Posted by Brian Rapoza on January 01, 1970 at 00:00:00
Stephen may be right. My Peterson guide illustrates an immature Brown-headed Cowbird on the House Sparrow page for comparison. The cowbird is illustrated with blurry breast streaks while the female sparrow is not. On the other hand, the Peterson cowbird is illustrated with gray legs and bill, while on Joel's bird, these appear brownish. Definitely confusing.