In the National Geographic guide, there's a picture of a "tan-stripe
phase" of the White-throated Sparrow that could be what you described.
It looks in the book like a cross between a GCSP and a WTSP.

==Michael Hobbs
==mikeho at microsoft.com
==Redmond WA
----------
>From: Alvaro Jaramillo <alvaro at quake.net>
>To: <tweeters at u.washington.edu>
>Subject: Ducks behavior, rape, and weird sparrow.
>Date: Tuesday, January 23, 1996 11:54AM

> BTW, while I was writing this (just ten minutes ago), the weirdest sparrow
>popped up at my feeder. It was strikingly different from the Golden-crowns
>and White-crowns just with my naked eye. I got it in my binos and only one
>word can describe this thing- WEIRD. It looks intermediate between a
>Golden-crowned Sparrow and a White-throated Sparrow. It is like a
>Golden-crown in size and shape (much larger than a White-throat) but has a
>clear white throat and a pale grey breast that contrasts with the darker
>belly. The supercilium is whitish with a bright yellow area in the
>supralores (anterior part of the supercilum). The lateral crown stripes are
>brown, without any black and there is a pale median crown stripe. Unlike a
>Golden-crown, this bird has an obvious eye-stripe behind the eye. The bill
>is a little smaller than those of the nearby Golden-crowns. The upperparts
>look like a regular Golden-crown's.