Definition
The passenger pigeon (*Ectopistes migratorius*) was a North American bird that went extinct in the early 20th century. Once, it was the most abundant bird in North America, with flocks so large they darkened the sky for hours. Imagine seeing billions of birds flying overhead! Overhunting and habitat destruction led to its rapid decline and eventual extinction. The passenger pigeon's story is a stark reminder of how human actions can devastate even the most numerous species. It is a classic example used in conservation education.