Rufous-crowned Sparrow, Aimophila ruficeps


Rufous-crowned Sparrow, 3/27/09, Ed Levin Park
The photos were all taken in the same place, the trail above Sandy Wool Lake in Ed Levin Park, east of Milpitas in the Diablo Range. The first three, taken in March, show adult birds in still relatively fresh plumage, against the green grass of spring; the next two, in July, show adults in worn plumage, against the dry brown grass of summer. The last four, also in July, give a relatively rare photographic view of Rufous-crowned Sparrows in their cryptic and briefly-held juvenal plumage.


Rufous-crowned Sparrow, male, 3/27/09, Ed Levin Park


Rufous-crowned Sparrow, male, 3/27/09, Ed Levin Park
The bird above, in only moderately-worn March plumage, shows distinct rufous striping on the back, and well-defined white linings to the primaries. The bird below, with plumage extremely worn in July, had the back stripes and wing linings mostly blurred out.


Rufous-crowned Sparrow, 7/19/10, Ed Levin Park


Rufous-crowned Sparrow, 7/19/10, Ed Levin Park


Rufous-crowned Sparrow, juvenile, 7/21/10, Ed Levin Park, Milpitas
The juvenal plumage of the Rufous-crowned Sparrow typically lasts only into late September, and as these birds mostly stay low in the grass during this period, is not often seen and much less often photographed. Notable features are the absence of any rufous in the crown, the presence of rufous in the tail feathers, and streaking on the breast and flanks. Brad Schram has a good discussion of this plumage in Western Birds.


Rufous-crowned Sparrow, 7/21/10, Ed Levin Park, Milpitas
The bird in the pictures above and below has an all-gray bill, in contrast to the juvenile first shown, which has yellow in the bill. Though the birds popped in and out of the grass as I was photographing them, I did see two at the same time, so there were at least two.


Rufous-crowned Sparrow, juvenile, 7/21/10, Ed Levin Park, Milpitas
The frontal view shows the streaking on the underparts, and the faint light-dark brown streaking of the crown, with a short paler central stripe. Note in this picture as well as the others that the darker brown eye-stripe, which will be rufous in the adult, breaks the white eye-ring in the rear.


Rufous-crowned Sparrow, juvenile, 7/21/10, Milpitas
This bird appears to have a partially yellow bill, like the juvenile first pictured. But unlike the birds in the other three pictures, this one shows no rufous in the tail. I suspect it is a third juvenile bird in the same family (though I never saw three birds at the same time), but the lack of apparent rufous may be a photographic artifact and this may be another photo of the bird in the first picture.