Posts Tagged ‘passenger pigeon’

The Curious Disjunct Range of the Miccosukee Gooseberry (Ribes echineiium)

April 25, 2012

The Miccosukee Gooseberry grows in just 2 counties hundreds of miles apart.  One population clings to the shoreline of Lake Miccosukee in northwest Florida, and it numbers about 5,000 individuals.  The other population lives in McCormick County, South Carolina near the eastern border of central Georgia 1.5 miles north of Clark Hill Lake.  In this county there are 2 separate populations: 1 group is in Sumter National Forest and the other is located in the Steven’s Creek Heritage Area.  The McCormick County population is estimated to number between 13,000-160,000 bushes.

Leaves, flowers, and twigs of the rare Miccosukee Gooseberry.  I couldn’t find a photo of a whole bush on the web.

I suspect the Miccosukee gooseberry had a wider, more continuous range during the Pleistocene and maybe as recently as the Colonial era.  I hypothesize its decline to relict status is probably tied to the extinctions of the mastodon and the passenger pigeon.  Several clues support my hypothesis.  Notice the remaining populations grow near water.  They grow near the shore of Miccosukee Lake in Florida, and on a steep north-facing slope along Steven’s Creek.  Mastodons were semi-aquatic, and passenger pigeon flocks roosted along water ways.  The surviving colonies are likely remnants of once larger colonies that thrived thanks to the bio-activities of mastodons and passenger pigeons.  Mastodons facilitated the growth of gooseberries by eating branches and leaves of overstory trees, thus allowing more sunlight to reach the low growing bushes which don’t exceed 3 feet in height.  Mastodons helped spread gooseberries by eating the bushes–the pruning caused the plants to spread vegetatively–and by spreading the fruit seeds in their dung.  Passenger pigeon flocks had the same effect.  When the incredibly enormous flocks of passenger pigeons roosted in one area, their dung would cover the ground, killing the trees through overfertilization, and opening the canopy to the benefit of plants such as gooseberry which became one of the first floral species to colonize a pigeon roosting area after the tree kill (pokeberry and ginseng are 2 other plants noted for growing in this type of environment).  Poultry manure also raises the ph level of the soil.  The Miccosukee gooseberry only grows on alkali “sinks.”  The pigeons were also known for berry consumption and were capable of spreading the seed far and wide due to their highly migratory habits (their scientific name is Ectopistes migratorius).

Miccosukee gooseberries have a low germination rate, probably contributing to their relict geographic range.  This species may have been more widespread during the Pleistocene when mastodons roamed the land.  Mastodons helped propagate this species in several ways.  Mastodons ate tree branches, thus allowing more light to reach the low growing gooseberries.  When mastodons ate the gooseberry bushes, it facilitated the growth of clonal colonies which spread via the root system.  The gooseberries may have had a higher germination rate after passing through a mastodon’s digestive tract.

Miccosukee Gooseberries may have also relied on passenger pigeons to spread their seed.  Passenger pigeons carrying gooseberry seed in their gut could spead the species far and wide.  It’s probably no coincidence that the last 2 populations of Miccosukee gooseberries are located in the kind of habitat where massive flocks of pigeons formerly roosted.  The manure from the massive flocks of roosting pigeons raised the ph level of the soil.  This type of gooseberry only grows on soils with a high ph.

Scientists attempting to ensure the survival of this species of gooseberry face some obstacles.  The Miccosukee gooseberry has a low germination rate.  This low germination rate supports my hypothesis that its decline coincides with the extinctions mentioned above.  It’s likely gooseberry seeds need to go through the digestive tract of a mastodon or pigeon to improve germination.  Efforts to transplant and propagate the Miccosukee gooseberry have been a complete failure.  This species has low genetic diversity, but there is a high degree of genetic divergence between the Florida and South Carolina populations, evidence they’ve been isolated from each other for quite some time.  The species wasn’t known to science until 1924, a generation after the extinction of the passenger pigeon.  There’s no telling what its range was during the 19th century.  The South Carolina colony wasn’t discovered until 1957.

The Steven’s Creek population grows under a canopy of oaks, hickories, and beech.  Gooseberries leaf out in November and lose their leaves in mid-summer, thereby taking advantage of the increased sunlight they experience when deciduous trees drop their leaves.  Bumblebees and blueberry bees pollinate the flowers.  One source claims the fruit is delectable but sour; another source says the fruit is of poor quality.  I suspect the latter source is closer to the truth, but I don’t know because I’ve never eaten this variety.

Unlike the Miccosukee gooseberry, the eastern prickly gooseberry is more widespread ranging from the midwest to the southern Appalachians.  Reportedly, they are fairly common on Grassy Mountain in the Cohutta Wilderness Area of north Georgia where they grow on boulderfields in the understory of a birch-maple forest.

The eastern prickly gooseberry (Ribes cynosbati) is common throughout the midwest and as far south as the southern Appalachians.  Reportedly, they are a frequent component of an interesting forest growing on Grassy Mountain within the remote Cohutta Wilderness Area of the Chattahoochee National Forest.  According to Jennifer Moore who wrote her college thesis about the forest on this mountain, the prickly gooseberry grows among the boulderfields on Grassy Mountain.  The name is a misnomer–it hasn’t been grassy for over 100 years since pastoralists abandoned the land, and trees began growing in the absence of livestock grazing and fire.  The boulders are the result of severe Pleistocene freeze and thaw cycles that broke up the rocky mountain surface.  A forest of mountain maple, yellow birch, tulip tree, basswood, and buckeye dominates over a shrub layer consisting of smooth hydrangea, strawberry bush, raspberry, prickly gooseberry, and marginal wood fern.  Windthrows are common here, aiding the growth of the shrubby zone.  Much of the mountain is inaccessible to non-hikers, making it a real destination for people seeking solitude with nature.  Better bring pepper spray–I bet there are lots of bears here.

I’ve never eaten a fresh gooseberry.  They aren’t cultivated in Georgia as far as I know.  I tried growing some a long time ago but the plants croaked in the merciless heat.  The canned ones taste like sweetened okra.  Even canned gooseberries are rare in Augusta–none of the local grocery stores currently carry them.

Here’s a related article on Pleistocene Passenger Pigeon Populations.

Pleistocene Passenger Pigeon Populations

August 27, 2010

(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.”


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.


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


Knopf 2005