The passenger pigeon or wild pigeon (Ectopistes migratorius) is an extinct North American bird. Named after the French word passager for "passing by", it was once the most abundant bird in North America, and possibly the world. It accounted for more than a quarter of all birds in North America. The species lived in enormous migratory flocks until the early 20th century, when hunting and habitat destruction led to its demise. One flock in 1866 in southern Ontario was described as being 1 mi (1.5 km) wide and 300 mi (500 km) long, took 14 hours to pass, and held in excess of 3.5 billion birds. That...