Mar 302014
 

I saw a marvelous image posted on Facebook the other day — a  Venn diagram composed of two overlapping circles, one labeled “Science” and the other one “Art”.  The intersection region of the two was labeled “Wonder”.  Today’s offering from the Examiner archives is a pair of articles about the great blue heron, one from a scientific viewpoint and the other from an artistic one.  Both pieces were originally published on June 15, 2010.  The left-hand photograph was taken at Sweetwater Creek State Park, Georgia.  The right-hand one was taken in White House Beach, a mobile home community on Indian River Bay in Delaware, where my dad was living at the time.  He loved watching sunrises and birds from his deck looking out over the open water, I have always share his delight in exploring nature, a trait he encouraged in me from my earliest memories.  Gordon F. Blizard, Jr. passed away in December of 2011; this selection from the archives is dedicated to him. 

 

1-Sweetwater Creek 078

1-Delaware 053

 

 

 

 

 

 

 

 

 

THE GREAT BLUE HERON AS DINOSAUR

From as far back as this writer can recall into his childhood, he has always been entranced by great blue herons.  This fascination is due partly, no doubt, to the fact that the great blue heron (Ardea herodias) is an immense bird, standing nearly four feet tall, and with a wingspan of about six feet.  As such, it would dwarf all of the songbirds he might see at the backyard feeder though the kitchen window of his Pennsylvania home.  But down the street from his home there were ponds and a creek, and from time to time he would glimpse a great blue heron there.  It was nearly always in flight over the treetops or along the stream, body long and streamlined, legs tucked behind, wings flapping loudly.  Once or twice, it even uttered a call sounding like “FRAWNK”, in a harsh and gutteral voice that seemed to emerge from evolutionary prehistory.   For reasons he did not have the words to capture then, but will venture to do so now, the great blue heron has always seemed to belong to the time of the dinosaurs.

One explanation for this image of great blue heron as dinosaur is that, in fact, birds are descended from dinosaurs.  The split appears to have taken place about 160 million years ago, when small, two-legged dinosaurs like Velociraptor began to develop feathers.  Oddly enough, paleontologists have identified feathered, ground-dwelling dinosaurs, indicating that feathers likely evolved from modified scales before they could be used for flight, perhaps as a means of regulating body temperature or displaying during courtship. The oldest bird fossil is that of Archaeopterix, dating back about 155 million years, an odd mix of avian and reptilian attributes.  This early bird may have gotten the worm, but it did so using a mouth containing teeth.  It also possessed three separately-clawed fingers and a bony tail.  Like later birds, however, Archaeopterix had wings, fused clavicles, and feathers.

So in a sense, perhaps our recognition of great blue herons as being like dinosaurs is an instinctive recognition of their actual kinship.  Surely, then, great blue herons must be among the most primitive birds alive today, and therefore closest in relation to dinosaurs?  Amazingly enough, scientists doing protein sequencing analysis have concluded that the closest living relative of the dinosaurs, and therefore our closest point of contact with the Mesozoic, is actually a chicken!    “Kentucky Fried Dinosaur” jokes aside, then, why does the chicken fail to evoke more than vague thoughts of farm life and possibly soup, while the majestic heron transports this author to the geologic past?

The answer lies, quite possibly, in the great blue heron’s resemblance to a pterosaur.  Pterosaurs were an order of reptiles separate from the dinosaurs, which lived throughout the mid to late Mesozoic era (from 220 to 65 million years ago).  The first reptiles to take to the air, pterosaurs had hollow bones like birds, and both soared and actively flew on immense membranous wings.   Images of a pterodactyl in flight do resemble flying great blue herons.  Since pterosaurs evolved about 80 million years before birds split off from the dinosaurs, however, herons and pterosaurs are only distantly related.  So the mystery behind the similarity of appearance has to do with the process of convergent evolution, in which two unrelated organisms both evolve similar body forms and structures in order to meet similar environmental requirements.  Both have large wingspans and streamlined bodies because those attributes are beneficial for flight.

On the ground, though, any resemblance between pterosaurs and great blue herons quickly vanishes.  Tracks of pterosaurs reveal that they were actually quadrupeds, walking on both their hind feet and their wings in a somewhat ungainly manner, possibly as depicted here.  While standing in a stream or along the edge of a pond or bay, however, a great blue heron evokes quite different feelings and images for this writer, ones that tend less toward prehistory and more toward poetry.  They will be the topic of another article on herons, soon to be written.

 

THE GREAT BLUE HERON AS POETRY

The great blue heron stands,

Waiting at the water’s edge;

Avian haiku.

There is something about a great blue heron, poised motionless in the shallow waters of a pond, river, or bay, that is profoundly poetic.  It gazes outward, waiting for the slightest ripple to betray the presence of a fish.  It stands silent, almost blending into the landscape, its long body connecting water and sky.  In particular, it evokes haiku, the lean and elemental seventeen syllables of Japanese verse that contains at once both a single instant and the entire universe. Not surprisingly, there is even an online haiku publication called The Heron’s Nest.

The great blue heron’s pose while waiting for a meal has much to teach Westerners.  It embodies patience and being in the present moment, waiting for an opportunity to arise rather than trying to make it happen.  Just as it awaits the silvery flash of a fish in the shallows, so the poet sits, waiting for words to form themselves into a poem to surface in her consciousness.

The great blue heron also embodies silence and solitude, standing alone against the elements, aloof in the shallows.  It may stand in one place for hours, as the sun makes its way across the sky and sets in the west.  Approach too closely and it will abruptly take off with a flapping of wings, searching for a place to fish without disruption, further down the coast of the bay or up the river.

The great blue heron is not always a bird of stillness, though.  Indeed, despite the haiku publication title, the heron’s nest can be quite a raucus place.  Herons build their nests of sticks lined with reeds, mosses, and grasses high in the trees in wet, forested areas.  They nest in dense colonies called rookeries, which can be both smelly (from the abundant bird droppings) and loud (from many squawking birds).  As herons return to a rookery year after year, eventually their tree stand is killed off, forcing the birds outward, leaving a bulls-eye pattern with a central core of dead trees and an outer ring of nest trees that are slowly dying.   In these nest areas, great blue herons take on a nearly opposite personality to that of the quiet fishers that they appear to be at other times in the year.  At the rookeries, herons are loud, argumentative, and destructive.  But perhaps the aspects of great blue heron behavior encountered in a rookery might be viewed as a necessity.  Maybe their nesting behavior is required in order to balance out their other, more poetic, solitary and silent selves.

Dec 302013
 
Barbed wire emerges from tree stump, Little Mulberry Park.  26 Dec. 2013

Barbed wire emerges from tree stump, Little Mulberry Park. 26 Dec. 2013

Mid 20th Century stacked rock piles, Madison County, North Carolina.  From Early Georgia article by Thomas Gresham (1990).

Mid 20th Century stacked rock piles, Madison County, North Carolina. From Early Georgia article by Thomas Gresham (1990).

What do the stone piles of Little Mulberry Park in Gwinnett County have to tell us about the past history of the area?  If they are not prehistoric burial and ritual sites, what other possibilities remain?  In this final blog post in my series about this stone mounds, I will explore another explanation for their origin, one that relates them to the past agricultural history of the area.  Evidence that the land was once open pasture can be found in the large pasture trees that follow former fence lines (see my post from 12/28 for an example), and bits of barbed wire that emerge from old tree stumps in the park.

But why would settlers choose to pile up rocks on the property in the first place?  Patrick Garrow, the archaeologist who did the initial investigation of the site in 1988, argued that the stone piles locations and structure argued against the stones having been piled up by farmers clearing the ground for planting.  Indeed, since the land was never tilled but only used for pasture, that explanation seems unlikely.  Perhaps the farmers wanted to clear the ground so that there would be more graze for their animals, or so that the animals would be less likely to injure themselves?  Why, then, go to the trouble of stacking the rocks?

It is the fact that the rocks were stacked which convinces many people that the mounds are evidence of a prehistoric origin.  Clearly, someone (or someones, plural) went to considerable effort to place the rocks in layers that can still be seen today.  In fact, as archaeologist Thomas Gresham argued in an Early Georgia article in 1990, southern farmers have stacked rocks into cylindrical piles like these within recent history.  In his paper, entitled, “Historic Patterns of Rock Piling and Rock Pile Problems”, Gresham included photographs of such rock piles.  Before 1940, Gresham explained, flat rock and flagstone quarrying in Georgia was “small scale, localized, and done by hand.”  Stones found close to the surface of the ground would be pried up with crowbars, sorted, and stacked for temporary storage until being sold for use building chimneys, terraces, foundations, and steps.  Why, then, would so many such stone piles have survived in Little Mulberry Park?  Perhaps, Gresham proposed, the stone proved inferior for use, and did not sell, or there was some other event that prevented a sale from going forward, or alternative building materials (such as brick) become widely available and prevented the stone from being sold.

Beyond the documented historic occurrence of such piles on North Carolina farms, is there other evidence to support the idea that the structures are historic stone piles rather than prehistoric Indian mounds?   In fact, there is archaeological evidence to support this idea.  In 1995, Thomas Gresham excavated eight stone piles at the Little Mulberry Park site.  He found no prehistoric artifacts, but he did unearth early 19th century artifacts (ceramics, glass, and metal, including an 1838 penny) beneath two of the piles, conclusively showing that both were constructed in historic times.  During the excavation, Gresham’s team also found evidence of a former small-scale rock quarry in the vicinity of the piles, lending further credence to the idea that stone was being cleared from the land and stockpiled in the area.

Ultimately, we will probably never know for certain what cultural forces shaped the stone piles at Little Mulberry Park.  In my own explorations, both on-ground and via the Internet, I am satisfied that the piles are not prehistoric at all, but were built by settlers gathering field stone for future construction efforts.  I suspect that this explanation will be less than satisfactory to many who have visited the park or who read enthusiastically about Mysteries from the Past.  There is a certain allure in thinking that the stone mounds were constructed by Native Americans thousands of years ago as part of a mysterious ritual.  Many human beings are hungry for the sacred, and find solace in the mythical prospect of a distant time when people lived in harmony with nature, leading lives deeply connected to their communities and to the forces animating the cosmos.  To say that the stone piles are actually Indian mounds is, I will admit, a much more enticing story.  And maybe that is why the information sign at the park, rather than proposing several different theories behind the stone structures, instead declares to this day that they are “almost certainly associated with native american cultures.”

Dec 292013
 
Partially stacked stone pile, Little Mulberry Park, 26 December 2013

Partially stacked stone pile, Little Mulberry Park, 26 Dec. 2013

Returning home from my visit to Little Mulberry Park in Gwinnett County, I set to work finding out what I could online about the origin and purpose of the mysterious stone piles I had seen.  Were they “almost certainly associated with native american cultures” as the information sign in the park indicated?  If so, how old were they, and what evidence has been found linking them to prehistory?  The more research I did, the more convinced I became that “almost certainly” is, almost certainly, not an accurate phrase to use.  Indeed, the Little Mulberry Park Master Plan drafted in 2001 did not offer a definitive explanation for the piles, instead noting that “the stacked stone mounds have been variously attributed to pre-Columbian habitation by Native Americans and to post-settlement agriculture….”  Based upon this uncertainty, the master plan added, “it is intended that appropriate interpretive signage will be placed to present the various theories about the mounds” [emphasis added].  Various theories?  What do we truly know about these stone piles, and what is conjecture?  Where is the evidence?

Clearly, I thought, there must be some fairly strong evidence leading archaeologists to conclude that the mounds are prehistoric.  In 1989, the site (officially termed the Parks-Strickland Archaeological Complex) was added to the National Register of Historic Places, where it is listed as a prehistoric site dating from between 499 BC and 499 AD.  According to the National Recreation Trails website (hosted by AmericanTrails.org),  the site’s “pre-historic stone mounds” date to the Middle Woodland period of Native American prehistory, between 100 BC and 500 AD.  Furthermore, “Portions of the stone mounds appear to be patterned to represent a stylized serpent figure which demonstrates careful and consistent techniques of early construction.”  It should be noted that this was the only source I could find that claimed some pattern or structure to any of the mounds, beyond observations that many of the mounds show signs of rock stacking and some are roughly cylindrical in shape.

What evidence is there for ascribing a Late Woodland age to the stone structures, and what do archaeologists think they were intended to be?  It turns out that the mounds were first investigated by Atlanta archaeologist Patrick Garrow, and he is responsible both for raising awareness of the potential cultural significance of the stone piles, and for proposing and strongly advocating that they are pre-settlement in origin.  According to a May 1990 article in the Free-Lance Star, a Fredericksburg, Virginia newspaper, Garrow found over 200 rock mounds, and is quoted in the article as speculating that “I think it was a complex for burial of the dead and a ceremonial complex.”  “But,” he added, “I’m guessing here.  No one is absolutely sure.”  In fact, no Woodland period (or prehistoric in general, for that matter) artifacts were found in or near any of the stone piles, nor were any human remains encountered.

In a 1988 archaeological investigation report by Patrick Garrow and David Chase of Garrow Associates, Inc. (discussed here), the authors gave several arguments as to why the stone piles are likely prehistoric.   While some of the mounds are situated parallel to previous boundary lines, others are not.  If the piles were formed by farmers removing rocks from a field, wouldn’t they collect the stones along a property line, to keep “wasted” land to a minimum?  Also, why would area farmers bother to pile rocks in the first place, since the area was used as pasture and never actually plowed?  Why would farmers clearing a field bother to stack the rocks with so much care?  Finally, the rock piles are not random; many are located at equal distances from each other.  Wouldn’t rock piles formed by farmers clearing their fields be more randomly situated?  (Random, that is, if one overlooks the first idea, that the piles should be preferentially parallel to boundary lines.)  All of these arguments are based upon the rejection of one  alternative explanation for the stone piles: namely, that they could have been the work of post-settlement farmers clearing their land of rocks.  By arguing against this scenario, Garrow and Chase somehow managed to conclude that the piles have to be prehistoric because there is no other reasonable explanation for their origin. In short, there is not one single piece of evidence that the stone piles at Little Mulberry Park are actually prehistoric.  As we shall see in the final installment of this series, however, there is considerable evidence pointing to a different story behind the stone piles.

Dec 282013
 

A few days ago, my wife and I ventured out to a park we had never hiked in before: Little Mulberry Park in northeastern Gwinnett County, Georgia. After circling Atlanta (I hadn’t the courage to attempt the downtown route) and driving for a near-eternity through the northeast suburbs, we arrived at last at the 890-acre park. The property offers a wide variety of trails, including a number of paved multi-use routes, plus a few for horses, bicycles, and pedestrians, and a couple limited to hikers only. We had only a couple of hours before sundown, so I proposed taking the Gorge Trail loop, a 2.16-mile route through an upland hardwood and pine forest and along the edge of a gorge. I was particularly intrigued to read that the trail included over 200 stone mounds, possibly prehistoric in origin.

Setting out on the trail, we soon came to this stunning old oak tree. Its abundant lower branches attest to a time when it stood alone in a pasture, perhaps as recently as 50 to 75 years ago.

This oak tree, perhaps 150 years old, once grew in a pasture.  Little Mulberry Park, Gwinnett County, GA.

This oak tree, perhaps 150 years old, once grew in a pasture. It now stands in a mixed hardwood forest in Little Mulberry Park, Gwinnett County, GA.

After going up and down several steep hillslopes, we began seeing stone piles everywhere we looked.  Some of them were just scatterings of amphibolite gneiss (a metamorphic rock that outcrops throughout the park), while others seemed to be intentionally stacked.  Who constructed them, and why were they there?

Stacked stones on the forest floor, Little Mulberry Park, Gwinnett County, GA.

Stacked stones on the forest floor, Little Mulberry Park, Gwinnett County, GA.

A stone pile from an unknown era shows evidence of deliberate stacking.  But with what intent?  Little Mulberry Park, Gwinnett County, GA.

A stone pile in the forest appears deliberately stacked. But for what reason? Little Mulberry Park, Gwinnett County, GA.

We came to an information sign about the stone mounds, offering an explanation for them and urging visitors to treat them with respect.

Information sign regarding the mysterious stone piles, Little Mulberry Park, Gwinnett County. GA.

Information sign regarding the mysterious stone piles, Little Mulberry Park, Gwinnett County. GA.

The text above asserts that “they are almost certainly associated with native american cultures.”  But if archaeologists “have failed to uncover artifacts”, then on what basis was the connection made?  How do we know that the mounds are prehistoric in the first place?  I will explore this mystery further in my next post.  The answers, as far as I can determine them, teach us  as much about human nature as they do about the landscape history of the upper Piedmont of Georgia.