Characteristics of birdsong, especially minimum frequency, have been shown to vary for some species between urban and rural populations and along urban-rural gradients. However, few urban-rural comparisons of song complexity—and none that we know of based on the number of distinct song types in repertoires—have occurred. Given the potential ability of song repertoire size to indicate bird condition, we primarily sought to determine if number of distinct song types displayed by Song Sparrows (Melospiza melodia) varied between an urban and a rural site. We determined song repertoire size of 24 individuals; 12 were at an urban (‘human-dominated’) site and 12 were at a rural (‘agricultural’) site. Then, we compared song repertoire size, note rate, and peak frequency between these sites. Song repertoire size and note rate did not vary between our human-dominated and agricultural sites. Peak frequency was greater at the agricultural site. Our finding that peak frequency was higher at the agricultural site compared to the human-dominated site, contrary to many previous findings pertaining to frequency shifts in songbirds, warrants further investigation. Results of our pilot study suggest that song complexity may be less affected by anthropogenic factors in Song Sparrows than are frequency characteristics. Additional study, however, will be required to identify particular causal factors related to the trends that we report and to replicate, ideally via multiple urban-rural pairings, so that broader generalization is possible.

The data reported herein were collected as described in the open access published article. Briefly overviewed: we recorded the vocalizations of Song Sparrows in an urban and in a rural environment. Then, we compared song type repertoire size, peak frequency, and note rate between the sites. We report these measures for each bird in the 'BrewerFudickar_SongData' csv file. The other three data files present 1) noise levels at both sites, 2) impervious surface coverage at both sites, and 3) song types recorded as a function of song instances recorded for a subset of birds.

We have presented all of the files required to reproduce the analysis and data figures presented in our study. There are four text files which present the metadata; one for each of the four data files. There are three .R files (BrewerFudickar_ImpervStats.R, BrewerFudickar_NoiseStats.R, and BrewerFudickar_SongStats.R) that present code used for the analyses. There are three .R files (BrewerFudickar_EffortCurves.R, BrewerFudickar_SongBoxPlots.R and BrewerFudickar_NoiseImpervFig.R) that present the code for making the data-based figures from our study. There are no missing data.