Saturday, July 23, 2016

Wood Thrushes

On our hikes around Sandy Lake, in northeastern Ohio, this week, I have encountered the usual mix of permanent and summer residents.  Of note has been a fair number of wood thrushes, more common than I would have expected in the limited, lakeside forest.

Indeed, a steady decline of wood thrush populations has been documented over the past half Century, perhaps due to fragmentation of forests by agricultural and suburban development.  Though still fairly common in the eastern U.S. and southeastern Canada, these eloquent songsters are known to be common targets of brown-headed cowbirds, which parasitize their nests; forest fragmentation likely increases their exposure to the cowbirds as well as to avian predators.  Wood thrushes typically place their nests in saplings and shrubs of the understory and may produce two broods during the spring-summer season.

Feasting on a wide variety of ground-dwelling invertebrates and an assortment of berries, these reclusive summer residents may be mistaken for immature robins by the casual naturalist.  Like their red-breasted cousins, they sing early and late in the day but their tune, often characterized by self-harmony, is far more impressive.  Before autumn chill envelops their breeding ground, wood thrushes head for Central America to winter in tropical forests.

Wednesday, July 20, 2016

Back at Sandy Lake

Attending my wife's family reunion in northeast Ohio this week, we have returned to Sandy Lake, southeast of Kent.  Their cottage sits on the north shore of that scenic kettle lake, offering a broad view of the open waters.

Fortunately, the recent Midwest heat wave has not yet enveloped this corner of the Buckeye State; the air is relatively dry and afternoon highs have been in the low-mid eighties (F).  For a birder such as myself, the lake is always interesting; man-made nest houses attract clouds of purple martins while a pair of ospreys nest nearby and fish on the lake for much of the day.  A lone bald eagle and several red-tail hawks have also been visiting and double-crested cormorants often stop by to dive for their meals.  Other common residents include killdeer, Canada geese and a host of riparian songbirds; among the latter, eastern wood pewees, cedar waxwings and eastern phoebes flycatch from the shoreline trees.

As in the past, I intend to explore the lake from a kayak during our visit, getting a close look at the amphibians and aquatic reptiles that share this pleasant retreat.  Besides, an occasional peaceful escape from the reunion activities will make the entire experience more enjoyable!

Monday, July 18, 2016

Climate of the British Isles

Like many Americans, I watched parts of the British Open over the weekend and, for those of us caught in hot, humid weather, the cool air in Scotland looked very inviting.  While we sat in our air-conditioned homes, perhaps in front of a fan or two, the players and gallery members were festooned in fleece jackets and windbreakers.

Indeed, mid-summer highs in Scotland, Wales, Ireland and western England are generally in the low-mid sixties (F).  Prevailing winds are from the southwest, bringing cool, moist air in from the Atlantic; headlands along the coast and highlands throughout the interior force the air to rise, inducing upslope mist and precipitation.  Though the United Kingdom stretches across latitudes comparable to southern and central Canada, the Gulf Stream provides a steady supply of relatively warm air and winter, afternoon highs are generally in the forties (F) across the lowlands west of the mountains.  On the other hand, atmospheric troughs, dipping across the Northern Atlantic, bring copious rainfall to the region; western lowlands receive about 60 inches each year while mountainous areas receive 120 inches or more.

East of the central highlands, the climate is more Continental.  While the classic image of London includes fog and drizzle, that city receives less annual precipitation (about 27 inches) than most urban areas in the central and eastern U.S. (generally 35 inches or more).  Heat waves may result from stagnant weather patterns across Western Europe and frigid air may pour southward from the North Sea as polar fronts invade Scandinavia and Eastern Europe; as a result, seasonal temperature variations are much greater across eastern England than in regions along the Atlantic Ocean, which moderates the effects of cold and warm fronts.

Sunday, July 17, 2016

The Delusion of Purpose

In the course of human tragedies, whether they are caused by an accident, illness, natural catastrophe or criminal activity, we often hear the retort that "everything happens for a reason."  The implication is that God has a master plan into which the tragedy fit; of course, it also implies that there is a sadistic, manipulative deity who established and carries out such a plan.

For many of us, it is more plausible that tragedies are an unfortunate part of life, that nature is not fair and that humans are capable of evil behavior.  Believing that tragic events are part of a grand scheme may serve to lessen the grief of survivors but mysticism has nothing to do with truth; indeed, this belief places a significant psychological burden on those affected by tragedy, leaving them to wonder what achievements are expected in response.

Life is fragile and death is often random.  While efforts to stay healthy and avoid injury may reduce the risk of an early death, tragic events occur nonetheless.  Falling victim to such tragedies is often a matter of pure bad luck; to suggest otherwise is to disrespect the lives of those who were lost.

Saturday, July 16, 2016

Summer Vagrants

When it comes to finding avian vagrants (species found outside their usual range), fall and winter are perhaps the best seasons for birders; many species wander widely as they head for wintering grounds and a variety of irruptive species grace Temperate latitudes during the colder months.  In addition, waterfowl, loons, grebes and other aquatic birds move in concert with open water sources and food availability, sometimes veering far off-course (or off-schedule) from their usual migration patterns.  By contrast, spring migration and activity, driven by the chemistry of procreation, tends to be more direct and predictable.

In summer, once the breeding season has ended (or even beforehand in the case of juveniles), southern species often wander north of their usual range, seemingly enjoying a bit of adventure while the weather is warm and food is plentiful.  Mexican songbirds often turn up in the American Desert Southwest during the summer months and southern waders (such as roseate spoonbills, little blue herons and white ibis) may wander up the coasts or along major rivers; their appearance in the Heartland or New England is a special treat for avid birders.

Late summer is a good time to observe these summer vagrants, now joined by the first waves of migrant shorebirds that have left their Arctic breeding grounds.  While oppressive heat still lies ahead, these travelers offer an early sign that the glorious days of autumn are just around the proverbial corner.

Thursday, July 14, 2016

A Soggy Floodplain

After several days of intermittent, heavy rain, a soggy landscape greeted me at Eagle Bluffs Conservation Area this morning; flooded fields, swollen sloughs and bank-full pools seemed to affect a variety of species.  Powerlines were loaded down with mourning doves, dragonflies swarmed above the drenched croplands, cricket frogs called from the transient shallows and cottontails lounged on the roadways, perhaps driven from their burrows by the flooding.

While few mudflats remained above water, they attracted some of the first "autumn migrants," including greater yellowlegs and solitary sandpipers.  Great blue herons were common but less abundant due to the higher pools; they were joined by nine great egrets and a lone green heron.  Other sightings included bald eagles, double-crested cormorants, belted kingfishers, wood ducks and the usual mix of summer songbirds; four terns (likely Forster's) were observed but were too distant to identify.  As summer advances toward autumn, mourning doves, red-winged blackbirds, common grackles and European starlings are beginning to forage in large (if not massive) flocks.

The wet floodplain, a bit unusual for mid summer, will likely dry out over the coming week as heat and sunshine return to the Heartland.  Expanding mudflats will soon welcome a tide of migrant shorebirds and shallow pools may entice southern waders up the Missouri Valley.  Whatever the fickle weather systems bring, we have passed the summer doldrums at Eagle Bluffs and migration season, however tentative, is now underway.

Wednesday, July 13, 2016

The Savannah River

The upper tributaries of the Savannah River rise on the eastern flank of the Blue Ridge Mountains in southern North Carolina.  The Tallulah River rises southwest of Franklin, flowing south and then southeast while the Chattooga River (designated a Wild & Scenic River) rises near Cashiers, flowing southwestward to form the northernmost section of the Georgia-South Carolina border.  Just below the Tallulah River Gorge, these two rivers join in Lake Tugalo, which is drained by the Tugaloo River, another segment of the Georgia-SC border.  Within Lake Hartwell, the Tugaloo merges with the Seneca River (flowing down through northwestern South Carolina) to become the Savannah River.

Flowing southeastward, the Savannah soon enters Thurmond Lake, a massive, branching reservoir along the Georgia-SC line.  Below that lake, it crosses the Fall Line at Augusta, Georgia, dropping from the hard, crystalline bedrock of the Piedmont to the soft sediments of the Coastal Plain.  From this geologic border, the Savannah River continues southeastward to its estuary along the Atlantic Coast, just north of Savannah, Georgia.

Having originated as a web of whitewater streams in the montane forests of the Blue Ridge, the lower portion of the Savannah meanders through a flat landscape of pine woods, wetlands and bottomland hardwoods; of course, agricultural and wood product industries have significantly altered these natural ecosystems.  Fortunately, the Savannah River National Wildlife Refuge, near Savannah, was established to protect and restore these habitats, home to alligators, ospreys, bald eagles, swallow-tailed kites and many other species of wildlife.  Unfortunately, according to the EPA, the Savannah River remains one of the most polluted rivers in the U.S., ranking third in the amount of toxic chemical discharge that it receives.

Tuesday, July 12, 2016

Rainout at Eagle Bluffs

When I arrived at Eagle Bluffs Conservation Area this morning, a gray overcast stretched above the Missouri River floodplain and the air was pleasantly mild.  A flock of blue grosbeaks fed along the entry road and, farther along, a small bevy of bobwhites darted across my path.  Mourning doves, indigo buntings, dickcissels and red-winged blackbirds were abundant in the roadside fields and I anticipated a very productive morning at the refuge.

Then, halfway into the preserve, I turned eastward and was treated to a spectacular but threatening view to the north.  A massive shelf cloud stretched across the Missouri Valley and the riverside hills were rapidly disappearing behind the gathering gloom.  Within fifteen minutes, I was enveloped in the storm with its frequent lightning and torrential rain.

Faced with other commitments later in the morning, I accepted nature's not-so-subtle hint and left the refuge, catching glimpses of stoic, rain-soaked herons along the way.  I'll be back later in the week.

Monday, July 11, 2016

The Madden-Julian Oscillation

First described in 1971, the Madden-Julian Oscillation (MJO) is an area of atmospheric disturbance in the Tropics, characterized by a dipole of suppressed and enhanced convection (precipitation) that propagates eastward throughout the year; depending on its forward velocity, this "wave" circles the globe every 30 to 60 days.  Like other oceanic oscillations, its intensity varies from year to year.

Interacting with other atmospheric disturbances, this Oscillation affects monsoon patterns and the development of tropical storms; depending on its position at any given time, the MJO may fuel or suppress tropical storm activity (see Tropical Storm Dynamics).  Acting in concert with atmospheric troughs and ridges to its north, the Oscillation may also feed bands of heavy precipitation (such as the Pineapple Express).

The current outbreak of hurricanes in the Eastern Pacific is thought to reflect interaction between the El Nino and Madden-Julian Oscillations.  Relatively quiescent early in the summer, the East-Pac Hurricane Season has become especially active in recent weeks.

Sunday, July 10, 2016

Pileated Woodpeckers in Farm Country

After a week in Cincinnati, I left for Missouri this morning, driving northwest through Indiana.  Despite the sunny, mild weather, only a dozen or so birds flew across my path between Cincinnati and Terre Haute; a great egret and a yellow-billed cuckoo were among them but almost half were pileated woodpeckers.

Fairly common in forested areas of the Eastern U.S., Canada and coastal regions of the Pacific Northwest, these large woodpeckers may be mistaken for crows at a distance; up close, however, their striking red crests, white facial stripes and large white underwing patches make identification easy.  Favoring mature forests and wooded swamplands, pileated woodpeckers are monogamous; as breeding season approaches, they excavate large oval or rectangular cavities in dead trees.  Feeding primarily on carpenter ants, they also consume a wide variety of beetles, nuts and berries; three to five young are generally raised in a single brood each year.  Vacated cavities are later used by screech owls, tree squirrels, martens, bats and a host of cavity-nesting songbirds.

Once threatened by the clearing of forests across the Eastern U.S., pileated woodpeckers have since adapted to a wide range of woodlands and may even be found in suburban parks; indeed, some turn up at backyard feeding stations during the colder months.  This morning's encounters attest to their presence in Midwestern farmlands, where woodlands are primarily limited to hillsides and stream channels.

Wednesday, July 6, 2016

The Nature of Derechos

Derechos are long-lived wind events that begin as a cluster of thunderstorms.  When such clusters develop in a favorable wind environment (where surface and upper level winds are moving in the same direction), they often develop a "bow echo" formation, with its leading edge pointing in the direction of these steering winds.

Downbursts within the thunderstorms produce gust fronts of chilled air that move ahead of the bow echo; ominous shelf clouds commonly reflect the presence of these gust fronts.  Lifting the warm, humid air into which they move, the gust fronts fuel another line of thunderstorms, propagating the bow-shaped cluster as the system moves forward.  Rapid movement of the thunderstorms, combined with the high speed of the gust front winds can produce destructive straight line winds (often exceeding 75 mph) across the leading edge of the bow echo.

By definition, a derecho occurs when the above dynamics persist along a swath of 250 miles or more and produce wind gusts of at least 58 mph.  As we have seen this summer, derechos often develop along the northern and northeast rim of a high pressure ridge, where an unstable atmosphere ignites the thunderstorms and strong winds both generate and steer the bow echo formation.

Tuesday, July 5, 2016

Juno & The Ark

Today, the Juno probe began to orbit Jupiter.  After traveling 1.8 billion miles over five years, the probe will spend the next two years studying our solar system's largest planet, beaming information back to Earth, some 500 million miles away.  Following that mission, Juno will crash into the massive planet, the first product of human ingenuity to reach its surface.

Meanwhile, two days from now, The Ark will open to the public in Williamstown, Kentucky.  Built to specifications outlined in the Bible, the Ark will house exhibits which "reveal" specifics regarding the life of Noah, the Great Flood and the management of the menagerie onboard the wooden ship.  True believers will no doubt flock to the site, paying good money to reinforce their faith.

This week's events highlight the ongoing juxtaposition of scientific achievement and religious mysticism in modern human society.  Long before humans understood the nature of our solar system, the story of Noah and his Ark were ingrained in Judeo-Christian culture.  Despite the knowledge that we humans have since attained, the simplistic concept of a Great Flood, documented in Holy Scripture, carries more weight among believers than does the vast amount of scientific evidence that validates the theory of evolution.

Sunday, July 3, 2016

Algal Sludge in Southeast Florida

Over the past few weeks, a thick layer of putrid algae has been accumulating along canals and estuaries in Southeast Florida, centered near Stuart.  This unnatural scourge is threatening both the local economy and the welfare of regional wildlife.

The culprit is polluted water in Lake Okeechobee which, during periods of heavy rain, is released into the upper watersheds of adjacent rivers to relieve pressure an an aging dike; the St. Lucie and Caloosahatchee rivers receive the brunt of the runoff.  Once the nutrient-rich freshwater mixes with sea water at the coast, an algal bloom is triggered, covering the shallows with a toxic carpet of noxious and unhealthy sludge.  The only remedy is to cut off the flow of nitrogenous waste (primarily agricultural fertilizer) that fuels the bloom.

Repeated episodes have occurred over the years and politicians, at both the State and Federal levels, have stymied efforts to provide a solution (i.e. cleaning up Lake Okeechobee and expanding its basin to eliminate seasonal overflow).  While the tragic effects of pollution are clearly evident in this case, much of human-induced pollution across the globe goes unnoticed for extended periods of time, destroying ecosystems and poisoning wildlife long before the effects become evident.  The warnings of conservationists are often ridiculed by polluting industries (and the politicians whom they fund) until species are lost, fisheries are decimated and our natural environment is forever changed.

Saturday, July 2, 2016

North of the Dome

Over the past week, a subtropical dome of high pressure has been developing across eastern Mexico and the northern Gulf Coast.  Pushing into the Southern Plains and Lower Mississippi Valley, it is both shunting Pacific storm systems to the north and fueling the Southwest Monsoon.

Along the outer edge of this atmospheric dome, moisture flows across Mexico (from east to west) and then up through the Four Corner States; this flow is augmented by low pressure over the Desert Southwest, which draws in moisture from the Sea of Cortez.  Just north of the dome, the moisture combines with inflow from the Pacific and moves eastward along a stationary front; pulses of low pressure move along the front, igniting thunderstorms and torrential rain.  "Training" across the same path (from eastern Kansas to southern Ohio), the storms will drop up to 5 inches of rain in some areas; northern Missouri is forecast to receive the brunt of the deluge.

Here in Columbia, light drizzle developed at 6:30 AM; steady rain has since moved in and will likely continue (off and on) for the next two days.  While the rains will provide welcome relief from our ongoing drought, heavy downpours on sun-baked soil will rapidly drain into creeks and rivers, setting the stage for flash floods.

Friday, July 1, 2016

In Search of Grosbeaks

Having learned that blue grosbeaks were recently sighted at Eagle Bluffs Conservation Area, a friend and I searched for them on our morning visit to that fabulous floodplain refuge.  As is often the case in nature, we failed to locate our quarry but saw many other species in the process; indeed, we encountered more than 45 avian species during our two hour visit.

Among the morning highlights was a large flock of American white pelicans, an abundance of great blue herons, a few bald eagles, a handful of great egrets and the usual mix of summer songbirds, dominated by indigo buntings, dickcissels, tree swallows and, of course, red-winged blackbirds; other sightings included yellow-billed cuckoos, eastern phoebes, eastern kingbirds, Baltimore and orchard orioles and a lone blue-gray gnatcatcher.

Fortunately, blue grosbeaks often stick around to raise a second brood and we should have more opportunities to observe these attractive summer residents before they depart for Central America and the Caribbean.  Whether those attempts will be fruitful remains to be seen but uncertainty fuels the joy of birding.

Thursday, June 30, 2016

Wild Grape Vines

Today I engaged in my semiannual attempt to control wild grape vines throughout the wood border of our Columbia, Missouri, property.  While the fruit of this fast growing vine is an important food source for many songbirds and mammals, the aggressive vines can cause significant damage to trees and shrubs, blocking sunlight and weighing down the supporting plants.

Native to humid, Temperate areas of the Northern Hemisphere, wild grape vines are represented by at least 60 species; of course, domesticated grape vines are derived from these wild species.  Most wild grape vines (unlike domesticated species) produce only male or female flowers on any given plant; these flowers, which appear during the second year of new growth, are pollinated by the wind and yield loose clumps of purple-black grapes by late summer.  Seeds are dispersed by wildlife that feast on the fruit but new growth may also sprout from older vine stumps (as many homeowners know all too well).  Frequent cutting of the vines is the most ecologic means of controlling their expansion.

When I was a pre-teen in the woods of Greater Cincinnati (see Wonderland), large grape vines were a godsend, allowing us to swing out over ponds or creek beds.  As an adult homeowner, my image of these prolific plants has become far less positive.

Tuesday, June 28, 2016

Symphony at Dusk

Drier air, a gentle breeze and cooler temperatures drew me outside this evening for a late-day survey of our property.  Since the trees are in full leaf and the daylight was fading, there was far more to hear than to see.

A rising background din was provided by annual cicadas that started their tune-ups earlier this week; crickets joined in as well, their chirps not near as intense as they will soon become.  As usual, the songs of robins and cardinals dominated the avian chorus, mellowed by the soft calls of mourning doves and the distant chatter of chickadees; not to be ignored, Carolina wrens delivered their loud, ringing tunes from hidden retreats.  Squadrons of chimney swifts twittered overhead and the sharp "peents" of nighthawks echoed from the darkening sky.  Some nights, though not this evening, the questioning call of a barred owl rises from the nearby woods, bringing dusk's symphony to a close.

To fully appreciate the diversity of our wild neighbors, we must come to know them by voice as well as by sight.  A pleasant summer evening offers a good opportunity to practice that skill.

Monday, June 27, 2016

The Rise of Nationalism

As evidenced by the Brexit vote in England and the success (hopefully transient) of Donald Trump's Candidacy, nationalism is on the rise across the globe, especially in developed Western countries.  This movement seems to have its roots in the inequalities of globalization and the fear of immigration (especially in light of recent terrorist attacks).  Of course, racism and religious zealotry are at play as well.

Unfortunately, some politicians are taking advantage of the anger, fear and intolerance, placing emphasis on the risks of globalization and promising to protect legal citizens from the dangers of immigration, trade agreements and "cultural dilution."  Older, less educated and more provincial individuals, many having lost their jobs to outsourcing and failing industries (e.g. coal mining, manufacturing, textiles), are most receptive to their message.

While some of these inequities and concerns are legitimate, globalization is here to stay and international cooperation is vital in our efforts to assist developing countries, to prevent war and to combat the threats of pollution, ecologic degradation and climate change.  In the end, we must address the problems associated with globalization without resorting to nationalism; otherwise, we will destroy both our economy and our planet.

Sunday, June 26, 2016

Fish Crow at Eagle Bluffs

While surveying a large pool at Eagle Bluffs Conservation Area this morning, I heard a familiar call that echoed from over my left shoulder.  Turning to locate its source, I saw a crow flying across an open marsh, being chased by a trio of red-winged blackbirds.

The crow's call reminded me of lazy afternoons on the seawall at Longboat Key, Florida.  Indeed, this was a fish crow, more often associated with southern coasts but now increasingly common along the larger rivers of the eastern and central U.S.  Like their widespread cousin, the American crow, fish crows are omnivores, feeding on waste grain, berries, seeds, insects, bird eggs, stranded fish, small lizards, small mammals, carrion and human food waste; in fact, they are among the most relentless predators of eggs and nestlings at heronries and sea bird rookeries.

Distinguished from American crows by their slightly smaller size and distinctive, higher-pitched "nasal" call (contrasting with the harsh, raucous voice of their widespread cousins), fish crows generally gather in large flocks and move toward coastal estuaries during the colder months.  Until then, I and my birding colleagues along the Missouri River will lend an ear to their presence and enjoy a bit of audio from the coast in the American Heartland.

Friday, June 24, 2016

Flooding in Appalachia

Yesterday afternoon and evening, a line of strong thunderstorms stretched across the Appalachians, from the Ohio River Valley to south-central Virginia.  Aligned along a stationary front and steered by the jet stream, the storms "trained" over the same areas, unleashing torrential rain (up to 9 inches in some locations).

Falling on the dissected terrain of the Appalachian Plateau and the Ridge and Valley topography west of the Blue Ridge, the copious precipitation drained rapidly from the steep ridges to the primary river valleys; mudslides and valley floods were the result, most severe in southeastern West Virginia and adjacent sections of Virginia.  Unfortunately, most Appalachian towns lie within the valleys and widespread damage has been reported.

Flash flooding is especially dangerous in mountainous terrain since it develops rapidly and escape routes are often limited.  Those living in or visiting such regions are thus advised to heed weather forecasts and take note of potential routes to higher ground; multiple routes should be considered since some roads may be closed due to high water or mudslides.  Beautiful as it may be in sunny weather, mountainous terrain poses unique risks when thunderstorms approach, even when heavy rains fall far upstream.

Thursday, June 23, 2016

Chat Alley

At South Platte Park, in southwest Metro Denver, a trail meanders along a low ridge on the west side of Eaglewatch Lake.  Winding through a landscape of shrubby meadows, lakeside woodlands and groves of cottonwoods, this trail is one of the better avenues for observing woodland songbirds in the south Metro Area.

During the warmer months, yellow-breasted chats are especially common here, delivering their endless sermons from woodland pulpits, their colorful vestments glowing in the bright morning sun; I observed seven of them today, spaced along the ridge.  Other common summer residents include gray catbirds, broad-tailed hummingbirds, yellow warblers, Bullock's orioles, western pewees and house wrens; among the permanent residents are great horned owls, Cooper's hawks, northern flickers, cedar waxwings and black-capped chickadees and this lakeside ridge is a magnet for migrant warblers, vireos and other songbirds (e.g. western tanagers) that stop to rest and feed on their way to the mountains.

In addition, the "chat alley" trail offers broad views of Eaglewatch Lake, which attracts double-crested cormorants, American white pelicans, ospreys, bald eagles, western grebes and a wide variety of waterfowl in the course of the year.  The chats may steal the show on summer mornings but this lakeside ridge has much to offer in any season; the trail is best accessed from parking areas near C-470, via the southern Park entrance from Platte Canyon Road.

Wednesday, June 22, 2016

An Incessant Songster

Working on our Littleton farm this morning, I was serenaded by the calls and songs of many avian residents and visitors.  Dominating this background noise was the incessant song of a male lesser goldfinch, delivered from prominent perches throughout the property.

Arriving along the Colorado Front Range in late April or May, lesser goldfinches initially maintain their gregarious habits, roaming about to feed in weedy fields, across foothill shrublands or on the sunny slopes of lower canyons.  By late June, males begin to establish their territories, announcing that intent with long soliloquies of high pitched notes and whistles designed to attract a mate and keep other suitors at bay.

Like other species of goldfinches, lessers nest in mid-late summer, when the seeds of thistle and sunflowers are most abundant.  Once the young are fledged, these small, attractive songbirds congregate in large flocks once again, heading for the Desert Southwest, South Texas or Mexico before chilly autumn winds rake the Front Range.