Voice.—Aretas A. Saunders contributes the following study of the songs of this warbler: “The territory song of the blue-winged warbler consists of two long, buzz-like notes, the second usually lower in pitch than the first and rougher in sound, bzzzzzzz-brrrrrrrr. The pitch interval between the two notes varies from one tone to four and a half tones, but the smaller intervals, one tone and one and a half tones, are much commoner. The second note is lower in pitch than the first in about 75 percent of my records, and higher in most of the others. In a few songs the second buzz is a double note, and one may hear both lower and higher notes from a medium distance, only the lower from a greater distance, and only the higher when very near the bird.
“The pitch is not high as compared to other warblers, ranging from C ‴ to D ‴′, one tone more than an octave. The territory song commonly begins on some note from A ‴ to C ‴′. It varies in time from 11⁄5 to 14⁄5 seconds, the first note being either equal to or shorter than the second. The second note is often twice as long as the first. In some songs the second note is broken into two notes, and in one record it is in four short notes, so that the song is essentially like that of the golden-winged warbler.
“After the birds have been on the breeding grounds for a week or two, singing of the nesting song begins. This song has the same buzz-like quality as the other, but it is exceedingly variable, considerably longer, and hardly ever twice alike. The song often begins with a series of short notes, like tsit tsit tsit, or contains such notes somewhere in the middle. There are usually long buzzes that change pitch by slurring upward or downward. On one occasion, I found a bird that sang a territory song and four different nesting songs. Often the nesting song is sung in flight. By June this song is heard about as frequently as the territory song, and in late summer, after the molt, it is the one most commonly heard.
“The song of this bird is heard from its arrival in spring until early July, when it ceases for a time. It is usually revived in late July or early August, and from then on may be heard fairly frequently until the birds depart about the last of August.”
In his notes sent to Dr. Chapman, Burns describes the song as, “a drowsy, locust-like, swe-e-e-e-e ze-e-e-e-e, the first apparently inhaled and the last exhaled. * * * Another song heard on the first day of arrival, on one occasion, uttered by several males in company, possibly transients here, and may be the mating song, suggests the Chickadee’s che-de-de-e, che-dee-e, and che-de-de-dee, uttered repeatedly in one form or other in excitement, and while running out on the branchlets. The call and alarm note is a rather weak chip.” Dr. Chapman (1912) records a longer song, heard later in the season as “wēē-chĭ-chĭ-chĭ-chĭ, chūr, chēē-chūr.”
Francis H. Allen tells me that the final note, ze-e-e-e-e, as rendered by Burns, “is really a very rapid series of pips, as if the bird had lips like ours and vibrated them by forcing the air through them—in other words, giving a sort of avian Bronx cheer, but high in pitch. The individual pip notes are clear, but the effect of the rapid succession is somewhat buzzy.”
The songs of the hybrid forms may be like the song of either parent form, more often like that of the goldenwing, or a mixture of the two.
The flight song, as heard by Frank A. Pitelka, is recorded as follows:
tsee-
zweé- zweé
tzip- tzip-
zee-zee-zee-zee-zee-zee- zee-zee-zee-zee-zee-zee-
The song of the blue-winged warbler is one of the high-frequency songs; Albert E. Brand (1938) gives the approximate mean as 7,675, the highest note about 8,050 and the lowest note about 7,125 vibrations per second; this compares with an approximate mean for the black-poll warbler of 8,900 vibrations per second, the highest frequency of any of the wood warblers, and an average for all passerine birds of about 4,000 vibrations per second.