What Can the Passenger Pigeon's Extinction Teach California?
This year marks the 100th anniversary of the death of the last passenger pigeon, and though the actual anniversary doesn't come until September the event is already getting some attention in the media.
No wonder: the story of the passenger pigeon's end is a compelling cautionary tale about our impact on the wild world.
And though the birds weren't native to California during historic times, the passenger pigeon's extinction has a California parallel, a similar story of destruction and end that played out at more or less the same time.
At 1:00 p.m. on September 1, 1914, Martha, the last known individual of the species Ectopistes migratorius, was found dead in her cage at the Cincinnati Zoo. She was an "endling," the last of her species, but her kind had been functionally extinct for some years. Martha had been preceded in death by two male companions at the zoo, the last of which had died four years previous.
Since about 1890, scientists had attempted to coax the planet's remaining passenger pigeons to breed in captivity, to no avail. By the time the species was down to Martha and her two boyfriends in 1907, they were getting on in years, likely beyond their ability to breed even if they'd wanted to. The last remaining male died in July 1910, and Martha held on for four more years, the last living remnant of a species that once dominated eastern North America.
Martha's death made it official, but in an ecological sense the passenger pigeon had already been extinct for many years. In decline for decades, the species' numbers started to free-fall in the early 1870s. By the mid-1880s in the heart of the birds' former range, they were already becoming rare.
It's not hard to imagine why the birds are no more. Individual hunters could shoot thousands of birds a day, and the pigeons were thus an easily obtainable source of food for the poor, for livestock, and -- in certain states -- for slaves. The pigeons depended on intact hardwood forests for food, shelter, and breeding habitat, and those forests were largely cut over, burned down and rooted out by the late 19th Century. It's a wonder the birds held out as long as they did.
The notion that passenger pigeons would become rare had apparently been unthinkable just a few years earlier. In the early 19th Century, there were more passenger pigeons in North American than there were people. That comparison only hints at the pigeons' abundance. Flocks so thick that they obscured the sky took days to pass overhead as they migrated. The birds settled by the hundreds of millions in breeding colonies covering hundreds of square miles, with as many as a dozen nests in every suitable tree.
The birds themselves were good-sized, about the same size as the imported European pigeons that frequent our cities, though the Passenger Pigeons resembled mourning doves more closely. At their peak, their numbers were estimated at between three to five billion, potentially making up about 40 percent of the total bird population in North America.
It's possible that the pigeons' spectacular abundance was a bit of an anomaly, a result of the plagues that swept across the continent in advance of European colonization. Though the birds were almost ridiculously easy to capture, archaeologists don't find too many pigeons in native refuse dumps from before 1492.
That suggests that the birds may have been rare at one point. The pigeons would have directly competed with Native people for the wild and cultivated food both relished: the acorns and American chestnuts, the agricultural crops. Some scholars suggest that the plagues that killed off tens of millions of Native people in the 16th and 17th centuries sent the eastern forest ecosystems into a tailspin, with an explosion in pigeon numbers as one result.Regardless, in 1857, the immense abundance of the birds seemed to some to be an immutable fact of nature. When early conservationists noting a gradual decline in the birds sought to have Ohio's Legislature enact protections for the pigeons, a Senate Committee responded in language that has since gone down in history as legendarily wrong:
The passenger pigeon needs no protection. Wonderfully prolific, having the vast forests of the North as its breeding grounds, traveling hundreds of miles in search of food, it is here today and elsewhere tomorrow, and no ordinary destruction can lessen them, or be missed from the myriads that are yearly produced.
Ninety years later, the revered wildlife biologist Aldo Leopold spoke of the pigeons in the increasingly distant past tense while dedicating a memorial to the species in Wyalusing, Wisconsin:
Men still live who, in their youth, remember pigeons. Trees still live who, in their youth, were shaken by a living wind. But a decade hence only the oldest oaks will remember, and at long last only the hills will know.
Passenger pigeons lived in a very different California during the Pleistocene, according to the fossil record. By the time French naval officer and explorer Jean-François de Galaup, comte de Lapérouse visited California in 1786, the birds were long gone from the Far West, restricted to North America east of the Rockies. But the skies Lapérouse saw in the San Francisco Bay Area, above Monterey, and along the cliffs and estuaries of the Mendocino Coast were no less awe-inspiring for lacking passenger pigeons.
Lapérouse's journal provides one of the first glimpses of what California looked like in the days before American conquest. He is widely quoted as referring to the Californian landscape as being of "inexpressible fertility," in the sense of supporting huge populations of wild animals. The truth is that he actually used the phrase in a discussion of soil in mission crop fields near Monterey.
But the phrase is apt enough to describe California's wild landscape as the first Europeans arrived. Waterfowl darkened the skies above the coast's grassy wetlands. Whales beached themselves to feed the Coast Range grizzlies and condors. Herds of elk and pronghorn wandered the interior valleys, the largest of which -- the Central Valley -- was described by John Muir in the late 19th Century as an endless garden of wildflowers.
The relatively low topography of eastern North America offered the passenger pigeon perhaps two million square miles of uninterrupted potential habitat, enough to support those unimaginably large flocks. A billion birds could settle in an area the size of a county, eat everything that wasn't tied down, and be on the move, leaving only a two-inch layer of dung and shed feathers behind. California's landscape is big, but not that big. There were no marauding armies of a billion pigeons here. There were just assemblages of hundreds of thousands of geese, of sandhill cranes, of the state's multifarious species of ducks and shorebirds. There were just rivers that every few months would turn red with the thrashing of salmon, the usual description being that you could walk across the river on their backs, and locals pitchforked them out of the rivers by the cartload to feed their hogs.
And now? The California condor teeters on the edge of an expensive extinction. Tule elk and pronghorn persist only after immense effort. The Central Valley's chain of fertile wetlands has been choked down to a few starved refuges in a sea of cotton fields. In ten years, we will note the centenary of the passing of the last California grizzly.
In California's 165 years of statehood we have washed mountain slopes out to sea, dried out the largest freshwater lake west of the Mississippi, and cut down what had been some of the oldest forests on Earth for redwood lumber.
We ate the passenger pigeon and destroyed its habitat, and then, having learned some things about efficiency, we came to California and ate the habitat. A hundred years after the last passenger pigeon died, that is Martha's lesson for those of us who still live in the California landscape. Leopold's "oldest oaks" fall victim to one more strip mall, and the hills struggle to remember as we scrape them down to make it easier to pave them.
