One hundred years ago today, on September 1, 1914, Martha, the last-known living Passenger Pigeon died at the Cincinnati Zoo. Her death, at 29 after a lifetime in captivity, marked the disappearance of her once-abundant species from the world.
Difficult as it is to comprehend, there was a time when the Passenger Pigeon (Ectopistes migratorius) was the most common bird in the United States, numbering in the billions. But victim to overhunting and habitat destruction, Passenger Pigeon populations began to decline in the second half of the 19th century and the species was considered extinct in the wild by the turn of the century.
Learn more about passenger pigeons, and about the sciene of de-extinction.