The painting at right is a depiction of an underwater scene that could have occurred many thousands of years ago. Nine-foot-long sabertooth salmon swim beside two birds known as Chendytes lawi. I had not heard of the species until I received a notice the other day about a new paper examining its extinction. It turns out that the bird has quite a story.
It was a flightless seaduck that lived along the coast of California and Oregon. Its fossils are some of the most common birds found on the Channel Islands, suggesting that it nested there. It also likely used southern California's islets and offshore rocks for breeding colonies. Anthropologist Terry L. Jones of California Polytechnic State University and his colleagues report in a paper published in the Proceedings of the National Academy of Sciences that the bird's extinction occurred 2,400-2,200 years ago.
Previously, it was known to have lived until at least 3,780 years ago. For decades, Native American archaeological sites have produced bones of C. lawi, so it has been clear that prehistoric people hunted the birds. But the new study, in addition to adding more than 1,300 years to C. lawi's existence, proves that overhunting drove its extinction.
In fact, says Jones, humans hunted the seaducks for more than 8,000 years. The exploitation began about the time of the earliest known settlements of the Channel Islands — approximately 11,500 years ago. It continued on the islands and the mainland for several millenia.
"There is nothing," writes Jones, "in the North American archaeological record indicating a span of exploitation for any megafaunal genera remotely as long as that of Chendytes."
Flightless island birds tended to go extinct quickly after human contact — most infamously, the Dodo. It was gone a little more than a century after sailors landed on Mauritius in 1581. But a bird that lived on a continent or its shores could survive much longer, as Chendytes demonstrates.
Jones argues that the duck's prolonged existence disproves a theory that says Native Americans drove 35 species of megafauna (such as mammoths, camels, and giant sloths) to extinction in "a blitzkrieg fashion" approximately 13,000 years ago.
But what surprised me most in researching the bird is how utterly forgotten it is. Most ornithology textbooks don't refer to it, and studies of extinct birds concentrate on the last 500 years. (Admittedly, they have a lot of material to cover.) Yes, its extinction occurred a long time ago, but in evolutionary time, 2,400 years is little more than the blink of an eye.
The scientists who have studied C. lawi have learned a lot. It was first described as a diving goose in 1925 by Loye Miller, who was later called "the father of avian paleontology in California." Indeed, it was as big as a Canada Goose. Later investigators called it "scoter-like," although it was much larger than our modern scoters. In 1955, it was found to have had a smaller ancestor, C. milleri, that could fly.
In a 1993 paper, Bradley C. Livezey, curator of birds at the Carnegie Museum of Natural History, classified the bird with the eiders and other diving seaducks of the tribe Mergini. He noted that it "exceeded the largest extant seaduck, the Common Eider," and that its bill was "strikingly eider-like." Its flightlessness, he wrote, improved its diving capabilities, constrained its ability to move long distances, increased its dependence on easily accessible nest sites, and substantially limited its ability to migrate.
Being flightless made Chendytes unusual, to say the least. Only about 40 of the nearly 10,000 living bird species cannot fly. They include the penguins, kiwis, Ostrich, several rails, and five waterfowl: the Magellanic, White-headed, and Falkland Steamerducks of southern South America, and the Auckland Island and Campbell Island Teal of New Zealand.
Why the steamerducks and teal survive and North America's flightless duck didn't is a difficult question to answer. Habitat, population numbers, and frequency of human hunting all likely played a role. But Jones notes that Chendytes offers a lesson about sustainability.
"The history of humans trying to feed themselves and impacting the environment goes back further than a lot of people realize," he says.
Livezey, in his 1993 paper, put it this way: "Chendytes may represent the earliest known example from North America of the catastrophic impact of humans on flightless birds." — M.M.