There were a few of the 1st-basic plumage males that showed the somewhat Rusty appearance though, like the bird on the right. The head makes you think Rusty at a glance, but the tertials and greater coverts always lack the rusty edges which all plumages of fall Rusty shows. A few of the Brewer's were more heavily marked than this individual.

Only saw a handful of Rusties with this flock though.