution.  Flight altitude, behavior, plumage, and the reaction of the “local” eagles to these transients was carefully considered before counting an eagle as a migrant.  They roam a lot, particularly when young, and range widely to feed.  The movement of eagles up the river today was probably food related.  A gathering of adult, juvenile, and immature Bald Eagles could be seen more than a half mile upstream from the migration count lookout.  Those moving up the river seemed to assemble with the “locals” there throughout the morning.  White-tailed Deities occasionally drown, particularly when there is thin or unstable ice on the river (as there was last week) and they attempt to tread upon it.  Then, their bodies are often stranded among rocks, in trees, or on the crown of the dam.  After such a mishap, their carcasses become meals for carrion-eaters in the falls.  Such an unfortunate deity, or another source of food, may have been attracting the eagles in numbers today.

A distant gathering of Bald Eagles at the south end of Three Mile Island in upper Conewago Falls.

Next, Black and Turkey Vultures often roam widely in search of food.  The small numbers seen headed up-river today would tend to mean very little when trying to determine if there is a trend or population shift.  Again, food may have been luring them upriver from nearby roosts.

And finally, the scoters, Mallards, American Robins, and Red-winged Blackbirds may have been wandering as well.  Toward mid-day, the wind speed picked up and the direction changed to the east.  This raises the possibility that these and others of the birds seen today may sense a change in weather, and may seek to take flight from the inclement conditions.  Prompted by the ocean breeze and in an attempt to avoid a storm, was there some movement away from the Atlantic Coastal Plain to the upper Piedmont today?  Many species may make these types of reactive movements.  Is it possible that some birds flee or avoid ever-changing storm tracks and alter there wintering locations based on jet streams, water currents, and other climatic conditions?  Probably.  These are interesting dynamics and something worthy of study outside the simpler methods of a migration count.

A Ring-billed Gull begins feeding as storm clouds approach Conewago Falls at mid-day.  This and other gull species travel widely in their winter range to find food and safe roosting sites.  For them, northward spring migration usually begins no earlier than late February.

Conewago Lineman

…And if it snows that stretch down south won’t ever stand the strain…                                                                  –Jimmy Webb

The lower Susquehanna valley’s first snowfall of the season arrived yesterday.  By this morning it measured just an inch in depth at Conewago Falls, more to the south and east, less to the west and north.  By mid-morning a cold fresh to moderate breeze from the northwest was blowing through the falls and stirring up ripples on the river.

Light snow on the Conewago Falls Pothole Rocks this morning.

Gulls sailed high overhead on the wind, taking a speedy ride downriver toward Chesapeake Bay, the Atlantic coast, and countless fast-food restaurant parking lots where surviving winter weather is more of a sure thing.  Nearly a thousand Ring-billed Gulls soared past the migration count lookout today.  Thirteen Herring Gulls and four Great Black-backed Gulls were among them.

Other migrants today included a Mallard, twenty-nine American Black Ducks, two Bald Eagles, eleven Black Vultures, fifteen Turkey Vultures, five American Goldfinches, and fifteen Red-winged Blackbirds.  The wintery weather seems to be prompting these late-season travelers to be on their way.

CLICK ON THE LOGO FOR TODAY’S MIGRATION COUNT TOTALS

You know, today was like many other days at the falls.  As I arrive, I have the habit of checking all the power line towers on both river shorelines to see what may be there awaiting discovery.  More often than not, something interesting is perched on one or more of the structures…

…sometimes there are large flocks of European Starlings…
…other times there might be one or more Turkey Vultures…
…or possibly a Bald Eagle or two…
…or maybe the fastest-flying bird on the planet…
…or perhaps, wait; what’s he doing up there?

Yes friends, while the birds migrated through high above, down below a coordinated effort was underway to replace some of the electric transmission cable that stretches across the Susquehanna River at Conewago Falls.  As you’ll see, this project requires precise planning, preparation, and skill.  And it was fascinating to watch!

A helicopter is used to raise/lower men and equipment to/from the top of the towers.
A crew doing preparation work is lifted from a tower on the west shore of Conewago Falls.
A crew member is raised to a tower on the east shore of Conewago Falls to begin the next phase of the project.
Crew members are positioned on the two towers on the west shore.
The helicopter hovers in a stand-by position above the Pothole Rocks.  By keeping the chopper downwind from and below the wires being replaced, the pilot avoids putting rotor wash into the work area.   Note the linemen on the upper left side of each tower.  These men monitored the pulleys as the old cable, followed by the new, was pulled from the west shore to the east.
At the ready, the pilot skillfully hovers his craft, nose into the gusty wind, just 100 feet to the east of the migration count site on the Pothole Rocks.
Even as the chopper maintained position near and immediately over the count lookout, migrating birds continued to be seen streaming in a downriver direction high above.
A migrating immature Bald Eagle passes overhead, apparently undaunted by the commotion created by the use of a helicopter to tend the crew advancing replacement wire across the river below.
With the new cable in place, workers are lifted from the towers and lowered to the ground where they can get out of the cold wind after a job well done.

Culinary Reminder

It was a crisp clear morning with birdless blue skies.  The migration has mostly drawn to a close; very little was seen despite a suitable northwest breeze to support a flight.   There were no robins and no blackbirds.  Not even a starling was seen today.  The only highlights were a Bufflehead (Bucephala albeola) and a couple of Swamp Sparrows.

A Swamp Sparrow is coaxed from the dense leafy cover of the Riverine Grasslands of Conewago Falls.
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And now ladies and gentlemen, boys and girls, it’s time for a Thanksgiving Day culinary reminder from the local Conewago Falls Turkey…

“That’s the Conewago Falls Turkey Vulture if you don’t mind.  And I’m here to remind you that this Thanksgiving, you don’t have to fight your way in there to get first pickings of the feast.  Take it from me, let those flavors and aromas intensify over time.  And juices, who needs juices?  Let that stuff congeal so everything sticks to your ribs.  Are you paying attention?  I’m telling you, just back off, let the crowd die down, then get in there and devour those leftovers.  They’re the best.  You’ll thank me later!”

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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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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