Song Repertoire of Carolina Chickadees (Poecile carolinensis) in Southeastern Pennsylvania

Songs of the Carolina Chickadee (Poecile carolinensis) vary throughout the species' geographic range. The aim of this study was to investigate quantitatively the repertoires of individual Carolina Chickadees in southeastern Pennsylvania. Previous qualitative work in the same region identified two song types produced with different degrees of consistency. We recorded locally breeding males during 2 years to assess song types at the population level and to characterize repertoires of individuals. Most males included the same two common song types (A and B) in their repertoires; cluster analysis also identified a third song type (B′) resulting from deletion of an initial note. The amount of variation within the song types differed, with the more stereotyped A song produced more frequently (averaging 79% of songs by individual males) than the more variable B (21%) and B′ (