An extinct migratory bird (Ectopistes migratorius) abundant in eastern North America until the latter part of the 19th century. Extinct species (Ectopistes migratorius) of pigeon (subfamily Columbinae, family Columbidae). Passenger pigeons were about 13 in. (32 cm) long and had a long pointed tail; the male was pinkish, with a blue-gray head. Billions inhabited eastern North America in the early 19th century; migrating flocks darkened the skies for days at a time. Gunners began to slaughter them in huge numbers for shipping by railway carloads for sale in city meat markets. Martha, the last known passenger pigeon, died in 1914 in the Cincinnati Zoo. The bird's extinction was largely responsible for ending the marketing of game birds and gave major impetus to the conservation movement