Comparisons of song parameters, including syllable length and maximum and minimum frequency, from six populations of the Hutton's Vireo (Vireo huttoni) show differences in syllable length and minimum frequency measurements. Specifically, syllables produced by Pacific coastal birds tend to be shorter than those from southwest interior populations, although these differences are not statistically significant at the pairwise-comparison level. Syllables produced by most coastal populations have significantly higher mean minimum frequencies when compared with those from interior populations. Differences between songs of coastal and interior populations are consistent with genetic differences that separate the two groups. Differences in song may be attributed to the acoustical properties of coastal versus interior habitats.