The now-extinct passenger pigeon (Ectopistes migratorius), also known as the wild pigeon, wood pigeon and blue pigeon, was once the most abundant bird in North America, possibly the world. When Europeans first arrived here, as many as 5 billion of the dove-like birds were traveling across the continent, east of the Rocky Mountains, in massive flocks. The core breeding range of the species ran from southern Ontario and the Great Lakes south through southern Pennsylvania.
The most commonly used name, passenger pigeon, comes from the French word passager, which can be translated into "wandering about" in reference to the species" unrelenting, food-driven habits of mass and far-ranging migration.
It looked a lot like an over-sized mourning dove. The plumage was similar, but mature male passenger pigeons were 15-16 inches long and mature females were just a tad smaller. Much of the length was in the tail, which was 7-8 inches long. The adult birds weighed about 12 ounces. Adult males had a blue-gray head and neck, with areas of iridescent green to violet on the sides of the neck, black-spotted blue-gray back, rump and upper wings, gray-brown lower wings, white-edged black and brown primaries, pink throat and breast growing paler farther along the belly, and blue-gray tail feathers with white outer edges. Adult females were similar to the males, but with browner, paler undersides, primaries edged in pink or buff, less iridescence on the neck, buff-gray throat and breast, and white belly. Juveniles were similar to adult females, but darker.
The passenger pigeon produced a call that consisted of two "keck" sounds with a pause between them, a "kee-kee-kee" call, a long drawn-out "keeeeeeeeeeeeeee" and a soft cooing "keeeeeooooo."
It was a member of the pigeon and dove family, Columbidae, originally thought to be most closely related to the doves of the genus Zenaida, particularly the mourning dove. However, recent genetic analysis has shown that the passenger pigeon is most closely related to members of the genus Patagioena, with species like the band-tailed pigeon of western North America.
The passenger pigeon was a very social bird, spending a great deal of time roosting with others of its kind - often packed so tight together that their collective weight broke the branch they were perched on - and living in colonies the covered hundreds of square miles. It was highly migratory, moving great distances, primarily driven by food. Beechnuts, acorns and chestnuts were the primary food in fall through spring; berries, grapes and tree fruit saw the bird through summer. Cultivated grains also were on the menu. Worms, caterpillars, snails and slugs were eaten, particularly during the breeding period. And, salt was a prized edible for the birds, which found it in natural salt licks and springs.
When foraging for nuts, flocks of thousands of passenger pigeon frantically pushed their way through leaf litter, soil and snow, overturning everything in their path. Birds in the back of the group regularly flew up and over those ahead of them to become the new front of the flock.
Nesting colonies of millions of birds, even hundreds of millions, formed in late March, April or May. Eventually every tree in the considerable mileage occupied by the colony would hold nests, regularly more than 50 per tree.
Males courted females with various displays and movements. After a pair-bond was formed, the female built the six-inch-diameter twig-nest, with the male bringing her the materials, from 10-70 feet off the ground.
Each female laid one egg, typically in the first half of April. Incubation took 12-14 days and was the shared responsibility of the parents. Within two weeks of hatching the baby was nearly the size of the adults and in another three or four days fledged from the nests.