A Song for APRIL 11

Click the sonogram to hear and see the sound.

Towhees are known for singing "Drink-You-Tea," which symbolizes a three-part song made up of a whistle, a click, and a trill. That pattern, however, is more typical of Eastern Towhees, while Spotted Towhees, the western species, may sing two- or even one-part songs. This bird, a Spotted Towhee, exemplifies the latter option. He also exemplified the typical towhee pattern of singing with eventual variety, i.e., repeating the same song-type numerous song-types before switching. The same bird sang differently the next day, alternating a two-part song with the first part alone and the second part alone. I have never witnessed that from any species, before or since.

"Towhee" is a name that has been applied to large, long-tailed New World sparrows of the family Passerellidae. Recent genealogical work based on DNA sequences has shown that towhees are not a single evolutionary lineage, called a clade. That is, some towhees are more closely related to other sparrows than to other towhees. But, the black, white, and rufous birds of North America are closest relatives. The eastern ones, now classified as the Eastern Towhee, are solid black (males) or brown (above), with only a single white patch on the black or brown wings. The ones in the west, the Spotted Towhee, have numerous white spots on the back as well as two white wing-bars. Sibley's field guide points out the great reduction in the size of the white spots in the Pacific Northwest. This exemplifies Gloger's Rule, a pattern observed in many species whereby pigmentation increases with the humidity of the environment. The reason for this pattern remains unsubtantiated, although explanations have been proposed.

The Pacific Northwest is known for rain, but I spent a week on Lummi visiting my friend Luther Allen and never saw a cloud. The weather was perfect and I saw and recorded many birds. The towhee in question was very cooperative, as the video shows. It also shows the dramatic contrast between the back view of an almost solid black bird, to the front view of his resplendant white underparts with bright rufous sides. By the way, singing birds are advertising, so it is not unusual for them to face one direction for a while, then flip and face the other, as this bird did. I had to edit out the switch because of deterioration of the tape. The sound sequence, however, is uninterrupted.

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