Passenger Pigeons: And then there were none
June 19, 2012
Flocks of passenger pigeons once streamed from horizon to horizon above our hills. But they were driven to extinction in less than one human lifespan.
Early one May morning in the mid-19th century, W.R. King’s servant shook him awake at Fort Mississauga near Niagara-on-the-Lake to witness a spectacle:
“Hurrying out and ascending the grassy ramparts, I was perfectly amazed to behold the air filled and the sun obscured by millions of [passenger] pigeons, not hovering about, but darting onwards in a straight line with arrowy flight, in a vast mass a mile or more in breadth, and stretching before and behind as far as the eye could reach.
“Swiftly and steadily the column passed over with a rushing sound, and for hours continued in undiminished myriads advancing over the American forests in the eastern horizon, as the myriads that had passed were lost in the western sky.”
In 1914, little more than half a century after King’s account of the sky-filling multitude, a lone passenger pigeon named Martha slumped off her roost in the Cincinnati zoo. Her death marked the official extinction of her kind. Martha was the last of a population once numbered in the billions.
I find few stories more poignant than the tragic history of the passenger pigeon. From a scientific perspective, I’m fascinated that a species could decline to oblivion in such a short time. From a conservation perspective, I am humbled by the short-sighted human activity that perpetrated such an ecological atrocity.
King’s account of the tremendous mile-wide, 14-hour passage appeared in his 1866 book The Sportsman and Naturalist in Canada. In 1955, in his definitive book The Passenger Pigeon, A. W. Schorger made calculations – based on King’s extended description of the speed, density and length of the flock he witnessed – to determine it may well have comprised more than three and a half billion birds. Other pioneers, naturalists and explorers (among them, Samuel de Champlain and J. J. Audubon) described flocks as “roaring past like a tornado,” in “countless numbers” with “neither beginning nor end, length or breadth of these millions and millions.”
It’s almost impossible to imagine a congregation of more than three billion creatures. There are accounts of huge swarms of locusts numbering in the billions, but as far I can tell, the flock of passenger pigeons King witnessed represents the largest massing of a single animal species ever recorded – and it was right here in Ontario.
Estimates of the historic population of passenger pigeons vary from around three billion to as high as nine billion. According to Partners in Flight (a co-operative organization of governments, scientists and conservation groups), the robin is currently the most abundant bird in North America, with an estimated population of 310 million or, at most, 10 per cent of the former population of passenger pigeons. The current total North American bird population is around five billion. So, at one time there were likely more passenger pigeons than there are all birds in North America today.
Nevertheless, a scant six decades after King’s book was published, passenger pigeons had been reduced to small vagrant flocks. The last reliable sightings in Ontario occurred around the turn of the century, including a record of ten from around Orangeville in 1899. Only a year later, in 1900, the last wild passenger pigeon died when a young boy in Pike’s County, Ohio, shot it with his BB gun. And when the captive Martha died in Cincinnati, the species, once among the most abundant ever, vanished.
In their heyday, passenger pigeons ranged widely over much of eastern North America, but the heart of their territory was relatively small, defined by the presence of mast-producing hardwood trees such as beech, oak and chestnut. They occurred in abundance from around Kentucky in the south to Algonquin Park in the north.
At one time there were likely more passenger pigeons
than there are all birds in North America today.
I have often wondered if the young limbs of the now old trees on our little patch of land just south of Erin were once bent with the weight of pigeon flocks. So I have, on and off, searched for evidence of their presence in our neck of the woods, looking through archives, old newspapers and historic literature.
I found the best information on local occurrences in a 1935 publication commissioned by the Royal Ontario Museum to capture the recollections of those who could still remember the birds in Ontario. That publication and another one by the Canadian Field Naturalists note a sizable colony near Guelph in 1855, at a place called Hatch’s Swamp. There is a record of “an immense flock flying over the mountain,” likely the Niagara Escarpment, in the Trafalgar area in 1857 or 1858. (Trafalgar was the historic name for the Oakville-Burlington area.) The last large flight recorded in southern Ontario seems to have been of a flock “flying west ceaselessly for two and a half days” in the Dufferin/Mono area around 1870.
Although I found no references specifically to Erin (not even to the village’s former names of Erinsville and McMillan’s Mill), records from our general area are common. In the latter years, small flocks or individual birds were recorded in Dufferin, Orangeville, Luther and Camilla, as well as in Toronto (which seems to have been on a major migratory path), Guelph, York, Campbellville, Halton and Burlington.
The culmination of my research was a trip to the ROM. There, Mark Peck, a technician in the natural history department, showed me the museum’s collection of passenger pigeon “skins.” It is the largest collection in the world, thanks to the remarkable efforts of a former curator, Paul Hahn, who tracked down the remains of over 1,500 birds, acquiring a good number of them. Some were in excellent condition, a tribute to the care of the taxidermists; others were rather shabby, reflecting their age. Most were from the mid- to late 1800s.
What a surreal experience it was to see those taxidermied remains of dozens of animals – the ignominy of extinction spread out on museum trays. I felt awed (and odd) in the presence of these extinct animals. While Mark’s demeanour was more matter-of-fact, it was clear he too felt more than a twinge of something special, reverence perhaps, in the presence of these “specimens.”
So how did passenger pigeons go from overwhelming numbers to extinction over the course of a few decades? Some early, fanciful theories were proposed, including mass drowning in the Gulf of Mexico, but the most rational explanations point the finger at two main causes: overhunting and habitat destruction.
Stories of massive slaughters of passenger pigeons are common. In their nesting colonies pigeons were, well, sitting ducks. Professional “pigeoners” and others anxious to stock their larders used techniques such as poisoning the birds by burning sulphur, cutting down trees that contained scores of nests, or erecting large nets and other traps. When the massive flocks flew low overhead, as they commonly did, scores could be had simply by waving a long pole, killing birds that flew into it.
Of course, the preferred weapon was the gun. In an 1832 publication called A Backwoodsman, Dr. Wm. Dunlop describes a pigeon migration over Toronto (then York):
“Some two summers ago, a stream of [pigeons] took it into their heads to fly over York; and for three or four days the town resounded with one continuous roll of firing, as if a skirmish were going on in the streets – every gun, pistol, musket, blunderbuss and fire-arm of whatever description, was put in requisition … pigeons, flying within easy shot, were a temptation too strong for human virtue to withstand.”
Prior to the mid-19th century, commerce associated with pigeons was mostly local, in the area of the nesting colonies and roosts. However, by the 1850s, the burgeoning railway networks in the eastern United States facilitated the development of widespread markets. At peak activity, there were an estimated 5,000 professional pigeoners in the U.S. From one large nesting site in southern Michigan in the late 1860s, three boxcars of pigeons were shipped daily during a 40-day hunt. Although I found no records of extensive commerce in Ontario, pigeons were apparently sold regularly at St. Lawrence Market in Toronto.
It would be nice to think there was something
to learn from the fate of the passenger pigeon.
Most obviously, it is that abundance, even
superabundance, is no guarantee of survival.
The last great nesting of pigeons occurred near the town of Petoskey in northern Michigan. In 1878, a reported 50,000 birds were killed each day there for nearly five months. Here and elsewhere through their brief history of encounters with humankind, pigeons were hounded so incessantly at their nesting colonies that attempts to produce young often failed. By the late 1880s, wild pigeons were a very rare sight.
At the same time as pigeons were being killed wherever they sought to nest or roost, forests were being cleared over large areas, reducing habitat and forcing flocks into fewer expanses of woods, where they became even more available to hunters. The synergy between slaughter and forest clearing proved more than the birds could withstand.
Some aspects of the pigeons’ ecology also seem to have heightened their vulnerability. One blog I read referred to passenger pigeons as “blithering idiots, evolutionarily speaking.” Their tendency to live in large flocks may have been a strategy to swamp their natural enemies by sheer numbers. And that strategy worked for millennia, until man came along with his poison, nets and guns. With so much pressure over such a short period, the pigeons had no time to adapt – so not necessarily blithering idiots, but ill-equipped to deal with the sudden new pressures.
Furthermore, in spite of their tremendous numbers, pigeons were not highly productive. Each nest typically contained only one egg. However, they did raise two or three broods a year, migrating between broods from one bumper crop of mast to another. To find those crops, pigeons seemed dependent on a mechanism referred to as “social facilitation,” whereby the large flocks provided many individuals to search for concentrations of food. As the flocks decreased, social facilitation became less viable.
With their evolutionary disposition for living in large social groups, it’s believed that as population dwindled, isolated birds or small flocks may have experienced difficulties in feeding. Even in areas where there was still plenty of food, they may have died of starvation because of the stress caused by isolation.
And so passenger pigeons flickered out of existence, victims not only of man’s avarice, but perhaps because the evolutionary characteristics that allowed them to become among the most abundant of all living things also made them vulnerable to extinction.
It would be nice to think there was something to learn from the fate of the passenger pigeon. Most obviously, it is that abundance, even superabundance, is no guarantee of survival. Sadly, this is a lesson with lots of examples. The American bison once teemed across the prairies in the tens, even hundreds of millions and barely escaped extinction. Several populations of Atlantic cod, once so abundant it was said a person could walk on their backs in the ocean, are now classified as endangered.
I do believe the lesson of the passenger pigeon and other ill-fated species has contributed to the development of a strong wildlife conservation ethic in North America. Unfortunately, the path to this (relatively) more enlightened state was expensive indeed.
It is human instinct perhaps to want to fix history, to make good on past misdeeds, so while I was at the museum, I couldn’t help asking Mark Peck’s colleague, Oliver Haddrath, a geneticist in the ornithology department, if pigeons could be cloned from the collected remains. While not discounting the possibility entirely, he explained it was highly unlikely, at least for now. However, he did hold out a ray of hope, noting genetic technology is evolving very rapidly and accomplishments unheard of even 20 years ago are now commonplace.
That slim hope is all I need to fantasize what it would be like to once again see clouds of innumerable birds making their way across Ontario’s horizon – maybe even over my little patch.