finally can sort of see what the crows are mobbing, from a distance and through a bunch of trees. it's bigger than the crows, but not a lot, so probably not an eagle; predominant colors are brown and red, so I'm guessing a redtail hawk. aaand I would probably be wrong; this is the wrong area for them at this time of year. hmm...
well, either a redtail or a Cooper's hawk; either is unlikely for this time of year, but nothing else fits the profile. huh!