The great American naturalist John James Audubon is best known for his beautiful drawings of birds, collected in The Birds of America (1827-1838). The five-volume Ornithological Biography, a companion to the collection of drawings, was published in 1831 and includes this essay on the now-extinct passenger pigeon. In it, Audubon describes the bird's remarkable power of flight, power of vision, and hard-to-believe abundance. As he writes of a flock...