If you’re like us, you’re forgoing this year’s egg hunt due to the prices, and, well, because you’re a little bit too old for such a thing.
Instead, we took a closer look at some of our wildlife photographs from earlier in the week. We’ve learned from experience that we don’t always see the finer details through the viewfinder, so it often pays to give each shot a second glance on a full-size screen. Here are a few of our images that contained some hidden surprises.
..but upon closer inspection we located…
..but after zooming in a little closer we found…
..but then, following further examination, we discovered…
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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…
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.
With large crowds of observers stopping by at the Pennsylvania Game Commission’s Middle Creek Wildlife Management Area to view the thousands of migrating Snow Geese and Tundra Swans there, you may not notice the smaller but just as enthusiastic crowd gathering at the refuge to see a single, rather inconspicuous waterfowl, a male Tufted Duck (Aythya fuligula). This extraordinarily rare visitor has been on the refuge for at least two weeks now. The Tufted Duck, a diving benthic feeder, is native to Europe and Asia, but this vagrant individual seems to be comfortable in the company of its North American counterparts, a flock of Ring-necked Ducks. Birders known as “listers” relish the chance to see such an unusual find. Many are traveling from bordering states for a chance to add it to their list of species observed during their lifetime—their “life list”.
Want to start a “life list” of bird sightings? Just get out a piece of paper or start a document on your computer and jot down the name of the bird and the date and location where you saw it for the first time. That’s all there is to it. Beginning a “life list” can be the start of a lifelong passion. And a Tufted Duck wouldn’t be too shabby as the first “lifer” on your list.
Spring migration is underway and waterfowl are on the move along the lower Susquehanna River. Here is a sample of sightings collected during a walk across the Veteran’s Memorial Bridge at Columbia-Wrightsville this morning.
This is, of course, just the beginning of the great spring migration. Do make a point of getting out to observe the spectacle. And remember, keep looking up—you wouldn’t want to miss anything.
With plenty of open water on the main lake and no snow cover on the fields where they graze, Snow Geese have begun arriving at Middle Creek Wildlife Management Area in Lancaster/Lebanon Counties. As long as our mild winter weather continues, more can be expected to begin moving inland from coastal areas to prepare for their spring migration and a return to arctic breeding grounds.
You probably need a break from being indoors all month, so why not get out and have a look?
Don’t just sit there—don your coat, grab a pair of binoculars, and get out and have a gander!
So you aren’t particularly interested in a stroll through the Pennsylvania woods during the gasoline and gunpowder gang’s second-biggest holiday of the year—the annual sacrifice-of-the-White-tailed-Deity ritual. I get it. Two weeks and nothing to do. Well, why not try a hike through the city instead? I’m not kidding. You might be surprised at what you see. Here are some photographs taken today during several strolls in Harrisburg, Pennsylvania.
First stop was City Island in the Susquehanna River—accessible from downtown Harrisburg or the river’s west shore by way of the Market Street Bridge.
Okay, City Island was worth the effort. Next stop is Wildwood Park, located along Industrial Road just north of the Pennsylvania Farm Show complex and the Harrisburg Area Community College (HACC) campus. There are six miles of trails surrounding mile-long Wildwood Lake within this marvelous Dauphin County Parks Department property.
And now, without further ado, it’s time for the waterfowl of Wildwood Lake—in order of their occurrence.
See, you don’t have to cloak yourself in bright orange ceremonial garments just to go for a hike. Go put on your walking shoes and a warm coat, grab your binoculars and/or camera, and have a look at wildlife in a city near you. You never know what you might find.
Taylor, Scott A., Thomas A. White, Wesley M. Hochachka, Valentina Ferretti, Robert L. Curry, and Irby Lovette. 2014. “Climate-Mediated Movement of an Avian Hybrid Zone”. Current Biology. 24:6 pp.671-676.
Inside the doorway that leads to your editor’s 3,500 square foot garden hangs a small chalkboard upon which he records the common names of the species of birds that are seen there—or from there—during the year. If he remembers to, he records the date when the species was first seen during that particular year. On New Year’s Day, the results from the freshly ended year are transcribed onto a sheet of notebook paper. On the reverse, the names of butterflies, mammals, and other animals that visited the garden are copied from a second chalkboard that hangs nearby. The piece of paper is then inserted into a folder to join those from previous New Year’s Days. The folder then gets placed back into the editor’s desk drawer beneath a circular saw blade and an old scratched up set of sunglasses—so that he knows exactly where to find it if he wishes to.
A quick glance at this year’s list calls to mind a few recollections.
Before putting the folder back into the drawer for another year, the editor decided to count up the species totals on each of the sheets and load them into the chart maker in the computer.
Despite the habitat improvements in the garden, the trend is apparent. Bird diversity has not cracked the 50 species mark in 6 years. Despite native host plants and nectar species in abundance, butterfly diversity has not exceeded 10 species in 6 years.
It appears that, at the very least, the garden habitat has been disconnected from the home ranges of many species by fragmentation. His little oasis is now isolated in a landscape that becomes increasingly hostile to native wildlife with each passing year. The paving of more parking areas, the elimination of trees, shrubs, and herbaceous growth from the large number of rental properties in the area, the alteration of the biology of the nearby stream by hand-fed domestic ducks, light pollution, and the outdoor use of pesticides have all contributed to the separation of the editor’s tiny sanctuary from the travel lanes and core habitats of many of the species that formerly visited, fed, or bred there. In 2019, migrants, particularly “fly-overs”, were nearly the only sightings aside from several woodpeckers, invasive House Sparrows (Passer domesticus), and hardy Mourning Doves. Even rascally European Starlings became sporadic in occurrence—imagine that! It was the most lackluster year in memory.
If habitat fragmentation were the sole cause for the downward trend in numbers and species, it would be disappointing, but comprehendible. There would be no cause for greater alarm. It would be a matter of cause and effect. But the problem is more widespread.
Although the editor spent a great deal of time in the garden this year, he was also out and about, traveling hundreds of miles per week through lands on both the east and the west shores of the lower Susquehanna. And on each journey, the number of birds seen could be counted on fingers and toes. A decade earlier, there were thousands of birds in these same locations, particularly during the late summer.
In the lower Susquehanna valley, something has drastically reduced the population of birds during breeding season, post-breeding dispersal, and the staging period preceding autumn migration. In much of the region, their late-spring through summer absence was, in 2019, conspicuous. What happened to the tens of thousands of swallows that used to gather on wires along rural roads in August and September before moving south? The groups of dozens of Eastern Kingbirds (Tyrannus tyrannus) that did their fly-catching from perches in willows alongside meadows and shorelines—where are they?
Several studies published during the autumn of 2019 have documented and/or predicted losses in bird populations in the eastern half of the United States and elsewhere. These studies looked at data samples collected during recent decades to either arrive at conclusions or project future trends. They cite climate change, the feline infestation, and habitat loss/degradation among the factors contributing to alterations in range, migration, and overall numbers.
There’s not much need for analysis to determine if bird numbers have plummeted in certain Lower Susquehanna Watershed habitats during the aforementioned seasons—the birds are gone. None of these studies documented or forecast such an abrupt decline. Is there a mysterious cause for the loss of the valley’s birds? Did they die off? Is there a disease or chemical killing them or inhibiting their reproduction? Is it global warming? Is it Three Mile Island? Is it plastic straws, wind turbines, or vehicle traffic?
The answer might not be so cryptic. It might be right before our eyes. And we’ll explore it during 2020.
In the meantime, Uncle Ty and I going to the Pennsylvania Farm Show in Harrisburg. You should go too. They have lots of food there.
There was a hint of what was to come. If you were out and about before dawn this morning, you may have been lucky enough to hear them passing by high overhead. It was 5:30 A.M. when I opened the door and was greeted by that distinctive nasal whistle. Stepping through the threshold and into the cold, I peered into the starry sky and saw them, their feathers glowing orange in the diffused light from the streets and parking lots below. Their size and snow-white plumage make Tundra Swans one of the few species of migrating birds you’ll ever get to visibly discern in a dark moonless nighttime sky.
The calm air at daybreak and through the morning transitioned to a steady breeze from the south in the afternoon. Could this be it? Would this be that one day in late February or the first half of March each year when waterfowl (and other birds too) seem to take advantage of the favorable wind to initiate an “exodus” and move in conspicuous numbers up the lower Susquehanna valley on their way to breeding grounds in the north? Well, indeed it would be. And with the wind speeding up the parade, an observer at a fixed point on the ground gets to see more birds fly by.
In the late afternoon, an observation location in the Gettysburg Basin about five miles east of Conewago Falls in Lancaster County seemed to be well-aligned with a northwesterly flight path for migrating Tundra Swans. At about 5:30 P.M., the clear sky began clouding over, possibly pushing high-flying birds more readily into view. During the next several hours, over three thousand Tundra Swans passed overhead, flocks continuing to pass for a short time after nightfall. There were more than one thousand Canada Geese, the most numerous species on similar days in previous years. Sometimes on such a day there are numerous ducks. Not today. The timing, location, and conditions put Tundra Swans in the spotlight for this year’s show.
Other migrants moving concurrently with the waterfowl included Ring-billed Gulls, Herring Gulls (6+), American Robins (50+), Red-winged Blackbirds (500+), and Common Grackles (100+).
Though I’ve only seen such a spectacle only once during a season in recent years, there certainly could be another large flight of ducks, geese, or swans yet to come. The breeze is forecast to continue from southerly directions for at least another day. Keep you eyes skyward, no matter where you might happen to be in the lower Susquehanna valley. These or other migratory species may put on another show, a “big day”, just for you.
You remember the signs of an early spring, don’t you? It was a mild, almost balmy, February. The earliest of the spring migrants such as robins and blackbirds were moving north through the Lower Susquehanna River Watershed. The snow had melted and ice on the river had passed. Everyone was outdoors once again. At last, winter was over and only the warmer months lie ahead…beginning with March.
Ah yes, March, the cold windy month of March. We remember February fondly, but this March has startled us out of our vernal daydreams to wrestle with the reality of the season. And if you’re anywhere near the Mid-Atlantic states on this first full day of spring, you know that a long winter’s nap and visions of sugar peas would be time better spent than a stroll outdoors. Presently it’s dusk, and the snow from the 4th “Nor’easter” in a month is a foot deep and still falling.
In honor of “The Spring That Was”, here then is a sampling of some of the migratory waterfowl that have found their way to the Lower Susquehanna River Watershed during March. Some are probably lingering and feeding for a while. All will move along to their breeding grounds within a couple of weeks, regardless of the weather.
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.
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.
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 (Cygnuscolumbianus), 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.
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.
We all know that birds (and many other animals) migrate. It’s a survival phenomenon which, above all, allows them to utilize their mobility to translocate to a climate which provides an advantage for obtaining food, enduring seasonal weather, and raising offspring.
In the northern hemisphere, most migratory birds fly north in the spring to latitudes with progressively greater hours of daylight to breed, nest, and provide for their young. In the southern hemisphere there are similar movements, these to the south during their spring (our autumn). The goal is the same, procreation, though the landmass offering sustenance for species other than seabirds is limited “down under”. Interestingly, there are some seabirds that breed in the southern hemisphere during our winter and spend our summer (their winter) feeding on the abundant food sources of the northern oceans.
Each autumn, migratory breeding birds leave their nesting grounds as the hours of sunlight slowly recede with each passing day. They fly to lower latitudes where the nights aren’t so long and the climate is less brutal. There, they pass their winter season.
Food supply, weather, the start/finish of the nesting cycle, and other factors motivate some birds to begin their spring and autumn journeys. But overall, the hours of daylight and the angle of the sun prompt most species to get going.
But what happens after birds begin their trips to favorable habitats? Do they follow true north and south routes? Do they fly continuously, day and night? Do they ease their way from point to point, stopping to feed along the way? Do they all migrate in flocks? Well, the tactics of migration differ widely from bird species to species, from population to population, and sometimes from individual to individual. The variables encountered when examining the dynamics of bird migration are seemingly endless, but fascinatingly so. Bird migration is well-studied, but most of its intricacies and details remain a mystery.
Consider for a moment that just 10,000 years ago, an Ice Age was coming to an end, with the southernmost edge of the most recent glaciers already withdrawn into present-day Canada from points as near as the upper Susquehanna River watershed. Back then, the birds migrating to the lower portion of the drainage basin each spring probably weren’t forest-dwelling tropical warblers, orioles, and other songbirds. The migratory birds that nested in the lower Susquehanna River valley tens of millennia ago were probably those species found nesting today in taiga and tundra much closer to the Arctic Circle. And the ancestors of most of the tropical migrants that nest here now surely spent their entire lives much closer to the Equator, finding no advantage by journeying to the frigid Susquehanna valley to nest. It’s safe to say that since those times, and probably prior to them, migration patterns have been in a state of flux.
During the intervening years since the great ice sheets, birds have been able to adapt to the shifts in their environment on a gradual basis, often using their unmatched mobility to exploit new opportunities. Migration patterns change slowly, but continuously, resulting in differences that can be substantial over time. If the natural transformations of habitat and climate have kept bird migration evolving, then man’s impact on the planet shows great potential to expedite future changes, for better or worse.
Now, let’s look at two different bird migration strategies, that of day-fliers or diurnal migrants, and that of night-fliers, the nocturnal migrants.
Diurnal migrants are the most familiar to people who notice birds on the move. The majority of these species have one thing in common, some form of defense to lessen the threat of becoming the victim of a predator while flying in daylight. Of course the vultures, hawks, and eagles fly during the day. Swallows and swifts employ speed and agility on the wing to avoid becoming prey, as do hummingbirds. Finches have an undulating flight, never flying on a horizontal plane, which makes their capture more difficult. Other songbirds seen migrating by day, Red-winged Blackbirds for example, congregate into flocks soon after breeding season to avoid being alone. Defense flocks change shape constantly as birds position themselves toward the center and away from the vulnerable fringes of the swarm. The larger the flock, the safer the individual. For a lone bird, large size can be a form of protection against all but the biggest of predators. Among the more unusual defenses is that of birds like Indigo Buntings and other tropical migrants that fly across the Gulf of Mexico each autumn (often completing a portion of the flight during the day), risking exhaustion at sea to avoid the daylight hazards, including numerous predators, found in the coastal and arid lands of south Texas. Above all, diurnal migrants capture our attention and provide a spectacle which fascinates us. Perhaps diurnal migrants attract our favor because we can just stand or sit somewhere and watch them go by. We can see, identify, and even count them. It’s fantastic.
What about a bird like the Canada Goose (Branta canadensis)? It is often seen migrating in flocks during the day (the truly migratory ones flying much higher than the local year-round resident “transplants”), but then, during the big peak movements of spring and fall, they can be heard overhead all through the night. Perhaps the Canada Goose and related waterfowl bridge the gap between day and night, introducing us to the secretive starlight and moonshine commuters, the nocturnal migrants.
The skies are sometimes filled with thousands of them, mostly small perching birds and waders. These strangers in the night fly inconspicuously in small groups or individually, and most can be detected when passing above us only when heard making short calls to remain in contact with their travel partners. They need not worry about predators, but instead must have a method of finding their way. Many, like the Indigo Bunting, can navigate by the stars, a capability which certainly required many generations to refine. The nocturnal migrants begin moving just after darkness falls and ascend without delay to establish a safe flight path void of obstacles (though lights and tall structures can create a deadly counter to this tactic). Often, the only clue we have that a big overnight flight has occurred is the sudden appearance of new bird species or individuals, on occasion in great numbers, in a place where we observe regularly. Just days ago, the arrival of various warbler species at Conewago Falls indicated that there was at least a small to moderate movement of these birds during previous nights.
In recent years, the availability of National Weather Service radar has brought the capability to observe nocturnal migrants into easy reach. Through the night, you can log on to your local National Oceanic and Atmospheric Administration’s National Weather Service radar page (State College for the Conewago Falls area) and watch on the map as the masses of migrating bird pass through the sweep of the radar beam. As they lift off just after nightfall, rising birds will create an echo as they enter the sweeping beam close to the radar site. Then, due to the incline of the transmitted signal and the curvature of the earth, migrants will be displayed as an expanding donut-like ring around the radar’s map location as returns from climbing birds are received from progressively higher altitudes at increasing distances from the center of the site’s coverage area. On a night with a local or regional flight, several radar locations may show signs of birds in the air. On nights with a widespread flight, an exodus of sorts, the entire eastern half of the United States may display birds around the sites. You’ll find the terrain in the east allows it to be well-covered while radars in the west are less effective due to the large mountains. At daybreak, the donut-shaped displays around each radar site location on the map contract as birds descend out of the transmitted beam and are no longer detected.
Weather systems sometimes seem to motivate some flights and stifle others. The first example seen below is a northbound spring exodus, the majority of which is probably migrants from the tropics, the Neotropical migrants, including our two dozen species of warblers. A cold front passing into the northeastern United States appears to have stifled any flight behind it, while favorable winds from the southwest are motivating a heavy concentration ahead of the front.
The second and third examples seen below are an autumn nocturnal migration movement, probably composed of many of the same tropics-bound species which were on the way north in the previous example. Note that during autumn, the cold front seems to motivate the flight following its passage. Ahead of the front, there is a reduced and, in places, undetectable volume of birds. The two images below are separated by about 42 hours.
You can easily learn much more about birds (and insects and bats) on radar, including both diurnal and nocturnal migrants, by visiting the Clemson University Radar Ornithology Laboratory (CUROL) website. There you’ll find information on using the various mode settings on NEXRAD (Next-Generation Radar) to differentiate between birds, other flying animals, and inanimate airborne or grounded objects. It’s superbly done and you’ll be glad you gave it a try.
Clemson University Radar Ornithology Laboratory (CUROL) website: http://virtual.clemson.edu/groups/birdrad/ as accessed September 6, 2017.