Today we remember Martha. One hundred five years ago, at 1pm on September 1, 1914, Martha passed away.

Who was Martha, and why is her passing important?

For several years, Martha had lived at the Cincinnati Zoo. The last four years, she lived alone. She was the very last of her extended family, the final child of a population that once numbered in the billions.

Martha was a passenger pigeon.

Passenger pigeons once dominated our American skies. We can only estimate their population at its peak, as somewhere between three and five billion.

Taking the lower number, one in four birds in America was a passenger pigeon.

The size of their flocks would be considered fake news today, were it not for fact-based observations from many points and many times.

In the 1830’s, John James Audubon once described a flock as being a mile wide and taking three days to pass overhead. Stand outside, look up, and imagine birds filling the sky for days. Such a flock would contain millions of birds, flying sixty miles an hour, or ninety feet a second.

Seventy years later, by 1900, none would be left alive in the wild.

By 1914, the last one, Martha, died in captivity.

How could this even be possible? How could a creature go from three billion to zero in under a hundred years?

Extinctions rarely have a single answer. As we try to understand this spectacular crash, we might ponder one of the paradoxes of nature: resilience and fragility.

When we see millions of birds darkening the skies, we feel confident we can point our guns to the heavens, pull the trigger, and so take a few thousand birds out of millions. After all, how could flocks of such magnitude be diminished through our actions? The huge flocks meant a population naturally resilient to our actions. And they meant food, too, for millions of Americans. The market for passenger pigeons leapt into existence. Flocks of this size would never disappear.

Except they did.

Market hunting surely contributed to this. But there were other factors as well. The passenger pigeon didn’t lay as many eggs as other pigeons, relying on its massive population to offset predator kills. Recent studies of its genetics and environment also suggest it was susceptible to wild population swings. It may have been what is known as an “outbreak” species, capable of population explosions in favorable conditions, as well as collapses when those conditions disappear.

The population, huge as it was, may have begun declining even as Americans moved into the middle of the country in the early 1800’s. Or, by displacing Native Americans (who competed with the pigeons for acorns, beechnuts and other tree mast), settlers may have actually helped the population increase briefly. But then two more things happened. First, we began clearing land, eliminating the pigeon’s food source. Second, we began hunting. First for our own families, but then for tables in restaurants in cities to the east. We shipped trainloads of the birds off to be consumed elsewhere.

That proved fatal. We literally hunted the bird to extinction. Because it was a marketable resource, dwindling numbers meant “Get what you can as fast as you can.” When the population shrank and shrank, we doubled down and doubled down on our hunting. We weren’t feeding ourselves, you see. We were feeding the market for pigeons. We didn’t care about the bird. We may instinctively have known that the market wouldn’t, couldn’t last, as birds became increasingly scarce. And when they went, so went the market.

In this way, a seemingly resilient population reveals its underlying fragility.

Why total extinction? Why not just massive reductions in population, to some hundreds of thousands, say? The birds had existed in these populations before. The answer lies in the pace of things, in the speed of change (in this case, settling, clearing trees, and market hunting) versus the speed of adaptability. In the past, pigeon populations would fluctuate according to similarly-paced fluctuations in food supply (the Ice Age a good example of this). But in the middle 1800’s, the birds couldn’t adapt to multiple rapid and significant challenges to their existence.

We point to adaptability as the great tool that nature uses, as species adapt to environmental changes. After all, we humans have adapted to many different environments.

Here’s the thing. Adaptation is the work of centuries. Genetic diversity evolves over time as well. When we come along, clearing the land, hunting, creating shopping malls and interstates, we create in generations what will take centuries of adaptation for the rest of the world. The world can’t catch up.

Thus, extinction. Three billion to zero. The demise of the passenger pigeon is sometimes called the poster child of extinction.

Here’s another number.

One million.

That’s the number of species — not populations which are a multiple, but species — facing extinction today.

Here’s another pair of numbers.

One hundred, or one thousand. Scientists aren’t certain, but these numbers represent the multiples of extinction, today versus more typical times. In other words, species are going extinct at a rate somewhere between 100 to 1000 times typical.

What does this mean? Well, if (some would say it’s a big IF) — if our world’s resilience stems in part from its biodiversity, we’re in a heap of trouble.

I liken the extinction of a species, and its impact on surrounding environment, to what the closing of a business means to a community. If it’s an obscure species, maybe it’s like closing a barber shop — a few dozen customers, maybe a couple of missed lunches at the local diner. If it’s high on the food chain or otherwise significant, maybe it’s like closing a manufacturing plant — thousands of jobs, plus area diners, barber shops, supplier warehouses and plants, and so on. Loss of a manufacturing plant can close a town. Loss of several can depress an entire region.

If you close a million businesses, small and large, around the world, I suspect you’re asking for problems. If you closed businesses at a rate one hundred or one thousand times normal, we might pay attention.

Not so with extinction. If the Barrier Reef becomes completely barren, who will notice? If we can no longer eat Atlantic cod, will we simply switch to mackerel? If bee populations crash and pollination suffers, will we suffer, too? Or will these be insignificant distractions in a world full of interruptions? Do they matter? Should they?

Another thing about population. Consider three billion birds. That brings its own problems. Populations that grow out of bounds warp the natural distribution of plants and animals. At their peak, passenger pigeons caused whole groves of trees to crack and break under their weight. Not to mention the fact that they’d clean entire acres of forest mast, leaving behind incredible hillsides of excrement. Unsustainable and self-destructive behavior, even if humans hadn’t come along.

Through sheer numbers and feeding, the passenger pigeon sowed the seeds of its own starvation. Once those trees were gone, the pigeons would go, too. Though probably not all of them.

So while there’s tragedy in the passenger pigeon extinction, there’s some relief, too, as the earth shakes off their scourge and plant and animal populations rebound. I’d have settled for a few million birds. Nature is not always so forgiving. Once forces are unleashed, they can be unstoppable.

Here’s what we don’t know. We don’t know at what point in the decline the passenger pigeon population stepped off the metaphorical cliff and into a free fall to extinction. When did it cross the event horizon and get pulled inexorably into the black hole?

We don’t know.

Here’s another couple of numbers. Three quadrillion, and one hundred ninety-one.

Three quadrillion qualifies as a really big number. Unlike the smaller number, it’s an estimate, and it fluctuates. It’s the number of gallons of water in Lake Superior, a lake so large Maine could fit in its borders and so deep that if it were emptied, it would fill the surface of both North and South America to a depth of one foot. It contains approximately 10% of the world’s unfrozen fresh surface water.

The second number, one hundred ninety-one, is related to the first. It’s the number of years, on average, that a drop of water remains in Lake Superior. One hundred ninety-one years ago, Michigan (where I reside) wasn’t yet a state. In the twenty-four then-existing United States, there was no electricity, no cars, no airplanes, space travel, smart phones, satellites, dishwashers, radios, social media (at least as we understand it), baseball, basketball, hockey, American football, hotdogs or doughnuts. We’d yet to fight a Civil War, participate in two World Wars, ignite or get drawn into a whole bunch of undeclared wars, and generally grow incredibly large and influential. One hundred ninety-one years ago, pigeons numbered in the billions, while the global human population finally neared one billion.

Then the passenger pigeon went from billions to zero, while the worldwide human population doubled. In less than half the retention time of Superior’s water.

If change seems rapid to us, what is its impact on cycles that take centuries?

Why bring this all up, this business of Lake Superior and passenger pigeons? Because Lake Superior, like so many things, appears indestructible due to its size. As does, some would say, the Amazon rain forest, exposed for decades to land-clearing fires. As did, until recently, the ice of Greenland.

We — now seven or eight billion of us, a quadrupling over the previous century’s growth — are influential in the world in disproportionate ways, the same way the US is influential in geopolitical and economic affairs in disproportionate ways.

We think things will go on forever, and that it’s necessary and beneficial to exploit, and drill, and dig, and burn, and pollute, and consume, piling up things and trash. When scientists express concerns about the impacts of climate change or pollution, we declare fake news or non-science, calling these folks chicken little, or worse.

And when it dawns on us that burning down large parts of the Amazon rain forest might cause it to go through a passenger-pigeon crossover point, beyond which it becomes a savannah and shifts the oxygen-carbon balance of the planet — when it dawns on us that this might happen, there are those who would double down, and double down again. There are those who would burn more, buy Greenland, leave climate accords because they’re some kind of “bad deal,” and double down again on fossil fuels. Fuels we’ve been using in large quantities for less than one Superior retention cycle.

Changes, I would argue, that overwhelm nature’s resilience because they far outrun nature’s rate of adaptation.

Do we have to wait for a tipping point before we act, knowing then that it’s too late? If we can’t know the passenger pigeon’s tipping point, how can we assert that we know the last Amazon tree we can afford to burn? Why do we resist, when both our logic and our instinct point to hedging our bets, doing all we can to preserve rain forests and ice and species and climate bands that support human habitability? Why not take a variation of Pascal’s Wager, and assume climate change is real and therefore take protective action, instead of presuming it’s not real and doing nothing? What’s the cost of being wrong in either case?

Perhaps our instinct favors our own extinction.

Is it today’s problem? Maybe. Tomorrow’s? Our children’s children’s problem? I don’t know. But a problem nonetheless. And possibly — possibly soon — possibly already — a fatal and unsolvable problem.

I could fill a landfill with all the cans we’ve kicked down the road in the name of today’s fame, today’s wealthy lifestyle, tomorrow’s election results.

Nature won’t care about our election results. It won’t care if we remove scenic mountain tops and all their flora and fauna by declaring them overburden, by burning rainforests and protecting oil with military engines that themselves consume far more than the populations whose consumptive lifestyle they’re pledged to protect.

At some point, we pass through these tipping points, of oxygenation and ice and temperature and world diversity, and as we do so, like passenger pigeons stripped of their acorns we may well find ourselves short of food, short of water, short of breath, and short of life.

And nature won’t care if we die.

It will adjust.

Perhaps, evoking Jonathan Schell’s Fate of the Earth, the world will become a republic of insects and grass. And be relieved that a big, awkward, heavy-headed primate that once numbered in the billions, savaging the environment and leaving its waste everywhere, has been eliminated.

Perhaps the last of us, like Martha, will stare at a world that stares indifferently back, a world that no longer tolerates us, that gives us no food, no reasonable temperature, and no option for survival. Would we be like Martha at last?


The difference would be that we would know.