Archive for July, 2014

The Pennsylvania Mammal Holocaust of 1760–A Rare Record of an Old-Fashioned “Varmint” Drive

July 27, 2014

The old timey pioneers did not appreciate wildlife or wilderness at all.  They saw their environment as a dismal wasteland filled with vermin, a word later Americanized to varmint.  Today, what most consider a beautiful animal was then viewed as a wealth-destroying scourge.  During the 18th century most people didn’t hold large amounts of money in banks but instead measured their wealth in the quantity and quality of the agricultural produce the land they owned produced. There was an economic basis behind their desire to exterminate all competing large mammals because if herds of deer ate their corn or a pack of wolves ripped apart their sheep, they would be financially ruined.  Nevertheless, the methods they used to accomplish this goal of ridding the countryside of varmints seems appalling to modern sensibilities.  One of the methods was known as a ring hunt.  Ring hunts were especially popular in Pennsylvania and Ohio, and settlers used them annually from about 1750-1850.  By the middle of the 19th century, all large wild animals had been completely extirpated from these 2 states.  Ring hunts were popular social events where men got together to enjoy the wonton slaughter of animals.  Few of the participants had any scientific interest in the composition of the animals they killed, and accordingly, the results of most of these murder parties have been forgotten.  However, 1 detailed account has been handed down to us.

A man known as Black Jack Shwartz led a ring hunt in Snyder County, Pennsylvania about 1760.  (Shwartz must have been a charismatic leader because he was previously known to have headed a group of volunteer sharpshooters for General Braddock during the French and Indian War.)  Shwartz organized a group of 200 settlers into a ring surrounding about 30 square miles of wilderness near the Mahantengo Creek, a tributary of the Susquehanna River.  The Mahantengo, translated from the local Indian language, means “where we had plenty of meat to eat.”  The name suggests this region was particularly rich in game, although at this early date wilderness still bordered the young city of Philadelphia, and wild animals ranged throughout the state.  The hunters, standing at intervals about 200 yards apart, made bonfires, rang bells, and fired their muskets into the air, while gradually advancing toward a cleared area in the middle of the circle.  They drove all the wild mammals into the clearing, then shot and killed 1200 of them.  Hundreds of animals did escape.  Faced with a choice between a concentration of wolves, cougars, and bears or puny but noisy humans, hundreds of bison, along with some deer and elk, stampeded through the perimeter and broke free.  This probably explains why the ratio of carnivores in the final talley is so unusually high.  The death toll included 198 white-tail deer, 111 bison, 2 elk, 109 wolves, 112 foxes, 41 cougars, 114 bobcats and/or Canadian lynx, 17 black bears, 1 white bear, 12 wolverines, 3 fishers, 3 beavers, 1 otter, and 500 smaller mammals probably consisting of assorted rabbits, squirrels, possums, raccoons, and skunks.  It seems amazing that such a concentration of wildlife lived in just a 30 square mile area, but other written accounts from Kentucky and Oklahoma also claim high numbers of animals in places prior to the advancement of civilization into formerly pristine environments.

Map of Pennsylvania highlighting Snyder County 

Location of Snyder County, Pennsylvania where pioneers wiped out most of the large mammals within a 30 square mile area in a day.  “Varmint” drives such as this were common in the 18th century, explaining how wildlife rapidly disappeared in the east. 

An albino black bear mother.  The white bear killed in Pennsylvania during a “varmint” drive was probably an albino black bear but may have been a polar bear straggler. (See: https://markgelbart.wordpress.com/2012/09/16/a-polar-bear-ursus-maritimus-fossil-in-breck-smith-cave-kentucky/)

Photo: Wolverine, Gulo gulo.

Wolverines lived in Pennsylvania til about 1865.  A total of 3 were killed in the 1760 circle hunt.

A few choice cuts of meat and a few hides were taken, but most of the dead animals were placed in a pile as “high as the trees.”  This was set on fire, creating a stench that forced some settlers to leave their cabins, even though they lived 3 miles away.  According to the author of the below reference, a mound, within which bones from this mammal holocaust were interred, still marked the site in 1917.  I wonder whether this mound is still there today.

The local Indians were so furious over this destruction of their food supply that they later ambushed and killed Black Jack Shwartz.  They also murdered 12 settlers.  But these murders did not discourage the settlers.  Instead, the settlers continued to hold annual ring hunts, purposefully aggravating the Indians.  The settlers took joy in poking the Indians in the eye.  They held ring hunts as much to insult the Indians as to eliminate varmints.  Ring hunts helped the settlers starve the Indians, while protecting their crops and livestock. 

The concept of a ring hunt is especially revolting to the modern day naturalist.  There are no National Parks east of the Mississippi that host the variety and numbers of wildlife killed in just the 1 ring hunt for which we have a detailed record.  I wish I could live in a wilderness where wildlife was that abundant, yet other people who did have that opportunity chose to destroy it rather than enjoy it.  How ironic.

Reference:

Shoemaker, H.

Extinct Pennsylvania Animals

Altoona Tribune Press 1917

 

 

 

https://archive.org/stream/extinctpennsylva00shoe#page/n9/mode/2up

 

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Humans killed Gompotheres (Cuvieronius sp.) in Mexico 13,390 Years Ago

July 23, 2014

The fossil record suggests Columbian mammoths (Mammuthus colombi) and mastodons (Mammut americanum) were relatively common across North America during the late Pleistocene. Woolly mammoths (Mammuthus primigenius) ranged as far south as Virginia but were more common to the north in Beringia and Eurasia.  Few people are aware that a 4th species of elephant-like beast, the gompothere (Cuvieronius tropicalis), expanded its range to include southeastern North America during warmer climate stages.  The gompothere likely had sparse hair like other large tropical mammals such as elephants, rhinos, and humans.  So when climatic conditions deteriorated, the gompothere’s range contracted toward Central and South America, while the more heavily furred mastodons and mammoths still thrived in regions with subfreezing temperatures.  Prior to 2007, the only evidence that humans hunted gompotheres had been found in South America.  But that year, scientists excavating the El Fin del Mundo site in the Sonoran Province of Mexico discovered 2 piles of gompothere bones eroding from the side of a gulley (or arroyo as known in Spanish).  These bones showed evidence of human modification.

Map of Sonora

Location of Sonora, Mexico.  Gompotheres, a cold intolerant species, still occurred here as late as 13,390 years ago.  They may have ranged into southeastern North America until about 120,000 BP, living alongside the more cold tolerant Columbian mammoths and mastodons.

https://i2.wp.com/keep4u.ru/imgs/b/080805/3b/3bd8f0801f8b69729e.jpg

Illustration of the extinct gompothere.  This species lived in Central and South America and Mexico until the end of the Pleistocene.  During warm climate phases it also colonized southeastern North America as far north as the North Carolina coastal plain.

Gomphothere mandible in place, upside down, at El Fin del Mundo excavation site. The fossil was fully prepared at the INAH zooarchaeology lab in Mexico City.

Lower jaw bones of a subadult gompothere found in the Sonoran Desert, Mexico.

Archaeologists found 27 artifacts associated with the gompothere bones, including flakes in direct contact with the bones.  Some of the bones had been burned, and some of the projectile points were snapped as if they’d broken upon contact.  One of the gompotheres was a juvenile aged 0-12 years old, while the other was a subadult aged 12-23 years old.  The way the bones were arranged into piles also suggests human modification.  Bones found included ankles, feet, limbs, shoulders, jaws, and teeth.  Radiocarbon dating indicates a calender year date of 13,390 years BP, and the artifacts are of the Clovis Culture.  This is the only known Clovis site south of the Rio Grande River.

Scientists believe this site was a freshwater marsh fed by a spring during the late Pleistocene.  Carnivores gnawed on the bones, hooved animals trampled upon them, and then the bones were exposed to the sun long enough to become dessicated, but eventually the marsh mud covered them.    The environment today is much more arid, though sudden showers have contibuted to the erosion of the gulley that has exposed the bones.

 A clear quartz Clovis point found near the bone bed at El Fin del Mundo. Although very difficult to shape into a tool, quartz was used by Clovis tool makers at several sites.

Most of the spear points found at the El Fin Del Mundo fossil site were made from gray chert stone but this one was made from clear quartz.  What a beautiful artifact.

A Clovis camp yielding over 100 artifacts stretches out from 500-1000 meters from the butchered gompothere remains.  Most of the artifacts were made from local chert, but the 1 in the image above was made from clear quartz.

Reference:

Sanchez, G; et. al.

“Human (Clovis)-Gompothere (Cuvieronius sp.) association 13,390 Calibrated BP in Sonora, Mexico”

PNAS 140956111 2014

Melanistic canids, jaguars, and squirrels

July 18, 2014

Melanism in North American wolves is an ancient trait, that according to 1 genetic study, originated from an hybridization event between Eurasian wolves (Canis lupus) and primitive dogs (Canis familiaris).  This occurred at least 46,000 years ago, predating the actual domestication of dogs.  At this early date primitive dogs probably varied from wolves in their preference for living in close proximity to human habitation.  The differences between dogs and wolves then were even less than they are today, and hybridization was much more likely to occur.  Eurasian wolves crossed the Bering landbridge and brought this trait for melanism with them, but curiously, wolves in Eurasia with the trait for melanism died out.  The only population of wolves in Europe today that carry the trait for melanism live in Italy, and this is thought to derive from a much more recent hybridization with dogs.  In North America hybridization between western wolves and dogs no longer occurs in the wild, or at least that’s what the evidence suggests.

Black-coated predators are harder for prey to see in deep shady forests.  Therefore, forested environments provide a natural selection mechanism that favors melanistic individuals.  The incidence of melanistic canids is greater in deep forests than in open environments.  In Alaska dark wolves are rare in open tundra but common in adjacent boreal forests–a great example of natural selection.  Melanism in coyotes (Canis latrans) is extremely rare in western North America but common in the east, especially in the south.  Having darker colored fur is a beneficial mutation for a predator living in the more heavily forested southeast.  

Taxidermic mount of a melanistic coyote killed near Cedartown, Georgia.  This looks identical to the so-called red wolves that were formerly found in Florida.  Is this evidence the wild canids formerly living in the south were not completely extirpated and have bred this melanistic gene into the western coyotes that have colonized the region within the last 50 years?  I believe the wolves that used to live in the south were merely eastern coyote x primitive dog hybrids.

Melanism in eastern coyotes also is derived from hybridization with dogs.  In the past  male dogs mated with  female coyotes and the hybrids backcrossed into the coyote population.  This occurred prior to when coyotes recolonized the south about 50 years ago.  I suspect the southeastern wolves in North America during the time of European colonization were merely hybrids between eastern coyotes and the primitive dogs brought over by Indians about 13,000 years ago.  These primitive dogs, known as the American dingo, readily revert to a wild state, and some likely bred with eastern coyotes during the late Pleistocene/early Holocene.  These hybrids took over the ecological niche left vacant when dire wolves became extinct.  Evidence from 500 year old wolf remains found in Ontario, Canada show the eastern wolf had DNA sequences from both dogs and coyotes but not from western gray wolves.  Yet, morphologically they resembled wolves.  Eastern Canadian wolves probably had a similar origin as southeastern wolves.

Melanism is also common in 2 species of big cats that favor heavily forested environments.  In jaguars (Panthera onca)melanism is conferred through a dominant allele, while in leopards (Panthera pardus) it is conferred through a recessive allele.  When a spotted jaguar mates with another spotted jaguar, the cubs are always spotted.  Cubs from a pairing of a spotted jaguar and a black jaguar can be either spotted or black.  Melanism is also associated with beneficial mutations in the immune system.  This probably also explains the increased incidence of black jaguars in jungles where tropical diseases are prevalent.  Melanistic margays, ocelots, and jaguarundis are known to occur, but no proven specimen of a melanistic cougar has ever been confirmed.  However, cougars in south Florida are grayish, and this coloration affords them a similar advantage enjoyed by completely melanistic cats. 

I hypothesize that Smilodon fatalis, the saber-tooth cat, may have had some melanistic individuals in regions with deep forests.  It was an ambush predator, and a black coat would have made them difficult to spot, especially at night.  Artists rarely portray them with a black coat.  There is enough genetic material at the La Brea tarpits museum to determine whether or not Smilodon carried this trait, but so far, no scientist has thought to look for it.

Melanistic jaguar, showing that markings are visible

Melanistic jaguar–a real black panther.

Fox squirrels (Sciurus niger) are frequently found in melanistic color phases.  One study found that the higher incidence of black color phases in fox squirrels correlates positively with the higher frequency of lightning-induced wildfires in longleaf pine savannahs.  Apparently, the scorched black ground provides camouflage for fox squirrels from 1 of their most common predators, the red-tailed hawk.  Longleaf pine savannahs are often burned annually, and the ground stays black for long enough periods to select for melanistic individuals. 

Melanistic fox squirrel and deer fawn.

Melanistic gray squirrels(Sciurus carolinensis) were formerly abundant when much of North America was covered by shady deep forests.  Today, the black phase of the gray squirrel is still locally common in some midwestern states and CanadaThe black fur conveys an advantage in colder climates, helping the animals warm in the sun.  Individuals of this color phase have been widely relocated, and some populations exist as far south as Kentucky and Washington DC.

References:

Adams, J.R.; and Leonard Waits

“Widespread Occurrence of Domestic Dog Mitochondrial DNA Haplotype in Southeastern, USA, Coyotes”

Molecular Ecology 12 2003

Anderson, J.R.; et. al.

“Molecular and Evolutionary History of Melanism in North American Gray Wolves”

Science 323 2009

Kiltie, R.A.

“Wildfire and the Evolution of Dorsal Melansim in Fox Squirrels, Sciurus niger

Journal of Mammalogy 70 1989

Mowry, Christopher; and Justin Edge

“Melanistic Coyotes in Northwest Georgia”

Southeastern Naturalist  13 (2) 2014

Rutledge, Linda; et. al.

“Genetic and Morphometric Analysis of 16th Century Canis Skull Fragments: Implications for Historic Eastern Gray Wolf Distribution in North America”

Conservation Genetics 2010

Did Eremotherium laurillardi Supplement its Diet with Sea Weed?

July 13, 2014

Eremotherium laurillardi, a species of giant ground sloth, apparently was abundant along the Georgia coast during the Sangamonian Interglacial (~132,000 BP-~118,000 BP).  Fossils of this species have been found at 7 of the 9 known coastal fossil sites of Pleistocene Age. It was really a spectacular beast growing as large as 18 feet long and weighing 6000 pounds.  When it sat on its haunches, it was even taller than a mammoth.  It disappeared from the state when the climate turned colder, probably some time between ~75,000 BP-~30,000 BP.  The fossil record is too incomplete to determine exactly when this species succombed to the cold in this region.  Eremotherium continued to exist in South America until the end of the Pleistocene.  Two other species of ground sloths  were better adapted to the cold and likely lived in Georgia as recently as 11,000 BP.  Jefferson’s ground sloth (Megalonyx jeffersonii) and Harlan’s ground sloth (Paramylodon harlani) were able to survive subfreezing temperatures by denning in underground burrows. (See: https://markgelbart.wordpress.com/2012/10/10/some-giant-ground-sloths-dug-long-burrows/).

eremotherium and human

Size comparison between Eremotherium laurillardi and a man

Eremotherium primarily ate leaves and twigs.  However, I wonder if they supplemented their diet by foraging on seaweed that washed upon the beach.  Because this species frequented the coast, I’m sure they knew how to swim and may have colonized areas of the mainland or islands by crossing waterways with a depth above their head.  Seaweed is high in certain minerals such as iodine and sodium that are lacking in tree leaves.  Modern day tree sloths are known to obtain these nutrients by raiding human septic tanks to feed on feces.  If Eremotherium ate seaweed, scientists should be able to find abrasions on their teeth from munching seaweed with sand adhering to it.  The scientific literature is silent about this detail, but that may be because scientists have never looked for this evidence.

i-f37fe4c608a50b25cc6d49e7bfdc9d9a-toilet_sloth_M-Stojan-Dolar_April-2010.jpg

Two-toed tree sloth, Choloepus didactylus, climbing from a latrine where it just enjoyed snacking on human shit.  The minerals excreted by humans supplement the diet of this species which consists of tree leaves low in sodium.

There was a genus of South America ground sloths that did gradually evolve into an increasingly aquatic existence.  Five consecutive species of ground sloths in the Thalossocerus genus lived on the coast of Chile and Peru between 9 million years BP-4 million years BP.  The earliest species was Thalossocerus antiquus and the last was T. yaucensis T. antiquus had a shorter nose and abrasions on its teeth from eating seaweed with sand adhering to it.  It likely foraged on the beach and in shallow water.  T. yaucensis had a longer nose and no abrasions on its teeth–evidence it swam deeper into the ocean to feed upon kelp that was washed free of sand by the currents.  Moreover, T. yaucensis had greater bone densisty, a characteristic found in marine mammals; and their anatomy suggests they had strong lips for plucking underwater plants.  Manatees have similarly strong lips.  The environment in this region then was mostly desert, so evolving the ability to subsist mostly on seaweed facilitated the survival of this species in an otherwise uninhabitable landscape.  This genus became extinct at the end of the Pliocene during a major marine extinction event.

Thalassocerus sp., a marine ground sloth that lived on the coast of what’s now Chile and Peru between 9 million BP-4 million BP.  Although Eremotherium also lived near the coast, it probably did not swim in the ocean as regularly as this species.

I propose to any vertebrate paleontologists who read this blog, to check your Eremotherium specimens for sand abrasions.  Maybe you can publish a paper about it and thank me for bird-dogging the idea.

Reference:

Amsen, Eli; et. al.

“Gradual Adaptation of Bone Structure to Aquatic Lifestyle in Extinct Sloths from Peru”

Proceedings of the Royal Society of Science 281 (1782) 2014

William Bartram’s Visit to St. Simons Island in 1774

July 10, 2014

I didn’t go to St. Simons Island this summer as I’d initially planned, but I wasn’t disappointed.  I’m sure the island is not as interesting as it was when William Bartram visited it in the spring of 1774.  Bartram stayed for a few days with James Spalding, then the president of the settlement of Frederica and a merchant involved in the Indian trade.  Although a remnant of an old growth maritime forest has been preserved for the modern day naturalist to enjoy, Bartam had the opportunity to see the island when it was mostly undeveloped.  One day, he left Frederica on horseback to survey the island.  Thick groves of live oaks surrounded the town.

500 year old live oak on John’s Island South Carolina.  There may have been quite a few trees of this age on St. Simons Island when Bartram visited in 1774.

Bartram rode through the virgin live oak woods and found a “beautiful green savannah” about 2 square miles in extent.  Long-horned cattle, horses, sheep, and deer fed in this natural pasture.  On the other side of this savannah, he followed an old road that had fallen into disrepair.  The road went through an open woodland of live oaks and longleaf pines spread far enough apart that grass and shrubs could grow in the understory.  The road ended after 5-6 miles when he reached an impenetrable thicket growing on a sandhill.  The thicket was composed of live oak, myrtle, holly, beautyberry, silverbell, alder buckthorn, hoptrees, bully trees, hornbeam, and bignonia.  Several of these species are evergreen and subtropical.  Greenbriar vines covered the thicket, and there was a salt marsh on the other side of the sandhill.  Bartram referred to it as a “salt plains.”

Bartram did find a freshwater creek between the forest and the salt marsh.  Here, he rested and enjoyed the fragrant beauty of diamond frost, morning glory, lycium (a thorny plant in the nightshade family), scarlet sage, and white lily; all of which were blooming in April.

Diamond Frost Euphorbia Diamond frost in the Euphorbia genus.  It is related to the more famous Christmas poinsetta.  This is one of the flowers Bartram saw growing on St. Simons Island.  Actually, it is the leaves that look like flowers. 

Bartram turned south and found the beach where he saw living and dead starfish, corals, jellyfish, snails, whelks, clams, and squid; all washed upon the sand.  He left the uninhabited beach and headed west, coming across 50-60 beehives lined up in a grove of oaks and palms.  He met a farmer and beekeeper who was resting upon a bearskin rug after a morning spent hunting and fishing.  The man gave Bartram venison and honey-sweetened water spiked with brandy.  They had a picnic amidst the mockingbirds, painted buntings, and hummingbrids.  Jasmine, honeysuckle, and azaleas scented the air. 

William Bartram met a farmer and beekeeper on St. Simons Island who was lounging outside on a beer skin rug while drinking brandy mixed with honey and water.  He must have caught the bear raiding his bee hives.

 ©Zachary_Huang 

An apiary.  Beekeepers and bears do not get along.

On his way back to Frederica, Bartram saw many abandoned plantations.  Even Fort Frederica itself, still manned at the time by a small garrison, was falling apart.  Peach, fig, and pomegranate trees grew through the broken walls.  General Oglethorpe had ordered the construction of the fort 60 years earlier, but funds in 1774 were not available to maintain it.

Fort Frederica on St. Simons Island, Georgia.  General Oglethorpe ordered it built circa 1712 to repel any possible invading colonial force such as the Spanish.  By 1774 it was already in ruins.

I envy the bucolic life of the farmer that Bartram met.  The man had half of St. Simons Island to himself.  For an 18th century existence, this was living in paradise.  Poor city folks in London then were lucky if they had bread.  But this man lived on a beautiful plantation with quite a variety of food available from both land and sea.  On the other hand, he didn’t have air conditioning and television.  And the bikini had yet to be invented.  Today, his plantation has been transmogrified into a landscape of condos built as closely together as possible.  If this farmer could visit the present day for a week, I wonder if he would envy our modern life as I envy his or would he wish to return to his old life.  I wonder…would he trade places with me?

The Isle of Hope Fossil Site in Chatham County, Georgia

July 6, 2014

I’ve mentioned the Isle of Hope fossil site numerous times on this blog, but I recently realized I’ve never featured it.  In my opinion it is the 3rd or 4th best Pleistocene fossil site in Georgia, ranking behind Ladds, Kingston Saltpeter Cave, and perhaps Yarbrough Cave.  More vertebrate fossils were discovered here than at any other coastal fossil site in Georgia.  Most other coastal fossil sites were discovered in the 18th or 19th centuries before paleontologists screen-washed sediment for smaller bones, and accordingly the earlier scientists only collected bones of the largest species.  The more recently discovered Clark Quarry near Brunswick may rival the Isle of Hope for best coastal site, but despite the publication of a preliminary report in 2005, the finds at this site have yet to be thoroughly and systematically reviewed in a scientific journal.

The Isle of Hope is an elite neighborhood in Savannah, Georgia.  At high tide, it is separated from the mainland by a small tidal river.  Vertebrate fossils of Pleistocene age have been collected from this river.

The Isle of Hope fossil site was a deposit that occurred on both sides of a small tidal river within the city limits of Savannah.  During high tide this rivulet separates the island from the mainland.  The fossil site was discovered in the early 1980s during construction of a boat pier.  The landowners, and John Heard, an amateur hobbyist, collected the fossils, and later, paleontologists from Georgia Southern also collected specimens from the site.  Most of these specimens are housed at the Georgia Southern Museum.  One side of the site has been “covered in riprap and is no longer accessible for collection.”   However, I suspect this entire tidal river has potential for a hobbyist prospecting for fossils  Tidal action has likely distributed specimens in both directions away from the deposit.  If I lived in Savannah, I’d definitely search for fossils here.

Uranium-series dating and fossil composition suggest the fossils were deposited during a warm interglacial climate phase between ~132,000 BP-~75,000 BP.  Every single species of mollusc and fish found in the fossil deposit still occurs in the region today–evidence water temperatures during this climatic stage were similar to those of today. 

The dwarf surf clam was the most common bivalve species found at the Isle of Hope site.  It is still the most numerically common clam in Georgia tidal inlet channels.

user posted image

Fossil brown-banded wettletraps were found at the Isle of Hope site.

Atlantic sharpnose shark

The Atlantic sharp-nosed shark.  Fossils of this species were the most common fish remains found at the Isle of Hope site.  It’s still the most common shallow water shark found in the region today.

Amazingly, the fishing in coastal Georgia 100,000 years ago would have resulted in the same species typically caught from a modern day pier–sharp-nosed sharks, stingrays, moray eels, sheepshead, black drum, toad fish, and puffers.  Schools of mullet would have been seen swimming by, and little killifish swarmed the shallows.

Eastern mud turtle.  Mud turtles were the most common reptile specimens found at the Isle of Hope site. 

 Photo of Salt Marsh Vole. Photo courtesy of USFWS/Photo by Michael Mitchell.

The meadow vole was the most common small mammal living in coastal Georgia during the Pleistocene.  This species no longer occurs this far south aside from a relic population that lives in a salt marsh in Levy County, Florida.  

There has been an interesting change in the small mammal fauna of coastal Georgia since the Pleistocene.  Then, the most common rodents were the arvicolines, including the meadow vole, southern bog lemming, and Florida muskrat.  The sigmodontine rodents (cotton rat, rice rat, wood rat, and old field mouse) were present but less common.  Today, the 3 arvicoline rodents mentioned above are absent from coastal Georgia while the sigmodontine rodents are common.  The bog lemming no longer occurs this far south.  The meadow vole also doesn’t occur this far south with the exception of a relic population that lives in a salt marsh in Florida.  The Florida muskrat no longer occurs this far north.  Scientists believe the intermingling of warm and cold climate species during the Pleistocene is evidence that climate then was more equible than it is today because formerly winters were warmer and summers were cooler.  I have a different explanation for the co-existence of warm and cold climate species during the Pleistocene.

During some climatic phases, average temperatures were less extreme than they are today, but overall climatic fluctuations were formerly more drastic.  These dramatic climatic fluctuations created more varied habitats that supported a wider array of fauna, especially of small mammals. I think the relatively stable climate of the past 10,000 years is the cause of the more zonal distribution of small mammal species today.  The change in temperature ranges between the Pleistocene and Holocene haven’t been large enough to entirely explain the disappearance of arvicolines from coastal Georgia.  Instead, I think a shift to a more stable climate pattern is a better explanation.  For example, during the Pleistocene a shift to a sudden cold pattern with snowy conditions would have benefited meadow voles over cotton rats because the former are better adapted to living under snow.  A subsequent shift to warm climate would have favored cotton rats, but during Ice Ages the warm climatic phases didn’t last long enough to completely extirpate the cold climate species.  Changes in species composition lagged behind the rapid climatic changes. But over the past 10,000 years, a warm climatic phase that has lasted quite a while, meadow voles did not enjoy the benefits of a sudden shift to cold climate in the south and have mostly disappeared from the region.  Only species adapted to warm climate have been able to continue living in the south.

Perhaps the most mysterious mammal to have lived in Georgia 100,000 years ago was a small cat.  (See https://markgelbart.wordpress.com/2013/05/09/the-mystery-cat-of-pleistocene-georgia/).  A jaw bone of this species was found at this site but not enough skeletal material has been found to determine what species this cat was.  Despite the genus name, Leopardus, it was not closely related to the leopard as some sources have erroneously and carelessly reported (See Roadside Geology of Georgia).  Instead, it was closely related to the margay and ocelot.

White-tailed deer fossils were the most abundant large mammal specimens found here.  Deer may have been more common in Pleistocene Georgia than other species of now extinct megafauna, contrary to other areas such as Florida.  However, specimens of long-nosed peccary, bison, horse, tapir, and mastodon have been found here, showing they did share the environment with deer.  I think if this tidal river were more throughly investigated, fossils of more species would be  discovered, including those of large carnivores which are so far lacking completely from coastal Georgia sites.

Eremotherium laurillardi, the giant ground sloth.  It was common on the Georgia coast during the last interglacial but disappeared from North America some time during the following Ice Age.

Below is a list of all the species found at the Isle of Hope site as reported in the reference cited at the bottom.  I had fun translating the Latin names to English.  Just 1 species of shellfish stymied my attempt to translate them all.

Isle of Hope Species List

Knobbed whelk (Busycon carica)

Brown-banded wettletrap (Epitonium rupicola)

Sea snail (Eupleura caudata)

Lettered olive (Oliva sayana)

Sea snail (Polinices duplicatus)

Eastern auger (Terebra dislocata)

Small white clam (Abra aequalis)

Incongruous ark clam (Anadara brasiliana)

Blood ark clam (Anadara ovalis)

Transverse ark clam (Anadara transversa)

Common jingle shell (Anomia simplex)

? (Divaricella quadrisulcata)

Coquina clam (Donax variabilis)

Dwarf surf clam (Mulinia lateralis)

Ponderous ark clam (Noetia ponderosa)

Atlantic nut clam (Nucula proxima)

3-toothed Cardita (Pleuromeris tridentata)

Nurse shark (Ginglymostoma cirratum)

Sand tiger shark (Carcharias taurus)

Tiger shark (Galeocerdo cuvier)

Bull shark (Carcharhinus leucas)

Dusky shark (Charcharhinus obscurus)

Lemon shark (Negaprion brevirostris)

Sharp-nosed shark (Rhizoprionodon terranovae)

Hammerhead shark (Sphyrna tiburo)

Stingrays (Dasayatidae)

Spotted eagle ray (Aetobatus narinari)

Eagle rays (Myliobatidae)

Gar (Lepisosteus sp.)

Lady fish (Elops saurus)

Moray eels (Muraenidae)

Shad (Alosa sp.)

Herrings (Clupeidae)

Hard-nosed catfish (Arius felis)

Lizard fish (Synodus sp.)

Toadfish (Opsanus sp.)

Ray-finned fish (Batrachoididae)

Killifish (Fundulus sp.)

Sea robins (Prionatus sp.)

Cutlass fish (Trichiurus sp.)

Pinfish (Lagodon rhomboides)

Sheepshead (Archosargus probatocephalus)

Silver Perch (Bairdella cf chrysoura)

Black drum (Pogonias cromis)

Red drum (Scianops ocellata)

Mullets (Mugil sp.)

Barracudas (Sphyraena sp.)

Flounders (Bothidae)

Boxfish (Lactophrys sp.)

Puffer fish (Tetraodontidae)

Porcupine fish (Diodontidae)

Siren (Siren intermedia)

Red Spotted Newt (Notophthalmus viridescens)

Conger Eel (Amphiuma means)

Spotted Salamander (Ambystoma cf maculatum)

Toads (Bufo sp.)

Chorus frog (Pseudacris ornata)

Bullfrog (Rana catesbeiana)

Snapping Turtle (Chelydra serpentina)

Mud Turtles (Kinosternon sp.)

Musk Turtles (Sternotherus)

Soft Shelled Turtle (Apalone ferox)

Box turtle (Terrapene carolina)

Chicken turtle (Deirochelys reticularian)

Slider (Pseudemys cf concinna)

Pond slider (Trachemys scripta)

Gopher tortoise (Gopherus polyphemus)

Extinct Intermediate Tortoise (Hesperotestudo incisa)

Extinct Giant Tortoise (H. crassicutata)

Black Racer (Coluber constrictor)

Bull Snake (Pituophis melanoleucas)

Water snake (Nerodia fasciata)

Queen snake or other Crayfish snake (Regina sp.)

Garter snake (Thanophis sirtalis)

Hog-nosed snake (Heterodon sp.)

cottonmouth water moccasin (Agkistrodon piscivorus)

unidentified rattlesnake (Crotalus sp.)

Unidentified duck (Anas sp.)

Opposum (Didelphis virginiana)

Beautiful armadillo (Dasypus bellus)

Giant ground sloth (Eremotherium laurillardi)

Harlan’s ground sloth (Paramylodon harlani)

Short-tailed shrew (Blarina brevicauda)

Southeastern shrew (Blarina carolinensis)

Eastern mole (Scalopus aquaticus)

Unidentified bear (Ursidae)

Raccoon (Procyon lotor)

River otter (Lutra canadensis)

Margay-like cat (Leopardus sp.)

Bobcat (Lynx rufus)

Southern flying squirrel (Glaucomys volans)

Gray squirrel (Sciurus carolinensis)

Beaver (Castor canadensis)

Rice rat (Orzomys palustris)

Cotton rat (Sigmodon hispidus)

Wood rat (Neotoma floridana)

Old-Field Mouse (Peromyscus polionotus)

Florida muskrat (Neofiber alleni)

Southern bog lemming (Synaptomys australis)

Meadow vole (Microtus pennsylvanicus)

Pine vole (M. pinetorum)

Cottontail rabbit (Sylvilagus floridanus)

Marsh rabbit (S. palustris)

Long-nosed peccary (Mylohyus fossilis)

Bison sp. (Bison sp.)

White-tailed deer (Odocoileus virginianus)

Tapir (Tapirus veroensis)

Horse (Equus sp.)

Mastodon (Mammut americanum)

Reference:

Hulbert, Richard; and Ann Pratt

“New Pleistocene (Rancholabrean) Vertebrate Faunas from Coastal Georgia”

Journal of Vertebrate Paleontology 18 (2) June 1998

 

 

Kites of Southeastern North America

July 3, 2014

I judge the quality of my vacations based on how much wildlife I see.  The best time to view wildlife is early in the morning, but I’m saddled with a late-sleeping teenaged daughter.  I’ve given up even trying to get an early start.  However, at home in Augusta, Georgia, I’ve had better luck lately.  The other day I was jogging on the road in front of my house and thought I saw a pair of cuckoos flying but they went by too fast for me to make a positive ID.  Later that afternoon, I did hear the unmistakeable call of a cuckoo in the woods behind my house and have since heard them twice more. (http://www.allaboutbirds.org/guide/yellow-billed_cuckoo/sounds)  I believe the cuckoos are nesting there.  I hope they eat the hornworms that ravage my tomato plants, and the tent caterpillars that chew up my blueberry bushes.  Cuckoos eat caterpillars that other birds find distasteful. 

One morning, I saw a Cooper’s hawk fly directly toward my back window before veering away.  Red-tailed and red-shouldered hawks are common in my neighborhood, but this was the first Cooper’s hawk I have ever seen in Augusta and I have lived here for 37 years.  During summer, I almost always see Mississippi kites soaring high over me when I’m suffering through my morning jog.  I saw 6 along with a black vulture last Saturday.

Mississippi kite.  Usually, they soar so high, I can’t see their color pattern.

Mississippi kites (Ictinia mississippiensis) are summer residents of southeastern North America.  They winter in South America.  They prey on cold-blooded animals–large insects, frogs, lizards, and snakes.  Kites avoid freezing climates because their cold-blooded prey becomes inactive and unavailable.  Kites catch and eat cicadas and grasshoppers while they are flying…a kind of eat on the go attitude, like Americans eating hamburgers and French fries while they are driving their cars.

Swallow-tailed Kite Photo

Swallow-tailed kite.  I saw one of these once in Jenkins County, Georgia.  It was also soaring very high in the sky.

I’ve seen a swallow-tailed kite (Elanoides forfincatus) just once–in Jenkins County, Georgia.  They were formerly common, spending summers as far north as Minnesota.  Like Mississippi kites, they winter in South America.  Swallow-tailed kites were known for eating the insects and reptiles fleeing ahead of the annual fires that burned through pine savannahs.  Up until well into the 20th century, it was popular for people to shoot birds for the hell of it, and these callous hicks devastated swallow-tailed kite populations.  Swallow-tailed kites have been completely eliminated in North America outside of the south, and they are considered rare within this region.

Image of Snail Kite

The snail kite is a South American bird that ranges into south Florida.

The snail kite (Rostrahumus sociabilis) eats nothing but snails.  It lives in south Florida and central and South America and does not migrate.  In Florida the snail kite feeds upon apple snails.  It seizes the snail with its talons, then waits patiently for the snail’s head to emerge from the shell.  It quickly grabs the snail’s head with its beak and tears the body loose.  Snail kites are increasing in number, thanks to an abundance of invasive snails.  Snail kite populations have doubled in the 10 years since the Island apple snail, a South American native, escaped from aquariums.  In 2010 a scientist from the University of Florida published a stupid study claiming the introduction of the Island apple snail would cause the snail kite to become extinct in Florida within 30 years.  The author of this study suggested the kites would expend too much energy trying to exploit the larger snail.  However, snail kites in South America thrive on this snail, and the author of this  study saw his illogical conclusion debunked by the facts immediately. Most invasive species are considered destructive, but the introduction of the Island apple snail is a case of a beneficial invasion.  Besides snail kites, limpkins, another snail-eating bird, have increased in the past few years. Island apple snails even eat invasive hydrilla, a plant that clogs waterways all across the south.  Before the Island apple snail invasion, wildlife officials were afraid the Florida population of snail kite was headed for extirpation. 

adult

The white-tailed kite has a curious distribution, living in south Florida, south Texas, Mexico, Central America, and the Pacific coast.

White-tailed kites (Elanus leucaras) were absent from Florida between 1930-1985.  Hunters had eliminated this population.  But they have since recolonized Florida.  This kite has a curious distribution, living year round in south Florida, south Texas, Mexico, Central America, and the Pacific coast.  At some point during the Pleistocene, this bird probably had a continuous range.  The white-tailed kite is a species that requires prairie habitat.  During some climatic phases, a grassland corridor connected the eastern and western populations, but the area in between has since become forested.  In this respect it is similar to many other species such as the burrowing owl, scrub jay, brown-headed nuthatch, and diamondback rattlesnake that have separated eastern and western populations.

Kites are absent from the fossil record of southeastern North America, but undoubtedly they’ve lived here for millions of years.  Kites just happen to live in environments where they are not likely to become preserved.  They avoid caves and rarely die in a river–the 2 processes most likely to preserve them.  Fossil evidence of Mississippi kites has been found in northern Mexico.  Genetic evidence suggests different migratory populations of Mississippi kites diverged early during the Pleistocene and have not interbred since.  They’ve been spending summers in what’s now known as Georgia since before Homo sapiens existed as a species.