Birdsong's primary function is attracting and stimulating mates and repelling rivals during the breeding season. However, many species also sing during the nonbreeding season, which raises questions about the function of nonbreeding season song and the mechanisms underlying its production. In this study, we compared spectral and temporal measurements from a large sample of breeding (N = 267) and nonbreeding season songs (N = 283) of the Carolina Wren (Thryothorus ludovicianus), a nonmigratory, temperate species that sings year round. We found that breeding season songs were longer than nonbreeding season songs and had more syllables within each song. Trill rate, the number of notes per syllable, minimum and maximum frequency, and frequency bandwidth did not differ detectably between the 2 seasons. This study is the first to examine seasonal song differences in Carolina Wrens and provides a basis for future investigations into the drivers behind this seasonal variation.