Photo(s) of the Day

A tallgrass prairie wildflower and warm-season grass planting: Big Bluestem
This tallgrass prairie wildflower planting on a health campus in Hershey, Pennsylvania, enhances stormwater management and benefits butterflies and other wildlife.  Reducing the acreage maintained as manicured lawn has helped disperse the large flocks of resident Canada Geese (a population of invasive native transplants) that frequented the property and posed a serious hazard to medevac helicopters flying in and out of the facility.
A tallgrass prairie wildflower and warm-season grass planting
Big Bluestem, a warm-season grass, dominates the site and is complemented by Indiangrass and tall wildflowers including Common Milkweed, Wild Bergamot, Oxeye, Black-eyed Susan, Prairie Coneflower, and Purple Coneflower.

A Tufted Duck at Middle Creek

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”.

Birds/Waterfowl of Conewago Falls in the Lower Susquehanna River Watershed: Tufted Duck
The male Tufted Duck (right) with a male Ring-necked Duck (left).
Birds/Waterfowl of Conewago Falls in the Lower Susquehanna River Watershed: Tufted Duck
This male Tufted Duck has been seen in the company of Ring-necked Ducks and other waterfowl on this pond located opposite the small white shed along Hopeland Road in the Lebanon County section of the Middle Creek W.M.A.  It has also been seen on other nearby ponds and, when the Hopeland Road pond is frozen, on the main lake near Willow Point.
Birds/Waterfowl of Conewago Falls in the Lower Susquehanna River Watershed: Tufted Duck
A Canada Goose, an American Wigeon, and the rare Tufted Duck.  If you want to see the Tufted Duck’s “tuft”, you’ll need to remember your binoculars or, better yet, a spotting scope.

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.

Common Goldeneyes, Buffleheads, and Migrating Canada Geese

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.

At the Veteran’s Memorial Bridge, the Susquehanna was cresting this morning after recent rains and accompanying snow melt.
An overnight breeze from the southwest and calm winds during the morning hours created ideal conditions for flocks of Canada Geese to begin migrating north from Chesapeake Bay through the lower Susquehanna valley.
These three Common Mergansers and a Common Goldeneye (right) are some of the hundreds of diving ducks presently gathered on the river in the vicinity of the Veteran’s Memorial Bridge.
Common Goldeneyes and a first-winter male Bufflehead (upper right).  All of the ducks seen today in the waters surrounding the bridge are benthic feeders, diving to the river bottom to pluck invertebrates from the substrate.
A male Common Goldeneye (Bucephala clangula).
A female Common Goldeneye.
A pair of Common Goldeneyes in flight.
A pair of Buffleheads in flight.
Common Goldeneyes repositioning for another series of feeding dives.
During the morning flight, thousands of Canada Geese were seen moving north in flocks numbering about 50 to 100 birds each.  The bird in the lower right was one of thousands of Ring-billed Gulls seen headed upriver as well.
As they pass over the lower Susquehanna region, migrating Canada Geese are typically observed flying much higher than flocks from the local resident populations, often reaching the cruising altitudes of aircraft.  Aviators are always alert for flights of resident geese around airfields.  But to prevent bird strikes during days like today when thousands of migratory geese traverse the airspace, air traffic controllers can become extra busy relaying the location and altitude of potential targets to pilots flying aircraft entering areas where birds have been reported.

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.

Snow Geese Arriving

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?

Hundreds of high-flying Snow Geese descended onto the main lake at Middle Creek Wildlife Management Area this afternoon.
Snow Geese and a few Ring-necked Ducks as seen from the Willow Point observation area at Middle Creek this afternoon.
The sound of calling Tundra Swans is music to the ears on an otherwise quiet winter day.
Dozens of Common Mergansers are at Middle Creek W.M.A. right now.
Look carefully and you might see American Black Ducks among the waterfowl in the refuge’s impoundments.
Northern Shovelers have been at Middle Creek since late fall.  If they can continue to access the muddy bottom of the refuge’s lake for food, they’ll stay until the spring migration.
Check those flocks of Canada Geese carefully, sometimes you’ll find something different among them,…
…like this noticeably smaller bird, probably either a Lesser Canada Goose (Branta canadensis parvipes) or a Richardson’s Cackling Goose (Branta hutchinsii hutchinsii).

Don’t just sit there—don your coat, grab a pair of binoculars, and get out and have a gander!

City Life: Gulls, Dabbling Ducks, and More

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.

From the middle of the Susquehanna River, City Island offers a spectacular view of the downtown Harrisburg skyline.  In summer, it’s the capital city’s playground.  During the colder months, it’s a great place to take a quiet walk and find unusual birds.
This Bald Eagle was in mature trees along the river shoreline near the Harrisburg Senator’s baseball stadium.
Ring-billed Gulls gather on the “cement beach” at the north end of City Island.
One of a dozen or so Herring Gulls seen from the island’s north end. This particular bird is a juvenile.
A Ring-billed Gull and some petite Bonaparte’s Gulls.  Really good birders will tell you to always check through flocks of these smaller gulls carefully.  It turns out they’re onto something.  Look closely at the gull to the right.
A bright red bill and more of a crescent shape to the black spot behind the eye, that’s an adult Black-headed Gull (Chroicocephalus ridibundus) in winter plumage, a rare bird on the Susquehanna.  Black-headed Gulls have colonized North America from Europe, breeding in Iceland, southernmost Greenland, and rarely Newfoundland.

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.

A flock of Killdeer at the south end of Wildwood Lake.  From November through February, a walk along the south and west sides of the impoundment can be a photographer’s dream. The light is suitable in the morning, then just keeps getting better as the day wears on.
Is this probable Carolina/Black-capped Chickadee hybrid a resident at Wildwood or just a visitor from a few miles to the north?  Currently, pure Black-capped Chickadees (Poecile atricapillus) nest in the mountains well to the north of Harrisburg, and pure Carolina Chickadees nest south of the city.  Harrisburg possibly remains within the intergrade/hybrid zone, an area where the ranges of the two species overlap, but probably not for long.  During recent decades, this zone has been creeping north, at times by as much as a half mile or more each year.  So if the capital city isn’t Carolina Chickadee territory yet, it soon will be.
Another chickadee likely to be a hybrid, this one with some white in the greater wing coverts like a Black-capped, but with a call even more rapid than that of the typical Carolina, the species known for uttering the faster “chick-a-dee-dee-dee”.  It sounded wired, like it had visited a Starbucks all morning.
In the lower Susquehanna valley, Carolina Chickadees have already replaced hybrids and pure Black-capped Chickadees as nesting birds in the Piedmont hills south of Harrisburg and the Great Valley.  This Carolina Chickadee was photographed recently in the Furnace Hills at Middle Creek Wildlife Management Area in northern Lancaster County.  The transition there was probably complete by the end of the twentieth century.  Note the characteristic overall grayish appearance of the wings and the neat lower border of the black bib on this bird, 
For comparison, a bird presumed to be a pure Black-capped Chickadee photographed earlier this month in Lebanon County, Pennsylvania.  This fall, “Black-caps”, like many other northern perching birds, are moving south to invade the lower elevations and milder climes of the Piedmont and Atlantic Coastal Plain Provinces.  Note the extensive areas of white in the wings, the long tail, the buffy flanks, and the jagged edge of the black bib.
Along Wildwood Lake’s west shore, an adult male Sharp-shinned Hawk was soon attracted to the commotion created by bantering chickadees and other songbirds.
Yellow during the first year, the eyes of the Sharp-shinned Hawk get redder as the bird ages.
Also along the west border of Wildwood Lake, temperatures were warm enough to inspire Painted Turtles (Chrysemys picta) to seek a sun bath atop logs in the flooded portions of the abandoned Pennsylvania Canal.

And now, without further ado, it’s time for the waterfowl of Wildwood Lake—in order of their occurrence.

A pair of Wood Ducks (hen left, drake right) with American Black Ducks and Canada Geese.
A pair of Northern Pintails.
A pair of American Wigeons (Mareca americana).
A hen (left) and drake (right) Gadwall.
Mallards.
A female Northern Shoveler.
An American Black Duck.
Canada Geese.
You just knew there had to be a booby prize, a “Blue Suede” (a.k.a. Blue Swede), a domestic variety of Mallard.
It’s a Green-winged Teal (Anas crecca) sampler.  Clockwise from left: a juvenile male, a female, and an adult male.
A drake and two hen Green-winged Teal.  Isn’t that great light by late afternoon?

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.

SOURCES

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.

Really Bad Poetry

Nothing says Happy Valentine’s Day like a really bad poem, so here it is…

 

FOR THE LOVE OF DUCKS

 

I like to feed the duckies

Try it and you’ll see

Aren’t they really lucky?

Relying just on me

 

My neighbors are complainin’

I can hear them talk

The mallards eat their garden

Let surprises on their walk

 

Dung stains on the carpets

They tracked it in the house

It’s from those ducks and not the pets

Can’t blame it on the spouse

 

I like to feed the duckies

Try it and you’ll see

Aren’t they really lucky?

Relying just on me

 

Tamed with bread and crackers

I gave them as a treat

I soon found maimed dead quackers

Lying in the street

 

A driver who intended

To miss the hens and drakes

Had their car rear-ended

When they hit the brakes

 

I like to feed the duckies

Try it and you’ll see

Aren’t they really lucky?

Relying just on me

 

The flock is very wasteful

Each bird a pound a day

Web-foots in a cesspool

Pollute the waterway

 

There are some kids playing

In that filthy ditch

Soon they’ll be displaying

The rash of Swimmer’s Itch

 

I like to feed the duckies

Try it and you’ll see

Aren’t they really lucky?

Relying just on me

 

These ducks they do not migrate

They’re here day in, day out

Aquatic life they decimate

No plants, no fish, no trout

 

Hurry! Hurry! Heed my call

Before it starts to rain

Ten more ducklings took a fall

And are stranded in a drain

 

I like to feed the duckies

Try it and you’ll see

Aren’t they really lucky?

Relying just on me

 

Have you people lost your minds?

I see you by your fence

These ducks are cute and I am kind

It’s you who’ve lost your sense

 

Beggars from the handouts

My God what have I done?

Their senseless habits leave no doubt

Their instincts are all gone

 

I like to feed the duckies

Try it and you’ll see

Aren’t they really lucky?

Relying just on me

 

Now I know just what to do

Like one would teach a child

I’ll feed the ducks at the zoo

And let the rest live wild

 

So if you feed the duckies

Beware of the spell

Or you will do the same as me

Loving ducks to death as well

 

—Ducks Anonymous, LLC

 

They’re cute, but if you really love waterfowl, then please refrain from feeding them.  Hand-fed ducks soon lose their survival instincts.  These clueless birds do dumb things like loiter in traffic and, perhaps worst of all, omit migration from their yearly life cycle.  Daily plundering by year-round congregations of Canada Geese, Mute Swans, polygamous Mallards (seen here), and domestic waterfowl is decimating native plant and animal populations in waterways, wetlands, ponds, and lakes throughout the Lower Susquehanna River Watershed.  For aquatic food chains and fisheries to recover, people must stop feeding (and releasing) these highly-impressionable birds.

Clean Slate for 2020

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.

The 2019 bird list included 48 species, the 47 on the board plus Ruby-throated Hummingbird, which was logged on a slip of paper found tucked into the edge of the frame.

This Green Frog, photographed on New Year’s Day 2019, was “out and about” along the edge of the editor’s garden pond.  Due to the recent mild weather, Green Frogs were active during the current New Year’s holiday as well.
On a day with strong south winds in late February or during the first two weeks of March, there is often a conspicuous northbound spring flight of migrating waterfowl, gulls, and songbirds that crosses the lower Susquehanna valley as it departs Chesapeake Bay.  These Tundra Swans were among the three thousand seen from the garden patio on March 13, 2019.  A thousand migrating Canada Geese, 500 Red-winged Blackbirds, numerous Ring-billed Gulls, and some Herring Gulls were seen during the same afternoon.
This juvenile Cooper’s Hawk was photographed through the editor’s kitchen window.  From its favorite perch on this arbor it would occasionally find success snagging a House Sparrow from the large local flock.  It first visited the garden in November, the species being absent there since early spring.  Unlike previous years, there was no evidence of a breeding pair in the vicinity during 2019.
Plantings that provide food and cover for wildlife are essential to their survival.  Native flowers including Trumpet Vine (Campsis radicans) and Partridge Pea provide nourishment for the Ruby-throated Hummingbirds that visit the editor’s garden, but they really love a basket or pot filled with Mexican Cigar (Cuphea ignea) too.  The latter (seen here) can be grown as a houseplant and moved outdoors to a semi-shaded location in summer and early fall.  But remember, it’s tropical, so you’ll need to bring it back inside when frost threatens.
A Swamp Sparrow is an unusual visitor to a small property surrounded by paved parking lots and treeless lawns.  Nevertheless, aquatic gardens and native plants helped to attract this nocturnal migrant, seen here eating seeds from Indiangrass.  It arrived on September 30 and was gone on October 2.

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.

The Tufted Titmouse was a daily visitor to the garden through 2018.  This one was photographed investigating holes in an old magnolia there during the spring of that year.  There were no Tufted Titmouse sightings in the garden in 2019.  This and other resident species, especially cavity-nesters, appear to be experiencing at least a temporary decline.
Breeding birds including Northern Cardinals may have had a difficult year.  In the editor’s garden, a pair were still feeding and escorting one of their young in early October.  The infestation of the editor’s town by domestic house and feral cats may have contributed to the failure of earlier broods, but a lack of food is also a likely factor.

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.

At about the time of summer solstice in June each year, Common Grackles begin congregating into roving summer flocks that will grow in size to assure their survival during the autumn migration, winter season, and return north in the spring.  From his garden, the editor saw just one flock of less than a dozen birds during the summer of 2019.  He saw none during his journeys through other areas of the Susquehanna valley.  Flocks of one hundred birds or more did not materialize until the southbound movements of grackles passed through the region in October and November.

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.

A clean slate for 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.

Tundra Swan Migration

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.

Tundra Swans flying northwest, paralleling the Susquehanna five miles distant.
Tundra Swans winter on the Atlantic Coastal Plain and often stage their northbound movements on the Piedmont along the lower Susquehanna River and at the nearby Middle Creek Wildlife Management Area.  The birds seen this evening are possibly coming directly from the coast or Chesapeake Bay.  With five hours of favorable wind helping them along, covering one hundred miles or more in an afternoon would be no problem.
High-flying Tundra Swans on their way to breeding grounds on, you guessed it, the arctic tundra in Alaska and northwestern Canada.
Tundra Swans in the largest flocks, sometimes comprised of more than 200 birds, were often detected by their vocalizations as they approached.
Tundra Swan flights continued after sunset and nightfall.
All of the high-flying migratory Canada Geese seen this evening were on a more northerly course than the northwest-bound swans.  These geese probably spent the winter on the Atlantic Coastal Plain near Chesapeake Bay and are now en route to breeding grounds in, you guessed it again, Canada.  They are not part of the resident Canada Goose population we see nesting throughout the lower Susquehanna valley.

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.

 

It is the First Full Day of Spring…Isn’t It?

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.

Common Grackles are often the first perching birds to begin moving north through the lower Susquehanna valley in spring.  They often winter in large roving flocks of mixed blackbird species on the nearby Atlantic Coastal Plain Province.  These flocks sometimes wander the farmlands of the lower Piedmont Province near the river, but rarely stray north of the 40th parallel before February.

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.

Tundra Swans will migrate in a northwest direction to reach breeding grounds west and north of Hudson Bay.
Migratory Canada Geese departing the Chesapeake Bay area typically pass over the lower Susquehanna valley at high altitudes.  A south wind can bring a sustained day-long flight of migrating geese and ducks over the region on a given day in late-February or March.
Snow Geese (Chen caerulescens) historically wintered in the marshes of the Atlantic seaboard where the tide cycle kept vegetation primarily snow-free for feeding.  Removal of hedgerows and intensive farming since the 1980s has attracted these birds to inland agricultural lands during their preparation for the move north.  For nearly three decades, tens of thousands have annually begun their spring journey with a stopover at the Middle Creek Wildlife Management Area.  Flocks range widely from Middle Creek to feed, commonly as far west as the fields of the Conewago Creek valley in the Gettysburg Basin to the east of Conewago Falls.  
American Black Ducks
A pair of Northern Shovelers (Anas clypeata).
Ring-necked Ducks (Aythya collaris) are “diving ducks”.
A male Lesser Scaup, Aythya affinis, (front center) and Ring-necked Ducks (rear and left) seen between feeding dives.
A male Bufflehead (Bucephala albeola).  These miniature diving ducks will sometimes winter on the Susquehanna in “rafts” of dozens of birds.
Tundra Swans journey toward the “Land of the Mid-Night Sun”.

 

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.

Strangers In The Night

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 high-flying migratory Canada Goose can be seen during the daytime and heard at night when passing over the lower Susquehanna River valley.  A large flight exiting from Chesapeake Bay in late February or early March often results in a 12 to 24 hour-long stream of northbound flocks.

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.

National Oceanic and Atmospheric Administration/National Weather Service radar image from May 5, 2010, at 11:18 PM EDT, shows rain associated with a cold front moving east from the border of Ontario, Canada, and the United States into New England and the Mid-Atlantic region.  The heavy blue and green reflections surrounding the radar locations ahead of the front are nocturnal migrating birds taking advantage of favorable conditions for flight including a tail wind from the southwest.  Note the lighter migration behind the advancing front.  Heavy radar echoes on the gulf coast, particularly in Texas, indicate dense bird concentrations exiting the tropics to fan out into North American breeding areas.  The westward progression of expanding echoes surrounding individual radar sites indicates birds rising into the radar beam at local nightfall.

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.

National Oceanic and Atmospheric Administration/National Weather Service radar image (still) from September 5, 2017, at 2:38 AM EDT, shows rain in the northeast associated with a slow-moving cold front stretching from Maine southwest to New Mexico.  Heaviest nocturnal bird flights can be seen behind the advancing front where there are favorable tail winds from the north or northwest.
Nearly two full days later, the slow-moving cold front from the previous image has crossed Pennsylvania.  As nightfall progresses from east to west, ascending nocturnal migrants enter NEXRAD radar beams, their echoes creating expanding rings around individual sites.  Concentrations of southbound birds can be seen along the gulf coast.  Many will follow the Texas coastline into Mexico.  The Neotropical migrants that try to cross the Gulf of Mexico this night could be in for a perilous voyage.  Hurricane Katia is churning in the southern gulf and a much stronger storm, Hurricane Irma, is rolling toward the Bahamas and Florida from the southeast.  Masses of birds that follow learned routes or instinct to venture offshore and cross seas under such circumstances could suffer catastrophic losses.  (NOAA/National Weather Service image)

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.

SOURCES

Clemson University Radar Ornithology Laboratory (CUROL) website:   http://virtual.clemson.edu/groups/birdrad/    as accessed September 6, 2017.