Saturday, November 8, 2014

November by David Holt

The November Watch

As the cold front passed through both of them knew
that northwest winds would be close behind.
They'd hie to a mount, a veritable fount,
of hawks of singular mind.

For south through the skies the hawks would now fly,
seeking land that is more provident.
So the wife and the man would take up a stand,
to witness this marvelous event.

All season they waited, their yearnings unsated,
for weather that just now occurred.
But the weather stayed sober through September and October
and the man and wife were deterred.

But with this happenstance they had one more chance
to view hawks majestic and near.
They both had agreed that all they would need
was a place where the skies would be clear.

They should have known better, but their zeal without fetter
took them up to a place they both knew.
A place they oft went to view this event
but where young skies rarely showed blue.
(They called it Pott's number two)

Now high in the sky what came to their eye?
Not a hawk nor even a cloud.
For the fog settled down, around all around
engulfing them in a gray shroud.

Now the fog rolled and rolled,
borne by winds that were bold
keeping hawks even vultures from sight.
They'd committed their day yet struggled to stay
to witness a marvelous flight.

Not only the shroud (that infinite cloud)
would hamper their efforts that day.
But the air that was cold borne by winds that were bold
caused their bodies to tremble and sway.

What brought us to this? They would now reminisce,
balmy days that were theirs in September.
They'd come face to face with faltering grace,
of the fact that it is now November.

They decided to persist while nature would insist
on their ouster with all of her might.
We've come here this day and, by God, we will stay
to witness a marvelous flight.

By the hour of eleven the sky seemed to leaven,
and for moments the sun did peek through.
Putting them in new light, an astonishing sight,
the sky was still there and still blue.

By twelve the shroud lifted, its vastness was rifted
breathing into their spirits new life.
On hopes that now soared, “We'll get our reward,”
said calmly the man to the wife.

As the hours now passed they kept up the glass
scanning vistas in new winter's form.
But the hawks were not there in that cold northern air.
They wondered if they'd ever be warm.

A Redtail hung high with ground searching eye
'cause by now it needed to prey.
And Ravens flew 'round - those ebony clowns
'Twas all they'd seen there that day.

Defeated and in anguish they dared not now languish
for the sun was sinking down low.
But the air was so clear, forty miles seemed so near,
they slowly made ready to go.

When the car had been loaded and its engine was goaded
 to whisk them briskly away.
“Permit one more scan,” said the wife to the man,
for something to rescue this day.

As she searched in the blue there came into view
a bird of enormous size.
She called out in glee for the man to come see,
she surely had garnered a prize.

From out of the blue on wings straight and true,
came a bird with an aura so regal
They felt not the cold nor the winds that were bold.
They were watching a young Golden Eagle!

It reveled their eyes as it wheeled in the skies
showing wings with patches like snow.
Gold hackles were seen as if it had been
put out there, just for the show.

Now both of them knew they must savor this view
as it soared with such pride, white tail spread so wide.
Too soon it will end and let the cold creep back in.
Even now it had started to glide.

And, breaking the spell they bid sad farewell
to its visage as southward it soared.
“In all of my life,” said the man to the wife,
“There was never a sweeter reward.”

They'll always remember that watch in November,
with a sense of utter delight.
Even nature's harsh way can't tarnish that day.
It was truly a marvelous flight!

David Holt
March 1984

October by David Holt

The October Puzzle

Flap, flap, flap, sail
on stubby wings and a long thin tail
flies a raptor thru the steel gray sky
which we now must try to identify.

The very first traits that meet our eye
puts it in the genus accipterii.
Though our task thus far has been met with ease,
we now must choose one of three species.

The mighty “Gos” we reject out of hand,
as it rarely passes by our stand.
So akin are the two that now remain
they strain our eyes and boggle our brain.

Protruding head and rounded tail,
wing beats of strength, less flap more sail,
all of which when seen without a squawk
should declare the bird a Coopers hawk.

But, if the bird is not so near
as to render these traits pure and clear
We simply deduce right there and then,
that the bird in question is a mere Sharpshin.

But, how can we say with certainty,
of a bird that's just too hard to see
It has traits that make it a Coopers hawk
Or if indeed it is a Sharp-shinned hawk?

When the traits we need cannot be had
'cause they're just too vague when the view is bad
We simply must swallow our birding pride
and call this bird unidentified.

David Holt
November, 1989

Sunday, November 2, 2014

A Tribute

Harvey's Knob
A Tribute

There is a hawkwatcher named Bill
Each fall he climbs a great hill
To seek out a flight 
of raptors that might
in the end give him a big thrill.

There is a hawkwatching host
who spots more raptors than most
when the skies in her view
are less gray and more blue
She is known as Bluesky Joyce.

And Baron too climbs that hill
to see raptors that give him a thrill.
He keeps a good count
of what is seen on that mount
So we all can share in his thrill.

And then there's Barry, what more can be said,
as he brings to us gravy and bread.
He picks the best days 
that don't always pay,
but we are always glad to be fed.

And then there is Carl, KT, Matt, Dillard, and Dave
who fill in for all, to catch every wave
Of raptors they count 
up there on that mount
to see that the record is evermore saved.

Now, where is that mount?
Where we view hawks and count
that marvelous migrating mob.
T'is a ridge that is blue
where they fly straight and true,
O'er a place that's called Harvey's Knob.

Dave Holt

Wednesday, October 1, 2014

A Challenge to Hawkwatchers

How to find migrating hawks in the Southern Appalachians

We all know that migrating hawks achieve their long flights via soaring flight. Soaring flight requires certain meteorological conditions in conjunction with local topography. The two primary sources of soaring flight are the solar induced thermal and ridge crossing winds. The primary means of soaring flight is the solar induced thermal. Solar induced thermals will exist as long as the sun is illuminating the landscape. Ridge crossing winds will only exist when a high pressure system is opposite a low pressure system on opposite sides of the ridge. Therefore thermal soaring is the rule and ridge lift soaring is the exception to the rule.

Solar induced thermals can exist anywhere in the hawkwatchers purview. That purview is limited to three quarters of a mile for a Broad-winged hawk seen by the naked eye. Add an optical enhancement and that purview may be increased to perhaps two miles for a Broadwinged sized hawk. But, the fact remains that a hawkwatcher visiting a so-called hawkwatching site must know that the site is surrounded by terrain that produces solar induced thermals.

That brings us to Harvey's Knob. Harvey's Knob is rife with terrain that produces solar induced thermals prior to the Autumnal Equinox that occurs around September 21 each year. After the Autumnal Equinox the sun does not illuminate the western slopes of the Blue Ridge within the purview of a hawkwatcher at Harvey's Knob. Therefore no thermal soaring hawks. That doesn't mean that the hawkwatcher at Harvey's will not see hawks but it does mean that the hawks will be very hard to find as the solar induced thermal will be out over the Great Valley rather than close to the site.
For spotting thermal soaring hawks after the Autumnal Equinox it is recommended that a hawkwatch be established at the Woodpecker Ridge Nature Center. The Woodpecker Ridge Nature Center is located out in the Great Valley where solar induced thermals will abound after the Autumnal Equinox, bringing the thermal soaring hawks into view.

Ridge lift soaring hawks will still be in view but in converse to Harvey's Knob they will be hard to spot. I have witnessed each of these conditions for counting the most hawks migrating through our area and I am convinced that a hawkwatch should be established at the Woodpecker Ridge Nature Center, especially after the Autumnal Equinox. I cannot convey the joys of hawkwatching at Woodpecker Ridge but I can say that looking down on the back of a Merlin from the platform was an experience embedded in my memory.

Dave Holt

Tuesday, September 16, 2014

September 16th, 2014

Started with an Early Eagle close:

Then it was a bit slow with a few small kettles and individual Broadwings.

Then came the class:

Then came the birds (as if responding to the teacher's voice:

Then the class left and the Eagles came (Green and Gold):

Some more kettles came and went and then Darryl went:

As we all did after a very satisfying day!

Wednesday, September 3, 2014

Thermals - David Holt

A definition is in order.  A solar induced thermal is a column of rising air that is created by the sun and it will henceforth be referred to as simply a thermal.  Thermals are generated by the sun’s heating of the ground in an uneven manner.  As the sun illuminates the earth’s surface, certain areas of that surface are more susceptible to heating than other areas. Therefore certain portions of the ground are superheated when compared to other portions.  The air above those superheated portions of the ground then becomes superheated by conduction.  Now we have a parcel of air that is superheated relative to the surrounding air.

The parcel of superheated air contains molecules that are extremely agitated and vibrate more than those in the cooler surrounding air.  The vibration of the molecules causes them to collide with one another thus knocking them about to the extent that the superheated parcel of air is less dense than the surrounding air.  The less dense parcel of superheated air now begins to rise.  Thus the thermal is born.
It must be stressed that it is the ground that is superheated first and the air above the superheated ground that is superheated second.  The sun cannot superheat parcels of air as the air is uniform in color and texture while the ground isn’t.  In fact the air is transparent to the suns rays.  Therefore the ground with its variations in color, texture, and moisture content is of prime importance in the generation of a thermal.  Just consider that the ground is heated first and the air above it second.
To illustrate the variations in color and texture consider the following.  A freshly plowed area surrounded by fields of dried grasses.  The plowed area is darker than the dried grasses thus allowing it to absorb heat rather than reflect it.  The plowed area will become superheated.  A strip mall with an asphalt parking lot situated in the median of a concrete highway will become superheated due to the dark asphalt absorbing heat while the light concrete roadway reflects heat.  A grassy knoll surrounded by grassy fields will become superheated quicker than the area around it even though the surrounding area is of similar color and texture.  This would be because the knoll has better drainage and will shed moisture quicker than the low-lying ground.  Heavy moisture in the ground will delay the superheating of the ground as it becomes a heat sink.

When that first superheated parcel of air begins to rise, it is replaced by the surrounding cooler air which in turn becomes superheated and it in turn starts to rise.
 Soon you have a column of air rising and it will continue to rise, cooling as it rises until it cools to the temperature of the surrounding air at some altitude above sea level. That altitude will depend upon the vertical stability of the air and the humidity of the air in the thermal.  Also the detection of a thermal will depend upon the relative humidity at the earth’s surface.  If the air is sufficiently humid then a cloud will form capping the thermal when the dew point temperature of the rising air reaches the dew point temperature of the surrounding air.

This cycle of superheating, rising air, and cooling of the air will continue as long as the sun is shining.  But, anyone who has spent some time hawkwatching has noted that by one o’clock PM on a hot and humid day the cumulus clouds spawned by the thermals have begun to amass and at some point amass sufficiently to block the sun from striking the ground.  And, you guessed it, the thermals will stop forming.  This cessation of the thermals can cause a decrease in the number of hawks counted, as they may not find a thermal to soar upon within the purview of the observers at the hawkwatch.

Not to worry, as the thermals may reappear as the clouds caused by the early morning thermals begin to spread and in some cases dissipate allowing the sun to once again illuminate the ground.  If this is the case the cycle will repeat itself albeit in different places until nightfall.  The foregoing has described a model of the birth, life, and death of a solar induced thermal.  But there are some wrinkles to this model that should be addressed for the hawkwatcher stationed in the Blue Ridge Mountains of southwest Virginia.

In September the mountains in southwest Virginia are covered with the rich foliage of deciduous and coniferous forests.
  Stand at your site and look around and you will see a sea of uniform green some fifty to a hundred feet above the ground all around your site.  How is the sun ever going to illuminate the ground unevenly through this canopy of green?  To my knowledge the sun cannot possibly provide a rich source of thermals along the mountainous territory of southwest Virginia and yet many hawks are counted in this venue.  And, during that same time the thermals are the rule while all other soaring means are the exception to the rule.

In the vicinity of Harvey’s Knob there is a black asphalt strip in the middle of that sea of green.  There is an occasional outcrop of rock and a mowed area that resembles a clear cut. The parking lot at Harvey’s Knob is a non-uniformity in color that provides a source for a thermal.  How many hawks have you counted directly overhead in the Broad-winged hawk season?  Those of you who are reading this from other lookouts make the same survey.  Remember all you have to consider is a circle with a two to three mile radius centered on the site.  That will indicate possible thermal sources within your purview thus providing a reason for your counts on those days when the winds are light and variable.

And there are other questions regarding the anatomy of a thermal that I will be glad to field.  But, remember that I am not a meteorologist.  I am merely a hawkwatcher who has concentrated his efforts into understanding why that hawk was in view when I went to some hawkwatching site.  This wasn’t meant to be a scientific paper as it wouldn’t pass muster in scientific circles.  It is a paraphrase of the science of a thermal as I have understood it from the various sources I have researched.  If I have left something out I am sorry, but I do think I have provided something for you to think about during those long hours when no hawks are in sight.  I submit my Email address for anyone who wishes to keep his queries private.
Dave Holt 12/20/06

Miscellany (of years)

"Why I love Vultures" by TED
Do Hockey and Birding MIX?
Vulture Self ID!

How do birds survive huge storms - NYT?

The future of hawk counting, Perhaps?

   And, as it gets late, the Red Tails turn their headlights on:

Name this bird:

  Great story and a great video about an old Bald

RedTail on DESIGN?

Political BIRDS?

Which coffee is best for the BIRDS?

When is Green not GREEN!


What you need to know about binoculars (from Cornell Lab) is
here to SEE!


 Eagle #1 2011 (8/15)

Eagle #90 2011 (10/21)

Eagle #89 (with harness?):

Big Bird:

(Click to read)


Pictorial Summation of the 2011 Broadwing Year:


Osprey Recovery HERE


This place is incredible:
of Virginia

Golden Eagle story from 

A Boy and His Dog:

See What A Mountain Will Do:

Sandy at Buchanan:

Sandy at Montvale: