a stream of at least eight mixed notes that were both high and low in tone and ended with "keeho". Overall, female passenger pigeons were quieter and called infrequently. Craig suggested that the loud, strident voice and "degenerated" musicality was the result of living in populous colonies where only the loudest sounds could be heard. Distribution and habitat The passenger pigeon was found across most of North America east of the Rocky Mountains, from the Great Plains to the Atlantic coast in the east, to the south of Canada in the north, and the north of Mississippi in the southern United States, coinciding with its primary habitat, the eastern deciduous forests. Within this range, it constantly migrated in search of food and shelter. It is unclear if the birds favored particular trees and terrain, but they were possibly not restricted to one type, as long as their numbers could be supported. It originally bred from the southern parts of eastern and central Canada south to eastern Kansas, Oklahoma, Mississippi, and Georgia in the United States, but the primary breeding range was in southern Ontario and the Great Lakes states south through states north of the Appalachian Mountains. Though the western forests were ecologically similar to those in the east, these were occupied by band-tailed pigeons, which may have kept out the passenger pigeons through competitive exclusion. The passenger pigeon wintered from Arkansas, Tennessee, and North Carolina south to Texas, the Gulf Coast, and northern Florida, though flocks occasionally wintered as far north as southern Pennsylvania and Connecticut. It preferred to winter in large swamps, particularly those with alder trees; if swamps were not available, forested areas, particularly with pine trees, were favored roosting sites. There were also sightings of passenger pigeons outside of its normal range, including in several Western states, Bermuda, Cuba, and Mexico, particularly during severe winters. It has been suggested that some of these extralimital records may have been due to the paucity of observers rather than the actual extent of passenger pigeons; North America was then unsettled country, and the bird may have appeared anywhere on the continent except for the far west. There were also records of stragglers in Scotland, Ireland, and France, although these birds may have been escaped captives, or the records incorrect. More than 130 passenger pigeon fossils have been found scattered across 25 US states, including in the La Brea Tar