Inland Shorebirds of the Pleistocene

The Scolopacidae family includes birds that are commonly considered denizens of the sea shore, such as sandpipers and curlews, but 3 species are primarily terrestrial inhabitants.  The upland sandpiper (Bartramia longicauda), also known as the golden plover or Bartram’s plover, is the one most easily recognizable as a relative of its familiar sea shore cousins.   However, it preferes grassy environments where it feeds upon insects and grass seeds instead of marine worms, clams, and fiddler crabs.  Upland sandpipers were formerly an abundant bird of the prairies on the Great Plains and in the midwest, but market hunting destroyed the primeval population, and farmers replaced prairie grasses with fields of wheat and corn that are unsuitable habitats for this bird.  In March 1821 just 1 market hunter killed 48,000 upland sandpipers, demonstrating how abundant they used to be.  (They were regarded as a delicacy by Creole cooks.)  This bird will never regain its former abundance, but the remaining population is adapting to new anthropogenic grasslands–abandoned strip mines and airports.  

Upland sandpiper.  They are a ground nesting bird that feigns injury to draw predators away from their eggs and nestlings.

The upland sandpiper is a summer migrant to North America, and it winters on the Pampas of South America.  Aside from an occasional vagrant, this bird is presently absent from the southeast, but it was a common species in this region during the Pleistocene.  Fossil evidence of upland sandpipers, dating to the late Pleistocene, were found in Kingston Saltpeter Cave, Bartow County, Georgia and in Bell Cave in Northern Alabama.  This geographical area was mostly forested then, but extensive grasslands must have also existed because upland sandpipers favor nearly treeless habitats.

Both the above mentioned fossil sites yielded remains of the woodcock (Scolopax minor) as well, another terrestrial member of the Scolopacidae.  This bird uses its unusually long bill to probe moist earth for worms and grubs.  They are year round residents in the south, but much of the population migrates north for the summer.

Woodcock.  In Ohio they are arriving a month earlier in spring than they did 100 years ago due to global warming.

Woodcocks spend their days hiding in the woods but feed in open areas at night.  They favor 2nd growth woods with thickets that are adjacent to agricultural fields where they can hunt for earthworms in the tilled soil.  Like upland sandpipers, woodcocks are much less common than they used to be because of hunting and habitat loss.  In the Pleistocene south woodcocks likely were abundant because megafauna foraging and sudden climate fluctuations created mixed environments of young and old forests, thickets, and grasslands.  Moreover, large predators such as wolves and big cats kept numbers of foxes, raccoons, and possums relatively low, reducing nest predation.  The south was a refuge for woodcocks during the height of the Ice Age.  Genetic studies suggest the woodcock population expanded rapidly following the retreat of the glaciers as more habitat became available.

Male woodcocks display by making a “peent” call before flying in wide spirals above their potential mates.  The females lay eggs on the ground and carry their young with them for 18 days until the nestling learns to fly.  Then in late summer when they moult, woodcocks can’t fly and must hide in thickets, thus explaining why they need varied habitats.

Wilson’s snipe (Gallinago delicata) is another species of terrestrial Scolopacidae.  They live and nest in marshes where they hunt for worms, grubs, insects, and some plant matter.  They are an erratic fast flyer, making them difficult to shoot, hence the origin of the word, sniper.  Wilson’s snipes have a curious pattern of migration.  They winter in the southeast as well as in South America and migrate over dry land in the late winter and early spring.  But when they migrate south, they travel over the coast.  This explains why there are an additional 9 species of snipe endemic to various islands.  Storms blew some flocks off course where they found permanent refuge on isolated oceanic islands.

Wilson’s snipe–a marsh bird.  Their habit of migrating south over the coast has resulted in speciation on isolated islands.

Even some coastal species of Scolopacidae occasionally find their way far inland.  Joel McNeal photographed stilt-legged sandpipers, lesser yellowlegs, black necked stilts, pectoral sandpipers, long-billed dowitchers, American avocets, western sandpipers, and semi-palmated sandpipers foraging on the sod farm that surrounds the Etowah Indian Mounds in Bartow County.  Here’s a link to his photos. http://www.pbase.com/joelmcneal/bartowbirds

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The Nature of the Picayune Creole Cookbook

In honor of Thanksgiving, the American holiday dedicated to gluttony, I offer this food-oriented essay.

Editors and journalists from the New Orleans Picayune newspaper published the Picayune Creole Cookbook in 1901 from recipes compiled in the late 19th century.  If the reader is interested in this cookbook, be sure to purchase the facsimile of the original published by Dover Publications and not the newer version published by Random House in 1987.  The ignorant clods who updated the original left out most of the historical recipes that made the original so unique and valuable for food historians.   The text of the original version is available for free online from the following link http://archive.org/stream/cu31924073878708/cu31924073878708_djvu.txt

The great variety of organisms consumed by Creoles during the 19th century makes the Picayune Creole Cookbook  an interesting one for naturalists as well as food historians.  Today, turtles are a regional specialty but have gone out of culinary style for most of the United States.  For 19th century Americans, turtle meat was an abundant and common source of protein.  The Picayune Creole Cookbook gives recipes for green sea turtles and diamondback terrapins.

Diamondback terrapin.  Reportedly a delicacy.

Diamondback terrapins live in saltmarshes all along the Atlantic coast from New England to Mexico.  Like so many other animals, they were formerly abundant but today are rare due to human consumption and coastal development.  I’ve never seen one.  Turtles were cooked in soups and stews, giving me the impression the meat is tough.  Turtle meat is not sold in stores around Augusta, Georgia and I’ve never eaten turtle.

The sheepshead was the most popular and “versatile” fish used in New Orleans around the turn of the century.  This species uses its human-like teeth to crush the shellfish that it feeds upon.  This diet is probably what makes them taste so good.

The teeth on a sheepshead look very human-like.  They eat clams and the teeth crush the shells.

Look at that beautiful…fish!

The Picayune Creole cookbook also has 5 recipes for eel, 4 for stingray, and 6 for frog.  Oddly enough, the only recipe for a freshwater fish species is for roe from green trout which is the name they used then for largemouth bass.  Most of the fish recipes are for marine species including pompano, bluefish, flounder, red snapper, red drum, and croaker.

One of the most interesting dishes in the book is Pigeon a la cardinale, known also as pigeon and crawfish–a combination I bet not a single person in the world will eat for supper tonight.  The dish calls for baking 3 pigeons between layers of bacon in a pan filled with beef broth and onions.  The crawfish are boiled separately.  After the pigeons and crawfish are done cooking, a little of the crawfish boil water is added to the beef broth and the pigeons are garnished with the crawfish.  The authors of the cookbook differentiate between domestic and wild pigeons.  The availability of passenger pigeons at the market was still a recent memory when they were compiling the recipes for this book.

The Picayune Creole Cookbook states that the pigeon and crawfish dish is “Creole to the letter.”  Now this dish is almost unheard of.  The above photo is the closest match I could find on google images.  It’s a roasted pigeon served with crawfish tails, softshelled crab, and vegetables, but not with bacon and a gravy made from pigeon, beef, and crawfish broth.  Passenger pigeons and crawfish were at one time both abundant, making pigeons and crawfish a practical dish.  Now, it’s not at all economical to make.

The canvasback duck (Nyoca vallosneria) was praised as the best-eating waterfowl because it ate wild celery (Vallosneria spiralis).  Some ducks eat a lot of fish, but canvasbacks are mostly vegetarian.  This diet gives their a flesh a savory quality.  They were simply seasoned with salt, pepper, and lemon juice and broiled quickly.

Male and female canvasback ducks–reportedly the best tasting of all ducks.  Duck is one of my favorite foods.

The bobolink (Dolichonyx oryzivorous) known as the reedbird in the Picayune Creole Cookbook, apparently was common table fair when in season. The second part of its scientific name means rice-devourer.  It still is a pest for rice farmers.  Creoles shot these members of the blackbird family to protect their rice fields.  It only takes 5 minutes to broil small birds such as bobolinks (robins and larks were also prepared this way).  I’ve never eaten a bird smaller than a quail.  It takes at least 2 quail to equal the amount of meat from about 1/4th of a chicken.  It probably takes about 4 bobolinks to equal 1/4th of a chicken.

The bobolink, also known as the rice bird.  It’s a pest to rice farmers and table fair for Creoles.

It took me a while to figure out what a pababotte was.  I’ve determined that the pababotte discussed in the Picayune Creole Cookbook is probably the upland sandpiper (Bartramia longicauda).  The upland sandpiper is a denizen of the prairie.  Fossil specimens of this species were discovered at Kingston Saltpeter Cave in Georgia and Bell Cave in Alabama.  Both localities are in a region where upland sandpipers are absent today aside from an occasional vagrant.  This is evidence that small pockets of prairie existed within the mostly forested region of the upper south during the late Pleistocene.  Upland sandpipers were once an abundant bird but overhunting and agriculture have greatly reduced their numbers.  J.J. Audubon witnessed 48,000 upland sandpipers killed in a single day by a group of hunters in 1810.  Creoles serve them stuffed and braised, roasted, or broiled.

Upland sandpipers were more widespread during the Ice Age.

Until 1861 an old French woman produced Fois Gras in New Orleans.  She raised geese in small cages.  She kept their feet nailed to the cage floor and force fed them to enlarge their livers.  I’m sure the enlarged livers are rich and delicious, but the practice seems cruel and wasteful–the rest of the meat is flabby and unfit for eating.  Raising geese for Fois Gras is illegal in the U.S. today.

There are many recipes in the Picayune Creole Cookbook that don’t require extinct or rare animals to make.  One of the best I’ve tried is a soup made out of beef ribs, corn, and tomatoes.  I could live on lentil salad–a simple recipe of lentils tossed in a vinegarette.  The gumbo recipes from the book use less roux than most modern gumbos and instead are thickened with powdered sassafras leaves or okra.  A gumbo made out of a leftover turkey carcass is an excellent example of frugality but I prefere a more roux-heavy version.  There are 7 recipes for different types of sausages, and I’ve made several, though in the shape of hamburger patties rather than links stuffed in casings.  For the home cook I think this book is still useful and will never go out of date.

The Extinct Vero Tapir (Tapirus veroensis)

When I first began studying the scientific literature on Pleistocene mammals in 1988 I excitedly told my little sister and my now ex-brother-in-law that tapirs and capybaras used to live in Georgia.  Neither knew what a tapir or capybara was, and they looked at me like I was nuts.  This happened before the days of the popular internet, and I couldn’t readily show them photos of the animals on a computer screen.  Another great benefit of the internet is that I can communicate with people who actually care and also share my interest.

Mountain or woolly tapir (Tapirus pinchaque).  Of the 4 species of tapir in the world, this is the only one that inhabits a temperate forest.  The others are tropical.  The extinct Vero tapir also inhabited temperate forests as far north as what today is Kansas.  Like the Vero tapir, the mountain tapir is likely headed toward extinction.  There are only 9 in zoos and less than 2500 in the wild.

Jaw bone of a Vero tapir.  The partial jaw of a tapir is the only Pleistocene fossil reported from Anderson Spring Cave in Walker County, Georgia.  The ridged teeth are evidence they browse rather than graze.

View from inside Anderson Spring Cave, Walker County, Georgia.  The jaw bone of a tapir was found here.  Photo by Kelly Smallwood.

The type specimen of the Vero tapir was found in Vero Beach, Florida in 1915, and it was associated with human bones dating to about 14,000 BP–a find that caused considerable controversy at the time because mainstream archaeologists refused to believe humans lived in North America prior to 6,000 BP.  Apparently, the Vero tapir was a fairly common species in the Pleistocene southeast.  In Georgia fossils of the Vero tapir have been found at Ladds Mountain, Bartow County; Anderson Spring Cave, Walker County; the Isle of Hope site and Savannah River dredgings in Chatham County; and at Watkins Quarry in Glynn County.  Northern Alabama fossil sites produced tapir bones too.  Both Cave ACb-3 and Bell Cave were the final resting places for a few tapirs.  In the latter site tapir fossils were associated with caribou and long-nosed peccary bones–what an odd mix of ungulates.  This suggests the Vero tapir was a temperate species, capable of surviving subfreezing temperatures.  The still extant (though probably not for long) mountain tapir lives in cloud forests above 6500 feet in elevation in Peru, so it’s not all that unusual for a tapir species to live in a temperate climate, though the 3 other living species inhabit the tropics.

Extant tapirs are big strong animals weighing up to 600 pounds.  The Vero tapir was slightly larger than this, and it must have been a tough creature able to fend off big cats, wolves, and bears.  When cornered they bite and put up a ferocious battle, but more often they shake off their attackers by running through dense vegetation or diving into deep water.  Their tough hides keep them from getting scrapes and abrasions while stampeding through brush.  A recent television documentary on National Geographic Wild showed film of vampire bats feeding upon tapirs which ignored the pesky bloodsuckers.  Deer were much more sensitive and vigilant about keeping the bats from biting them, perhaps explaining why vampire bats are extinct in North America.  The bats need beasts with thick skins that can’t detect them.

The tapir’s unusual looking and prominent proboscis is utilitarian.  It’s prehensile and used to grip and strip branches of leaves.  They eat forest vegetation such as ferns, leaves, and succulent plants.  Their preferred habitat is moist woodlands and river bottomlands.  During the Pleistocene whenever climatic conditions favored the spread of woodlands tapir populations in southeastern North America probably expanded.  Unfavorable climatic conditions probably limited them to riverine corridors.  Modern tapirs are considered keystone species because they’re important seed dispersers.  Wax palms and highland lupines decline in abundance whenever mountain tapirs are hunted out of a region.  Certain plant species were likely more abundant during the Pleistocene,  thanks to the Vero tapir’s inefficient digestive system.  Some unknown species of plants may have even become extinct after tapirs were gone.

The terminal radiocarbon date for the Vero tapir in southeastern North America is 11,450.  This translates to a calender year date of 13,300 BP.  They probably lasted in isolated pockets for 2 or 3 thousand years longer, but they’ve been gone a long time now.  The mountain tapir has been discussed as a candidate for Pleistocene rewilding in North America.  This won’t happen.  The mountain tapir is expected to become extinct in the wild by the end of the decade.  It needs continuous stretches of cloud forest–patchy forests are inadequate.  All captive individuals are descendents of 2 individuals, so it will inbreed itself to death in zoos as well.  Last month, black rhinos were declared extinct in the wild. Our modern forests are already impoverished and devoid of diversity.  The loss of yet 2 more species of megafauna is unspeakably sad.

The Beauty of Pleistocene Swans (Cygnus buccinator)

Photo from google images of a trumpetor swan.

No animal symbolizes the beauty of the Pleistocene more than the trumpetor swan (Cygnus buccinator).  I suppose we can consider it a stroke of good fortune that this species didn’t become extinct with the spectacular megafauna of that bygone era.  Contemporary efforts to protect the bird and help re-expand its range have even been moderately successful.

Modern range map of the trumpetor swan.  It occurred as far south as South Carolina during colonial times.  During the Pleistocene there was likely a sizeable population of this species in the southeast where it is completely absent today.  Fossils of this species have been recovered from northern Alabama and Florida.  Overhunting by men extirpated this species from much of its former range.

Before European settlement of North America trumpetor swans were more common and widespread, migrating as far south as South Carolina during severe winters.  But during the Pleistocene they ranged even further south.  Bell Cave in northern Alabama and several sites in Florida have yielded fossils of this bird.  Ice Ages provided ideal habitat for this species.

Audubon mentions that trumpetor swans prefer a moderate climate.  Ice Age summers in the south were generally cooler and winters were still moderate, so swans would have had a favorable climate in this region then.  It seems likely that Pleistocene trumpetor swans bred and nested on the abundant glacial lakes near the boundaries of the great ice sheets. Then during winter they didn’t have far to migrate because the distance between glacial lakes and favorable wintering habitat in the south was much less than the distances they have to travel today.  Perhaps a segment of the population remained and nested in the south year round, much like modern day sandhill cranes of which some migrate and some are permanent residents.

Map of the Laurentide glacier.   During the LGM swans didn’t have far to migrate between summer nesting grounds near glacial lakes and winter habitat in the south.  Some segments of the population probably lived year round in the south.

Swans inhabit ponds and small lakes with aquatic plants growing on the bottom upon which they feed. Extensive beaver ponds and marshes, and oxbow lakes were the kinds of abundant habitat in the south available to the big birds then.  Swans nest and take cover on beaver dams, muskrat lodges, and islands where they’re relatively safe from mammalian predators. If hungry enough, mammalian carnivores will expend the energy to swim and search for food in wetlands, but it’s not their first choice when looking for an easy meal.  During stadials, islands on braided rivers were common, giving swans lots of favorable habitat.  This wouldn’t have kept swans safe from eagles, however.

Photo from google images of a bald eagle killing a swan.  Eagles of several kinds were common during the Pleistocene.

Grinnell’s crested eagles, golden eagles, and bald eagles were capable of hunting and killing swans during the Pleistocene.  But swan defense mechanisms were adequate enough to maintain substantial populations.  Swans weigh up to 30 pounds and a blow from their wing is powerful enough to break human bone.   They can also flee by submerging and swimming for some distance.  They’re most vulnerable to eagles and human hunters when in flight.

Swans have an interesting method of feeding.  While they swim on the water, they lower their long necks to reach the aquatic plants growing on the bottom.  Because they have longer necks than geese, they can outcompete them for food by eliminating all the fodder within a goose’s reach.  Swans also graze grass on land; and they eat snails, reptiles, and small mammals.

What was the Deer-Hunting like in Pleistocene Georgia?

Deer-hunting season begins in Georgia this month.  The only native species of deer modern hunters can hunt in state is the white tail deer (Odocoileus virginianus) which numbers close to 1.2 million, making it the second most common large mammal in the state, behind man.  This season, hunters are allowed to take an astonishing 10 antlerless and 2 antlered deer, suggesting either a shortage of hunters or an overpopulation of deer.

The fossil record provides evidence that white tail deer were a common large mammal species during the Pleistocene too.  Their bones are found in almost all Pleistocene-dated sites in state.  They’re a species that prefers forest edge habitats, and the dynamic ecosystems of the Ice Age with fire, rapid climate fluctuations, and megafauna  destruction of trees, created extensive areas of this type of habitat.

Photos I took of white tail deer at Fripp Island, South Carolina.  The deer here are numerous and have little fear of humans.  Nevertheless, they should not be approached or fed because they are unpredictable wild animals and dangerous.  They can use their hooves to stomp people.  Deer have been known to kill dogs.

I suspect elk (Cervus canadensis) may have been the second most common kind of deer in what’s now Georgia during the Ice Age, ranging as far south as the fall line between the piedmont and the coastal plain.  Elk fossils from Kingston Saltpeter Cave in north Georgia, and near Charleston, South Carolina are the southernmost record of this species.  None have been found in Florida’s abundant fossiliferous deposits.  I think this is evidence of an abrupt difference in climate between the piedmont region of southeastern North America and the coastal plain.

Scientists don’t know much about the extinct fugitive or stilt-legged deer (Sangamona fugitiva).  It was like a white tail deer but approached an elk is size, maybe being slightly smaller.  The deer lived in east central North America from Missouri to West Virginia and a definitive record comes from Hamblen, Tennessee.  It probably occurred in northern Georgia because Dr. Clayton Ray found a tooth that may or may not have been from this species–the specimen was in too dodgy a condition to identify with certainty.

That caribou (Rangifer caribou) lived in northern parts of southeastern states during the Ice Age fascinates me.  Caribou fossils discovered in Bell Cave, Yarbrough Cave in Georgia, and near Charleston, South Carolina are evidence this species lived much further south than it did in historical times.  Were they stragglers or members of large migrating herds that regularly travelled through Georgia?  I wish I knew.

The stag-moose, or elk moose (Cervalces scotti) is kind of misnamed for it wasn’t closely related to a moose or an elk.  It was named so because it slightly surpassed a moose in size and sported antlers similar to those of the elk.  However, it was a distinct species, now extinct.  Its fossils are occasionally found in places like Ohio or New York.  One tooth of this species was discovered in Magnolia Phosphate Mine near Charleston (as I noted in a previous blog entry about the site)–evidence a small population roamed the upper south.

Pleistocene venison may have had a bitter flavor.  According to pollen records, wormwood (Artemesia) flourished more abundantly in the south than it does today.  This plant still commonly occurs in western localities, such as in Yellowstone National Park.  Reportedly, game that’s been eating wormwood acquires a bitter taste.  I can attest to the fine qualities of wild Georgia white tail deer meat–it tastes like dry beef, and I think the wild venison is better than New Zealand farm-raised animals, which though also good, tastes more like lamb.

Pleistocene Passenger Pigeon Populations

(Please forgive the excessive alliteration in the title.)

It’s hard to imagine the massive number of passenger pigeons (Ectopistes migratorius) that used to live in North America as recently as the mid to late 19th century.  For a description of their numbers, I’ve dug up an account J.J. Audubon gave in his Ornithological Biography.  Before I reprint this passage I want to comment on his writing style.  I enjoy his prose, but he does have a bad habit of writing in the passive voice, a style Stephen King in his book, On Writing, referred to as farting in an elevator.  Also, English was his second language because he was born in France.  Nevertheless, I think this makes for a fascinating description of a nature scene that no longer exists.

“The multitudes of wild pigeons in our woods are astonishing.  Indeed, after having viewed them so often, and under so many circumstances, I even now feel inclined to pause, and assure myself that what I am going to relate is fact.  Yet I have seen it all, and that too in the company of persons, who, like myself, were struck with amazement.

In the autumn of 1813, I left my house at Henderson, on the banks of the Ohio, on my way to Louisville.  In passing over the barrens a few miles beyond Hardensburgh, I observed the pigeons flying from north-east to south-west, in greater numbers than I thought I had ever seen them before, and feeling an inclination to count the flocks that might pass within the reach of my eye in one hour, I dismounted, seated myself on an eminence, and began to mark with my pencil, making a dot for every flock that passed.  In a short time finding the task which I had undertaken impractical, as the birds poured in countless multitudes, I rose, and counting the dots put down, found that 163 had been made in 21 minutes.  I traveled on, and still met more the farther I proceeded.  The air was literally filled with pigeons; the light of the noon-day was obscured as by an eclipse; the dung fell in spots, not unlike melting flakes of snow; and the continuing buzz of wings had a tendency to lull my senses to repose…

“It may not, perhaps, be out of place to attempt an estimate of the number of pigeons contained in one of those mighty flocks, and of the quantity of food consumed by its members.  The inquiry will tend to shew the astonishing bounty of the great Author of Nature in providing for the wants of his creatures.  Let us take a column of one mile in breadth, which is far below average size, and suppose it passing over us without interruption for three hours, at the rate mentioned above as one mile in a minute.  This will give us a parallelogram of 180 miles by 1,  covering 180 square miles.  Allowing two pigeons to the square yard, we have one billion, one hundred and fifteen million, one-hundred and thirty-six thousand pigeons in one flock.  As every pigeon daily consumed fully half a pint of food, the quantity necessary for supplying this vast multitude must be eight million seven hundred twelve thousand bushels per day.”

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Some archaeologists believe the massive population of passenger pigeons that colonists in North America reported from 1700-1870 was a temporary phenomenon.  Thomas Neuman has written at least two journal articles suggesting passenger pigeon populations exploded following the decimation of Indians after their first contact with European diseases such as smallpox, influenza, and measles.  Before this, Dr. Neuman believes this species was not particularly common.  Supposedly, when Indian populations were reduced, there was more forest mast available for birds because humans weren’t gathering the nuts and acorns they fed upon.  In his book 1491 Charles Mann discusses this theory and notes that archaeologists find few passenger pigeon bones at sites of large Indian settlements.

I disagree with this theory because it makes little sense for several reasons which I shall enumerate.

1. Passenger pigeons could not survive as a species unless they existed in extremely large populations.  The survival strategy of this species was to reproduce rapidly and roost and nest in enormous colonies so that they overwhelmed predation.  Predators ate many individuals, but there was a limit to how much their stomachs could hold.  If, as these archaeologists suggest, the passenger pigeon was just an occasional bird, the species would’ve become extinct long before the white man arrived on the continent because their defense mechanisms revolved around living in large colonies.

2. Even if human populations were at the high end of what archaeologists believe, they would’ve made little impact on the amount of forest mast available.  Pre-Columbian forests were extensive, and there was always plenty of forest mast for both humans and huge pigeon colonies.

3. Archaeologists don’t find many passenger pigeon bones in sites of large Indian settlements because Indians probably went to their roosting grounds and feasted on them there and simply didn’t bring the bones back to their villages.

4. Jacques Cartier, an early explorer, reported large pigeon colonies on Prince Edward Island in 1534…before Indian populations were reduced by disease.

5. Pigeon fossils are abundant in an early Holocene fossil site in Western Canada (Charlie Lake, British Columbia).  They are also a common fossil in late Pleistocene avifaunas including Bell Cave, Alabama, Cheek Bend Cave, Tennessee, and Ladds and Kingston Saltpeter Cave in Georgia.

At Ladds fossils of only 4 bird species were discovered.  Passenger pigeons were 1 of the 4.  This may be coincidence, but it’s believed that passenger pigeon biomass made up 25% of all bird populations in North America during the early part of the 19th century.  Many more species of birds were found in the deposit at Kingston Saltpeter Cave.  I compared the minimum number of individual passenger pigeon fossils from KSC to the total bird remains of all other species found there.  Ruffed grouse were the most common species, making up 30% of bird remains, but passenger pigeons made up 6%, despite being a highly migratory bird.  Assuming they spent 6 months of the year around KSC, that means at times, they may have made up to 12% of the bird population in the area.  If they stayed in the area around the cave for only 2 months of the year, they quite possibly made up 36% of the bird population at certain times of the year there.

I must mention, however, that estimating ancient bird populations based on the number of bird fossils found in cave deposits is a rather dubious method.  Nevertheless, habitat for passenger pigeons in southeastern North America during the Pleistocene must have been ideal for this species.

During colonial times this bird nested throughout the midwest, but spent September-February in southeastern states.  For much of the duration of the Wisconsin Ice Age, most of the area where they later nested was under glacial ice, so it’s likely their nesting areas shifted south.  They probably were year round residents everywhere south of the Laurentide ice sheet, except during nesting season when they nested in southern river bottomlands where beech and oak trees remained plentiful, even during cold arid climatic phases.

Today, beech trees are a rare relic in much of the southeast, but during certain climatic phases of the Wisconsin Ice Age, they were even a dominant tree on some lands, according to records of fossil pollen in Alabama, and South Carolina.  From 14,000-11,000 years BP beech was a common tree, while pine, which dominated southern forests during the LGM, temporarily declined drastically.  Beech is well adapted to pigeon and squirrel foraging because this tree spreads through sucker roots, and if animals eat the tree nuts, this species can still propagate.  Beech tree pollen is also present in the Nodoroc fossil site in central Georgia near Winder and at the Gray’s Reef site off Sapelo Island, which was above sea level 30,000 years ago.  The latter site yielded evidence of a forest consisting of a strange mixture of cool temperate and warm weather species of plants.  The south’s Ice Age ecosystem was a mixture of woodlands and grasslands, and it provided excellent habitat for passenger pigeons.  I think the expansion of southern beech tree forests, as the Ice Age waned, is evidence the population of pigeons may have spiked about 14,000 years BP, creating the nucleus that later colonized the midwest after the glacier melted and broadleaf trees re-established themselves there.

References.

Driver, J.C.; and K.A. Hobson

“A 10,500 year sequence of bird remains from the southern boreal forest region of western Canada”

Arctic 45 (2) 1992

Ellsworth, Joshua; and Brenda McComb

“Potential effects of Passenger Pigeon flocks on the structure and composition of pre-settlement forests of eastern North America”

Conservation Biology 17 (6) pp. 1548-1558 2003

Mann, Charles

1491

Knopf 2005

www.paleodb.org