Sunday, February 25, 2018

February migrants

     I saw a few hundred Canada geese in a large, harvested corn field as I was driving along a country road in eastern Lancaster County, Pennsylvania farmland on February 23, 2018.  I stopped to watch the geese for a few minutes and noticed about a half dozen snow geese, with some of the Canada geese, on top of a small rise.  Thinking there could be more snow geese on the other side of that little hill, I drove to another rural road to see the geese from a different angle.  I counted 72 snow geese among more Canada geese in a shallow depression in that field.  All the geese of both species were resting when I saw them, but they probably had been feeding earlier on corn kernels.
     All winter I have been seeing flocks of Canadas most everywhere in Lancaster County cropland where they've been feeding on corn and the green shoots of winter rye.  But I'm sure other groups of Canada geese have recently arrived here from farther south and joined their locally over-wintering relatives in local fields to ingest vegetable matter.  And at this time, too, there are many thousands of snow geese resting and feeding at Middle Creek Wildlife Management Area.  The geese have seen the increasing periods of daylight each succeeding day and are restless to push north to their Arctic tundra breeding territories. 
    While watching the geese, I saw rivers of ring-billed gulls flowing across the sky, dropping like feathered waterfalls to the same corn field and a bordering rye field, and landing lightly on the ground.  There the gulls ate invertebrates emerging from the soil in the warm, wet weather and light rainfall.  Occasionally, a mass of gulls rose from the ground like a bed sheet being lifted by one corner, swirled over the fields a couple of times, then landed again where they rose just a minute ago.
     Many of these ring-bills had been feeding on edible garbage at nearby landfills all winter, but are now taking invertebrates from the fields.  And now those wintering gulls are being joined by relatives from Delaware and Chesapeake Bays and the Atlantic seacoast. 
     As I sat in my car along that lonely country road, I saw great, mixed masses of noisy blackbirds swarming over the fields and landing in that same harvested corn field the geese and gulls were in.  Exciting to see, the blackbirds came down to the field like a downpour of black rain drops.  Tens of thousands of blackbirds, including purple grackles, red-winged blackbirds and brown-headed cowbirds, must have been in those great gatherings that came together in one big horde in that corn field, making a part of that field dark with their tremendous numbers.  But those blackbirds, always restless, constantly shifted to different parts of the corn field and scattered into several smaller gatherings of themselves.  The attractive males and females of each kind walked briskly over dead corn stems and leaves still lying in the field and picked up corn kernels to choke down.  Then, suddenly, all the blackbirds took flight in a great, noisy mass again and disappeared from view in a twinkling.
     Typical of February and March migrants, those handsome geese, gulls and blackbirds, only six kinds in all, made my day.  Their spectacular numbers were thrilling to experience, though I have seen swarms of all those species many times before.  They are a bit of wildness in the human-made, cultivated habitats they adapted to, including farmland, impoundments and suburban areas.  However everyday they may be, those birds, and all of nature, are beautiful, intriguing, welcome miracles of God's nature on Earth.             

Thursday, February 22, 2018

Wintering River Ducks

     It is interesting and amazing to me how similar three kinds of ducks that winter on rivers and lakes in the Mid-Atlantic States are.  But not a surprise because American goldeneyes, buffleheads and common mergansers share (converge) on the same summer and winter habitats.  And goldeneyes and buffleheads are relatives in the same genus of ducks, but diverged a bit from a common ancestor.
     These three kinds of wintering ducks in southeastern Pennsylvania, as elsewhere, have many characteristics in common.  Drakes of these species have similar, striking dark and white colors and color patterns, mostly dark on top and white below.  The related and beautiful goldeneye and bufflehead drakes have almost identical color patterns.  However, male common mergansers are particularly handsome with iridescently green heads and blood-red beaks.  Hens of all three types are mostly brown, which camouflages them, including when they are raising ducklings.
     But these duck species have many more similarities.  They all nest by lakes and rivers in forests of Alaska and Canada, but not in the same places, though there is overlap.  Buffleheads raise young in southern Alaska and western Canada.  Goldeneyes hatch offspring in Alaska and across the middle of Canada from coast to coast.  And the mergansers rear ducklings across southern Alaska and southern Canada.
     Females of all three of these duck species hatch ducklings in tree cavities in northern woods, hollows created by woodpeckers and wind ripping limbs off trees, which exposes the inner wood to agents of decay.  Buffleheads, being small ducks, nest in abandoned flicker holes and similarly-sized tree hollows.  (Flickers are medium-sized woodpeckers.)  Goldeneyes hatch young in cavities that are larger than the ones buffleheads use, which reduces competition for nesting sites.  The mergansers lay eggs in still larger tree hollows.  Each species squeezes into as small an opening as it can to eliminate at least some predators.  The ducklings of each kind feed mostly on insects, which gives them much protein for growth.  However, when merganser young are a couple weeks old, they turn to eating small fish.    
     Buffleheads, American goldeneyes and common mergansers all winter on larger, open, inland waters, including fresh water rivers, lakes, and ponds in the case of the buffleheads.  They winter far enough south in the Lower 48 to be able to find open water to get their food. 
     Wintering buffleheads and goldeneyes dive gracefully under water to feed mostly on small crustaceans, mollusks, including snails, and insect larvae among stones on the bottoms of lakes and rivers.  Mergansers, however, slip under water to catch and ingest small fish during winter, as they do the rest of the year.  The different diet of the mergansers eliminates rivalry for food with buffleheads and goldeneyes, which allows all three species to be able to co-exist in the same habitats, summer and winter. 
     These striking, intriguing duck species that winter in southeastern Pennsylvania, and through much of the United States, wherever there is open water, have many characteristics and life styles in common because of their sharing summering and wintering habitats and niches.  And yet the precise niches of each kind allows it to live with reduced competition with the other species.  These ducks, like all forms of life, are truly remarkable in beauties and intrigues.   

Sunday, February 18, 2018

Thoughts About Crows

     I was driving through a part of Lancaster County, Pennsylvania farmland on February 16th and noticed a scattered flock of scores of crows feeding in fields harvested to the ground on both sides of the country road I was on.  About a dozen other crows were perched on roadside wires.  I stopped to see what the crows were doing and heard them cawing.  Judging from the tones of their voices, there were American crows and fish crows in the mixed flock, though I wouldn't have known that by sight alone.  Fish crows' cawing is more nasal than that of American crows.
     Thousands of American crows in large flocks have been in Lancaster County all winter, as in winters past.  They are some of the crows that nest in Canada's forests, but winter in the Lower 48 where food is more abundant and available in cropland in winter.  But these crows appeared smaller than the wintering Canadian crows, indicating they probably are locally-nesting crows that went farther south for the winter, but are now returning to raise young in local farmland. 
     In the last week I've noticed several crows moving, here and there, high across the sky from east to west over Lancaster County on migration to nesting territories.  And on February 15th, I saw a pair of crows investigating a few tall Norway spruce trees in our back yard, probably for a nesting site.  But, since they were completely silent, I don't know if they were American crows or fish crows. 
     But, getting back to the mixed gathering of crows in the fields and on roadside wires, I noticed about a half dozen of them eating something on the blacktop road.  With binoculars, I saw the "something" was a dead male American kestrel, without its head.  About that time, one crow flew with the dead body in its beak to the side of the road where that carcass could be devoured in relative safety from passing vehicles.
     Meanwhile, I saw that the six-foot-high banks on both sides of that stretch of rural road was riddled with small holes and runways in their soil; the works of field mice.  Apparently, the kestrel was perched on those same roadside wires to watch for field mice emerging from their burrows in the soil, as I have seen many kestrels do in the past.  Perhaps the kestrel dropped to a bank to catch a mouse, but was hit by a passing vehicle.  Or maybe the kestrel was caught and killed by a peregrine falcon or a Cooper's hawk, both of which hunt birds in Lancaster County's farmland.  Having been killed by a hawk would explain the absence of the kestrel's head as hawks often behead their prey.  The feeding peregrine or Coop might have been interrupted during its kestrel meal and dropped the dead bird onto the country road where the scavenging crows found it.
     I suspect the crows I saw on the 16th, and through the week before that date, were American crows and fish crows returning to Lancaster County and neighboring counties in southeastern Pennsylvania to rear offspring.  They might have been a bit earlier than usual this spring because, so far, we have had a mild winter here.  And I am sure they were not crows from Canada because they were smaller, were in farmland where the Canadian crows had not been all winter and the flock was partly composed of fish crows.       

Thursday, February 15, 2018

Wintering Coastal Sandpipers

     At first they appear to be mechanical toys running up windy, winter beaches before incoming, ocean wavelets, and down those beaches after outgoing wavelets along the Atlantic Ocean coast of the Mid-Atlantic States.  Then we realize they are a little flock of sandpipers called sanderlings that search the sand of ocean beaches for invertebrates washed-in with incoming waves through winter.
     Four kinds of sandpipers commonly winter along the Atlantic Ocean shoreline, including sanderlings, purple sandpipers, ruddy turnstones and dunlin.  Each species has its own winter niche that it's well adapted to, which reduces competition with its relatives for invertebrate food, though some overlapping occurs.  Each species is camouflaged in its niche, protecting those sandpipers from peregrine falcons, merlins and other kinds of aerial predators.  And each kind of sandpiper raises four young in a brood on the high Arctic tundra. 
     Wintering sanderlings are light in color, which blends them in with the nearly white sand.  Little groups of them here and there along the beaches are entertaining and amusing to watch running up and down that sandy habitat in each bird's quest for invertebrates: Their black legs are blurs of motion as they run.  And their stout beaks jab repeatedly at invertebrates in the sand as they quickly follow wavelets sliding down the beaches and out to sea, leaving many invertebrates behind in the sand.  If sanderlings are approached too closely, their little groups spring up into the wind and swirl with the wind down the beach to a more private spot to chase receding wavelets for invertebrates.
     Purple sandpipers winter along the Atlantic seacoast where it is strewn with boulders at the water line and where human-made jetties of boulders project into the ocean at right angles from beaches to protect bathing beaches along the Atlantic Ocean.  This type of sandpiper is dark, which makes individuals of this species difficult to see on dark, wave-battered rocks and boulders.  This species, generally, winters on those rock formations as individuals or in small gatherings.  Each sandpiper clings tightly to the wet, plant-covered boulders as it forages for invertebrates among those rocks regularly splashed with ocean water.  Obviously, sanderlings and purple sandpipers compete very little for food, which allows both those species to live along ocean shorelines, in different niches.    
     Ruddy turnstones winter in small gatherings on pebbly beaches and among jetties where they hunt invertebrates.  This species sometimes overlaps with sanderlings and purple sandpipers in each of their niches.  Turnstones are brown on top and white below with white markings in the brown that are visible when the birds fly away from us.  And this species has the habit of turning pebbles over with its stout bill to look for invertebrates under them.
     Dunlin winter in the largest flocks of these seacoast sandpipers.  Their niche, mostly, is mud flats when the tide is out in tidal salt marshes along ocean inlets and estuaries.  They are brown above, which camouflages them on mud flats while they probe their beaks rapidly into the mud to pull out invertebrates.
     As the mud of mud flats becomes exposed, big flocks of dunlin sweep onto those flats like grain tossed across them, disappearing to the naked eye when landing on the mud.  Right away they poke their bills into the mud to snare invertebrates.  But if disturbed, their large gatherings swirl rapidly up into the wind and zip away over the flats to watch for a more peaceful place to land and feed.  
     These species of sandpipers add much beauty, joy and inspiration to the Atlantic Ocean shore in the Middle Atlantic States in winter.  Watch for them when visiting the seacoast during that harshest of seasons. 

Monday, February 12, 2018

Early Spring

     Cold, ice and snow will strike southeastern Pennsylvania, as elsewhere, in February, but the look and feel of spring sometime in that month, depending a lot on the weather and the activities of certain, hardy birds and plants, can not be denied. 
     The first exhilerating, inspiring signs of spring's coming are visible around January 20th in this area.  Then daylight each succeeding day continues to be two minutes more than the day before as the sun "returns" to the northern hemisphere since December 22nd.  Toward the end of January, the sun is a little higher and hotter in the sky and sets a minute later each day, happily making longer periods of daylight each succeeding day.  Born from the chilly womb of winter, spring is coming.
     The sun "coming" north is caused by the Earth's tilting on its axis as it revolves around the sun.  When the northern hemisphere is tilted toward the sun, it is summer in that half of the world.  But when the northern hemisphere is pointed away from the sun, it is winter.
     Longer periods of daylight are registered in birds' brains and the ground is gradually warmed a bit, causing reactions in certain birds and plants by late January.  Thousands of big, hardy snow geese and tundra swans generally are the first birds to become restless and want to migrate north to their breeding grounds on the Arctic tundra.  But ice and snow farther north stop them.  So they push north a little, like to Lancaster County, Pennsylvania, and wait a few weeks on rivers, lakes and feeding fields for spring to catch up to their restless urges.  Mourning doves suddenly appear here in greater numbers than was seen earlier in January.  And the growing purple-streaked, green flower hoods of skunk cabbage in wooded swamps and green shoots of snow drops and winter aconites on lawns and flower beds poke through soil and leaves.  And each succeeding day still has more daylight than the one before.              
     Finally, the first day of spring arrives, according to my views based on the actions of birds and plants; this year (2018) on February 10, which is an average time each year.  By that time patches of snow drops and aconites are blooming, male mourning doves, northern cardinals, tufted titmice and a few other kinds of small, permanent resident birds are singing to establish nesting territories and attract mates, restless snow geese continue to increase their numbers locally, a few people have buckets on maple trees to collect their sap for boiling down to syrup and the daylight per day continues to get still longer. 
     Now, too, mated pairs of Canada geese and mallard ducks are noticeably looking for nesting places along waterways and impoundments.  And most every day at dusk from mid-February, through March and April, male American woodcocks present their elaborate courtship displays on the ground and in the sky above clearings near bottomland woods into the dark of night.  Only hunger or female woodcocks ready to mate interrupt the males' unique and entertaining performances.     
     I was in local woods on February 12th to enjoy the beautifully sunny, warm day.  The sun was "high" in the sky and bright and hot.  It was pleasurable to sit against a large tree, out of the cold wind, and soak up the warm sunlight.  A pair of Carolina chickadees peered at me in the woods and, suddenly, a tremendous flock of purple grackles flew overhead and landed in nearby treetops with much vocal squeaking.  That was the first large gathering of grackles I saw since late last summer, meaning these restless birds were pushing north to find food and be ready to start nesting colonies.        Toward the end of February, all the above plant and bird activities continue, and are joined by the swelling of gray, furry catkins on male pussy willow bushes.  Those catkins stand erect and become larger through the end of February and into March in this area.  Eventually, they turn yellow with pollen that is gathered by a small variety of early-spring insects.  Some of those insects are eaten by a variety of small birds.
     Early spring is an exciting, inspiring time of year to me; one of my favorite times of year.  A surprising number of plant and animal species respond to the early increase in daylight per day and slight rise in average temperatures.  They suddenly appear in southeastern Pennsylvania where they had not been visible all winter, or at least in small numbers in the case of swans and geese.  But one must get out and look for the subtle, inspiring signs of early spring.  They are not always evident until one searches for them.       

Wednesday, February 7, 2018

Birches of Eastern Pennsylvania

     Four species of birch trees are native to eastern Pennsylvania, including black birches, yellow birches, river or red birches and gray birches.  Each kind is adapted to a specific habitat apart from its relatives.  And being related, all these birches have characteristics in common, some of which are attractive to us, making these trees worth experiencing. 
     All birch species have wind-pollinated catkins that grow early in spring before the birches' leaves do.  Male catkins are about two inches long and pendulous, while female ones on the same tree are about one inch long and upright. 
     Birches have small, cone-like structures where the female catkins were and where tiny, winged seeds develop by autumn.  Each seed has a wing on each side, making it look like a tiny butterfly.  And those two wings together carry the seed on the wind away from parent trees for maximum dispersal. 
     Birch trees feed a variety of wildlife.  Many seeds are eaten by mice and small, seed-eating birds.  White-tailed deer, snowshoe hares and cottontail rabbits ingest buds and twigs, particularly in winter.  And beavers consume the bark and twigs of birch trees, as well as using those trees to make their dams and lodges.  
     Black birches have smooth, shiny bark, with noticeable, horizontal lenticles in that bark when they are young.  Bark on older trees, however, develops vertical cracks and irregular, scaly plates, especially on their trunks.  And chewed twigs of this species have a pleasant wintergreen fragrance and taste that can be savored when hiking over wooded hills. 
     Black birches are most common on rocky, wooded slopes where they are associates of chestnut oak trees, red oaks, sugar maples and other deciduous, upland tree species.  In fact, black birches and chestnut oaks dominate many wooded, rocky hillsides in eastern Pennsylvania, such as Governor Dick Mountain near Mt. Gretna.
     Yellow birch trees inhabit cool, wooded ravines where cold streams and brooks flow through.  They are associates of eastern hemlocks in many of those woodland valleys.  This birch has thin, pale-yellow bark that peels away from trunks and limbs in tight curls.  Those curls, even when wet, can be used to start campfires because of the resin in them.  And their twigs have a hint of wintergreen scent and taste.  Sapsuckers, which are a kind of woodpecker, punch holes in the soft bark of this birch and later come back to lap the sugary sap that drips from those wounds in the bark. 
     Some yellow birches look like they grew on "stilts", which is interesting to see.  Those birches on poles are caused by seedling yellow birches sprouting on stumps and fallen logs.  As the yellow birches grew tall and put roots into the ground, the wood of the stumps and logs rotted away, leaving those birches on stilts.
     River birches, also called red birches because of the color of their loose bark, have thin bark that peels away profusely from trunks and branches, giving the trees a shaggy, but attractive, appearance.  River birches have been planted on many lawns because of their rustic, intriguing bark.
     As their name implies, river birches are adapted to bottomlands along creeks and rivers, where they are associates of sycamores, and ash-leafed and silver maple trees.  All those tree species, and more, help hold the soil down against erosion, and feed and shelter wildlife as well.
     Gray birches have chalky-white or grayish-white bark, with dark triangles where limbs protrude from trunks, making these birches attractive.  They are so striking that gray birches are planted on some lawns. 
     Gray birches have adapted to pioneering dry, rocky, poor soil where they are associates of large-toothed aspens and scrub pines.  These three species of trees colonize land abandoned after farming or mining fails, and when fires burned down forests.  Many gray birches have pioneered slag heaps from mining along Route 81, just south of the Pocono Mountains, for example.  In fact, they seem to be the only tree on some of those waste piles from mining.  
     All the birch species are lovely trees that also provide food for wildlife.  And through divergent evolution, each kind has its own habitat, which spreads the various species into different niches, thus reducing competition for soil, rainfall and sunlight with their relatives.          

Saturday, February 3, 2018

Decorative Riparian Trees

     For a couple of hours on the cold, windy afternoon of February 2 of this year, I explored a quarter mile long stretch of deciduous woodland along a creek in northeastern Lancaster County, Pennsylvania to observe nature.  I was impressed with the variety of decorative, bottomland trees in that narrow woods in winter, including sycamores, river birches, ash-leafed maples, shag-bark hickories, pin oaks and swamp white oaks.  Since those trees were all bare of foliage, a visit to that woodland was more enjoyable because I could see the trees' different beauties
     Sycamore trees have mottled light and pale-gray bark that allows them to stand out in riparian woods.  When pieces of the older, gray bark fall away, the lighter, newer bark is visible, causing the mottling on trunks and branches.  The light-colored bark of sycamore trees lining streams and creeks can be seen from a distance and indicates where those waterways are in the distant landscape.
     Sycamores also have many round seed balls that hang decoratively on long stems from the tips of twigs through much of winter.  The tiny seeds float away on the wind and some of them sprout in areas of moist soil along waterways.
     River birches have rustic and attractive, loose outer bark that profusely peels away in paper-thin strips from trunks and limbs, a reason why this species is planted on many lawns.  This tree also has appealing, drooping catkins that sway a bit in the wind during winter and early spring.
     Ash-leafed maple trees have decorative pairs of seeds on their twigs through winter.  Each seed has an embryo and food stored in the bulging part and a flat wing that spirals the seed on the wind away from parent trees in spring.  Seeds that aren't eaten by rodents and other critters might sprout into new ash-leafed maple seedlings.
     Shag-bark hickory trees have shaggy bark that looks like it will fall off trunks and branches at any time.  Each long strip of loose bark curls out from the tree at both ends, but the middle of each one is still attached to the tree, for a while.  The shaggy appearance of the bark makes shag-bark hickory trees look rustic and attractive in bottomland woods with damp soil.
     Shag-bark hickories produce many hard-shelled nuts in thick, green husks.  Squirrels chew through the husks and nut shells inside to consume the nuts' meat.  Only squirrels have jaws strong enough and teeth sharp enough to ingest hickory nut meat.  
     The lower limbs of pin oaks droop like the wire supports of an umbrella, making that kind of oak decorative in bottomlands.  And some dead and ginger-brown leaves of pin oaks cling decoratively to their twigs through winter.  Sleet rattles through those crisp leaves, adding more natural sound in the quiet of winter.
     Pin oaks also produce lots of small acorns that are food for white-tailed deer, black bears, rodents, wild turkeys, American crows, blue jays and other kinds of birds and mammals.  Squirrels and jays store pin oak acorns in the ground and tree cavities to eat during winter.
     Swamp white oaks are uncommon anywhere, including here in Lancaster County.  This is another rustic, attractive stream-side and bottomland tree.  Swamp white oaks have slightly gnarled limbs, rough bark and some dead leaves clinging to their twigs all winter.  And they produce acorns that lots of wildlife consume.   
     While admiring those floodplain trees along the stream, I saw one abandoned nest each of bald-faced hornets and Baltimore orioles.  Though each of those beautifully-built cradles was created the summer before, they were not visible until winter when deciduous foliage is off the trees.   
     Some bigger trees in those riparian woods each had a few cavities in them, caused either by woodpeckers chipping nurseries from dead wood on limbs or wind tearing branches off trees, exposing the wood underneath to insects and decay.  Carolina chickadees, house wrens and other small, cavity-nesting birds, and gray squirrels, flying squirrels and deer mice raise young in the smaller hollows.  And raccoons, barred owls, wood ducks, American kestrels and other critters live and rear offspring in larger cavities.  
     Many roots of some trees that sprouted right along the waterway were exposed to view because of the stream washing away parts of some banks over the years.  Those sheltering tangles of roots are home to raccoons, mink, nesting Louisiana waterthrushes and wintering winter wrens.  
     Riparian trees are decorative, and feed and shelter wildlife that live among them.  They make bottomland woods more enjoyable to visit, even in winter.