Some spectacular migrants have already gone extinct; during the Passenger Pigeon's ("Ectopistes migratorius") migration the enormous flocks were a mile (1.6 km) wide, darkening the sky and long, taking several days to pass.
Some spectacular migrants have already gone extinct, the most notable being the Passenger Pigeon ("Ectopistes migratorius"). During migration the enormous flocks were a mile (1.6 km) wide, darkening the sky and long, taking several days to pass.