The flight of the Passenger Pigeon: phylogenetics and biogeographic history of an extinct species.

The human-caused extinction of the Passenger Pigeon (Ectopistes migratorius) is one of the best known and documented of any bird. This event was particularly alarming because the Passenger Pigeon went from being one of the most numerous avian species in the world to extinct in a period of decades, when the last individual died in captivity in a Cincinnati Zoo in 1914. While a great deal of information exists on the likely direct and indirect causes of its demise, as well as information on life-history, the phylogenetic relationships of this species have been subject to considerable speculation. Here we use DNA sequences obtained from museum specimens to resolve the phylogenetic position of this species with respect to other pigeons and doves (Columbiformes). We show that the Passenger Pigeon is not related to the New World mourning doves (Zenaida) as many authors have suggested, but is the sister taxon of all other New World pigeons (Patagioenas). Biogeographic analysis suggests the Passenger Pigeon lineage may have colonized North America from Asia, and subsequently dispersed into South America, leading to a more extensive radiation of New World pigeons.