Grasshopper sparrow males sing two song types that differ structurally and functionally. While the primary territorial song (the “buzz song”) has a relatively stereotyped structure across individuals and populations, the secondary song (the “warble song”) is more variable. Songs that contain multiple, repeated elements such as the warble song can differ both phonologically and syntactically between individuals, populations, and subspecies. We visually inspected warble song spectrograms to create a library of syllable types that we will eventually apply to populations across several subspecies of this bird in North America and the Caribbean. We grouped syllables based on acoustic features such as the start and end frequencies, number of frequency modulations, total bandwidth, and duration. We successfully implemented a classification scheme for these syllables in populations from several subspecies. We have found that while individuals over a broad geographic range share syllable types, each individual has a unique warble song due to differences in positioning or repetition of these similar elements. This is the first attempt to quantify the structure and possible syntax of the warble song, and it may reveal interesting new distinctions between the songs of different subspecies.