The extinction of the passenger pigeon is one of the best-known cautionary tales in American environmental history. At one time, between three and five billion passenger pigeons blanketed the skies over central and eastern North America. Passenger pigeons were swift (they could fly as fast as sixty miles per hour) and gregarious (in the winter, thousands would roost together on a single tree, occasionally causing limbs to break beneath their weight). They survived primarily on the beechnuts, acorns, and chestnuts found in the mixed hardwood forests of the eastern United States. Between 1810 and 1867, Americans destroyed much of that habitat, clearing 200,000 square miles of woodlands (an area equal to the size of Illinois, Michigan, Ohio, and Wisconsin combined). The passenger pigeon was also tasty, which is why between about 1870 and 1900, market hunters reduced what remained of the population to only a few dozen. The last of the species, named Martha by its keepers, died in the Cincinnati Zoo in 1914. Even more than the North American bison, a few hundred of whom survived the hide hunters who slaughtered millions of them in the Great Plains in the late nineteenth century, the passenger pigeon’s story exemplifies the wastefulness and shortsightedness of Americans’ exploitation of animals in the early years of industrial capitalism.