357. Notes on the vocalizations of Brewer's Sparrow (Spizella breweri)

Song of both races is structurally similar. Vocal differences have already been documented and discussed (Spencer 2014), from where the following extract: The full song of breweri typically sounds very buzzy throughout, descending from very highpitched, insect-like buzzes to lower pitched buzzes, but rarely having anything that one would describe as “musical” about them. This is due to the broadband nature of all of the elements of the song. Most phrases in the long song are made up of two alternating notes that comprise the buzz, and in nominate breweri both of these elements are broadband, or if one is less so then the broadband one dominates. The full song of taverneri, on the other hand, gives a much less buzzy impression. The overall structure of the song is the same – it typically starts out with very high-pitched, insect-like phrases that quickly descend into the variable series of trills. The difference comes in the fact that elements of the majority of the phrases in the song are noticeably less broadband than in breweri, so that they sound more musical and tinkling. This difference isn’t huge, and there is considerable variation, so it is important to listen to enough of the song to get a general impression rather than make the call on just one or two elements.