This section is from "The American Cyclopaedia", by George Ripley And Charles A. Dana. Also available from Amazon: The New American Cyclopędia. 16 volumes complete..
Passenger Pigeon, Or Wild Pigeon (ectopistes migratoria, Swains.), a well known columbine species peculiar to North America, where it exists in immense numbers. The family characters are given under Pigeon; the generic characters are, a very small head, short bill, long wings, the first primary the longest, tarsi very short, and tail very long and wedge-shaped. The male is about 16 1/2 in. long, with an alar extent of 25 in.; the general color above is grayish blue, some of the wing coverts being marked with black spots; throat, fore neck, breast, and sides light brownish red, and the rest of the under parts white; lower hind neck with golden, green, and violet reflections; quills blackish, bordered with pale bluish, the larger coverts whitish at the tip; two middle tail feathers black, the others pale blue at the base, becoming white toward the end; the bill black, iris bright red, and feet carmine purple. The female is smaller, and of duller colors. Their rapid and long continued flight enables them to pass over, and their keen vision to survey, a vast extent of country, when migrating at irregular periods in search of the mast which constitutes their principal food; the flight is high or low according to the region; for an account of the rapidity of their flight, see Carrier Pigeon. After feeding they settle on the trees, and toward sunset depart for their roosting places, often hundreds of miles distant; they build in forests where the trees are high, without much reference to season, and in places where food is abundant and water not far off; the flesh is dark-colored, and highly esteemed; according to Audubon, they lay two eggs.
These birds are found throughout temperate North America to the high central plains. Their numbers are absolutely countless both in the roosting and breeding place. Wilson describes one of their breeding places in Kentucky extending 40 m. through the woods and several miles wide, every tree bearing nests wherever they could be placed; they appeared about April 10 and left with their young before May 25; they were killed in immense numbers by the people gathered from a wide extent of country. Wilson calculates the length of a column of these birds which passed over him at 240 m., and estimates the number of pigeons in it at more than 2,000,000,000.
Passenger Pigeon (Ectopistes migratoria).