This work provides an initial characterization of song sharing among males in the Northern House Wren (Troglodytes aedon parkmanii). A sample of 21 different males was studied at two different locations across two breeding seasons in southern Alberta, Canada. In total, 35,067 songs were analyzed to assess patterns of song sharing among males within and between study sites and in returning males between years. Virtually all syllable types (n=27) were shared among males. However, they were used to create very large repertoires of mostly unique song types. Absolute levels of song sharing among males was low but song sharing was higher among neighbouring males and decreased with increasing distance between males and across study sites. These patterns are discussed as they relate to important issues in the process of song learning, in the functions of large song repertoires in mate attraction and territory defense, and in the potential formation of dialects in this species. / xi, 102 leaves ; 29 cm