The acoustical repertoire of the eastern willet was recorded at sites along the Atlantic seaboard using a Marantz portable cassette recording deck (model PMD 221), a Sennheiser microphone (model K3-U), and a 62-cm fiberglass parabolic recording dish. Associated behaviors were annotated on audio tape and in field notebooks. Call parameters were measured using a DSP Sona-Graph model 5500. Variation in call parameters was assessed within individuals, within populations, between geographical regions, and between subspecies using cross correlations and univariate and multivariate statistical methods. Sonograms, preliminary quantitative results and aural comparisons suggest relatively little structural variation in calls across large geographical regions. One notable exception in this pattern was observed at the subspecific level, and a hypothesis is advanced linking differences in ecology and environmental features to explain this divergence. Some intraindividual variation could be linked to hypothesized transitions in motivational states as indicated by incidental changes in behavior. Results suggest that vocal development in the willet is based upon innate templates. However, observations also suggest that these forms may be recombined to encode different information.