Fox Sparrow is due for a split, most likely into four species: Red, Sooty, Slate-colored, and Thick-billed. These are different enough that the illustration should have examples from each of these groups of subspecies. The iliaca subspecies
is so different from the other three that even though it is the
nominate subspecies, it would be very difficult to use the illustration
to identify any of the western races, none of which have streaks on the
crown, and all of which have much smaller patches of white at the
throat.
