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When the first humans strode across the land bridge that once united today’s Russia and Alaska, they didn’t know they were entering a wild new world. It wasn’t until they crossed the enormous, mile-thick ice sheet that smothered the entirety of Canada that humans first met the wildlife that made America so distinctive.
When these Paleo-Indians reached what is now the continental United States around 16,000 years ago, they encountered a world much different than the one their ancestors left behind in Asia, and a world much different than the one we know today. It was one filled with ground sloths and short-faced bears, mastodons and giant beavers, saber-toothed cats, horses, bison, American oxen, American cheetahs, American horses, and American lions. They found a Serengeti worth of strange and remarkable mammals, some toothy, some meaty, some fast, some frightening, but all of them very, very big.
Their new world was also filled with birds. These proto-birders would have marveled at the brilliant warblers, skulking thrushes, and enormous flocks of ducks and shorebirds that American bird-lovers are familiar with today. But they were also met by dozens of birds that are now absent from the continent, birds that vanished with the mammoths and mastodons. Thousands of years before they lost the Passenger Pigeon and Carolina Parakeet, America’s inhabitants became familiar with avian extinction.
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Virtually everything we know about birds that disappeared before colonization comes from the fossil record. One of the best sources for understanding the world of America’s earliest birders is the La Brea tar pits, which lie in the middle of modern-day Los Angeles. For the last forty thousand years, sticky tar bubbling up from rocks has trapped animals large and small. When scavengers gathered to feast on their bodies, the tar trapped them too and embalmed their bones.
The pioneering paleontologist Hildegarde Howard completed the first census of La Brea’s birds in 1930, when she was just 28 years old. Howard identified 4,189 individual birds in her study, which gives us a vivid picture of the wildlife that California’s earliest birders would have seen.1
The first humans to visit La Brea would have seen at least twenty-eight species of birds that no longer inhabit our world. They could have watched at least six kinds of woodpeckers, of which three are now extinct. They might have heard the hoots of nine species of owls, three of which are also gone forever. Alongside Whooping Cranes and Sandhill Cranes, they would have seen Page’s Crane, a smaller bird with a longer, more slender bill. They would have admired Phoenicopterus minutus, a small species of flamingo, and heard the cackles of Euphagus magnirostris, the Large-billed Blackbird. They would even have witnessed massive flocks of Passenger Pigeons, whose range once reached California.
Sixty percent of the individual birds that Howard found at La Brea were falcons, hawks, vultures, condors, and an extinct group of enormous vulture-like birds called teratorns – all drawn to dead and dying animals trapped in the tar. The world that the earliest Americans first encountered was home to a much greater variety of these aerial scavengers, proportional in size and diversity to the enormous mammals they once ate. The ecological changes that took place after people arrived, most notably the extinction of most large mammals, were more devastating to this group of birds than to any other.
In addition to today’s Turkey Vulture, Black Vulture, and California Condor, La Brea’s first birders saw two other now-extinct vultures and at least one more species of condor. They would have seen Golden Eagles (the species most frequently represented in La Brea’s fossil beds) as well as extinct raptors like the Walking Eagle, with legs as long as a Great Blue Heron’s, and Woodward’s Eagle, an enormous hawk whose wingspan reached at least nine feet.
But undoubtedly, the Paleo-Indians would have been most astonished by the teratorns. While they scavenged carrion like their vulture cousins, these hulking giants also probably hunted small game which they swallowed whole. The one we know the most about is Merriam’s Teratorn, from the hundred-plus individuals found at La Brea, the most recent dating to 8,000 BC. Paleontologists estimate that they weighed at least thirty pounds and had a wingspan of about twelve feet, making them a third larger than the already-enormous California Condor.
Larger still was the Woodburn Teratorn, whose scarce remains from around 10,000 BC put its wingspan at fourteen feet, a foot and a half longer than any bird alive today. But even this bird was dwarfed by Aiolornis incredibilis. All that paleontologists have found of this bird are fragments of a beak, ulna, humorous, and radius, but these were enough to suggest that the bird weighed fifty pounds and had a breathtaking wingspan of eighteen feet. The fact that these birds overlapped with Paleo-Indians has led to some speculation that they were the origin of the widespread belief among North America’s indigenous peoples in the legendary thunderbird.
Of all of the condors that once ranged North America, the only one that survived (and even that, just barely) is the California Condor. Until the late-pleistocene extinctions, this bird’s range stretched from coast to coast, and like the teratorns, it disappeared from most of its range alongside the giant mammals it depended on for food. But it seems likely that the condor managed to survive along the Pacific coast by feeding on whales, seals, and other marine megafauna that washed up on shore.
After raptors, the most common bird found at La Brea was the California Turkey, a slightly smaller cousin of today’s Wild Turkey, which disappeared around 10,000 years ago. Unlike the teratorns, the California Turkey probably went extinct because early Californians really liked to eat them. But the picture is a little more complicated. Humans arrived shortly before a severe drought killed off the roost trees that turkeys depended on. This would have forced the birds to congregate around the few remaining water sources and made them easy targets for hunters.
The fact that humans arrived in North America right when melting glaciers and shifting rains dramatically altered the continent’s environment makes it hard to determine how much of a role they played in the wave of extinctions that followed. While hunting most likely played a huge role in wiping out large mammals like the California Tapir and Ancient Bison, the picture is more murky for animals like the Convex-billed Cowbird, Wetmore’s Stork, or Kurochkin’s Pygmy Owl. These birds probably would have survived just being hunted (if they were hunted at all), but they might have depended on large mammals or the ecosystems that these large mammals maintained in order to survive.
Whatever the exact cause – and it was likely different for each species – dozens of birds disappeared within just two or three thousand years of humans showing up. Each one quickly proved incompatible with the new world that these new humans ushered in.
But this makes the case of one last bird so much more interesting. While all the other pleistocene birds disappeared relatively quickly, the fossil record shows that people interacted with Law’s Diving Duck (chendytes lawi), a goose-sized, flightless sea duck that lived off the California coast, for more than ten thousand years. The bird’s bones and eggshells showed up near human settlements until sometime between 450 B.C. and 250 B.C. When they ultimately disappeared, likely from a combination of hunting, habitat loss, and climate change, it wasn’t just a species that was lost. The world also lost thousands of years of traditions and knowledge that had been built up around them. What names were they given? Did people wear their feathers, or keep the birds as pets? What stories about these birds were passed down from generation to generation? These are things we’ll never know.
The Pronghorn, an antelope-like speedster of America’s great plains, is the second-fastest land animal in the world. Maxing out at fifty-five miles per hour, they’re just barely beaten by the cheetah’s sixty-one. Pronghorns easily outrun any wolf or coyote that might wish to eat them today. But they didn’t evolve their speed to escape coyotes – they evolved to escape American cheetahs. Even though these cats disappeared 12,000 years ago, we can still see their ghosts echoing through the millennia in the now-obsolete bodies of the Pronghorn.
We don’t really know how America’s now-extinct birds shaped the continent, how they shaped the plants and animals that still remain. But we do know that they interacted with our familiar backyard birds for millions of years, and the results of these interactions are still written in their genes. America was home to Merriam’s Teratorns, California Turkeys, and Law’s Diving Duck for millions of years. They’ve only been gone for the last ten thousand. The world still hasn’t fully adapted to their absence.
The lost world of the dinosaurs, hundreds of millions of years gone, feels far enough away to study with emotional reserve. I don’t harbor any great sadness about never getting to meet a brontosaurus or archaeopteryx. Those beasts never shared the world with our kind; Pangea might as well have been an alien planet. But I can’t think about the birds we lost in the late pleistocene extinctions without feeling the same grief that Great Auks or Ivory-billed Woodpeckers inspire. On a geologic time scale, teratorns feel almost close enough to touch.
In one of his most famous passages, Henry David Thoreau captured this sadness best:
“When I consider that the nobler animal have been exterminated here – the cougar, the panther, lynx, wolverine, wolf, bear, moose, dear, the beaver, the turkey and so forth and so forth, I cannot but feel as if I lived in a tamed and, as it were, emasculated country… I take infinite pains to know all the phenomena of the spring, for instance, thinking that I have here the entire poem, and then, to my chagrin, I hear that it is but an imperfect copy that I possess and have read, that my ancestors have torn out many of the first leaves and grandest passages, and mutilated it in many places. I should not like to think that some demigod had come before me and picked out some of the best of the stars. I wish to know an entire heaven and an entire earth.”
As a final note, I’ve put together a full list of the 132 species of fossilized birds found at La Brea. Extinct birds are highlighted in red.
