Bird observed for about an hour singing in low to medium height sub-alpine shrubs on the south-west side of Angelcomb Mountain. Song was typical of Timberline Brewer's Sparrow; a series of long thin buzzy trills at slightly different pitches. One recording, though faint, captured the song. The bird perched very close at one point, and looked typical of Timberline Brewer's Sparrow, though with a faintly streaked nape, and just slightly less-streaked median crown stripe than the average. However, the crown streak and supercilium were distinctly though finely streaked with grey, and not bright and contrasting as a Clay-coloured Sparrow; and overall this bird appeared quite grey and lacking the buffy-coloured face tones of Clay-coloured. This individual also had very faint, thin, grey streaks at the upper sides of the great which I have seen on Timberline Brewer's Sparrow, and which Clay-coloured Sparrow does not have.