Last year, I managed to get pictures (myself!) of a young White-crowned Sparrow still molting into that beautiful black and white, stripped crown. At that stage they look a bit checker-boarded in tan, leading to confusing them with this tan variety of White-throated Sparrow. You can see my post and pictures here.
The bird I saw today had a definite light throat…though not as white as the ‘normal’ version and it had the stripped head…though the contrast was not nearly that of the more common version, either. It had a clear, dark line through the eye and a long tail that it kept somewhat ‘cocked’ as it scratched about beneath my kitchen window where a thistle-feeder hangs; not like a wren, but more so than say a Junco. The bird above looks much like the bird I saw: brown stripes with tan, rather than white, alternate stripes.
You can read about this bird, in all its versions here; they also have a recording of its call and a video of its behavior on the ground. The report there, discusses the difference in the two color forms, as well as mentions individuals almost always mate with a bird of the opposite morph and that the white-stripped birds are more aggressive than the tan-stripped ones. Oddly, both color types prefer females with white stripes, but both kinds of females prefer tan-stripped males. These genetic differences are unique among birds. The bird to the right is the white-stripped version.