In response to your query about the frequency of crows pursuing
Red-Tailed Hawks... Even smaller birds than crows will get on the tail of
a Red-Tail. I have many times watched one or other of the local Red-Tails
make a speculative pass over the slough in Marymoor Park, and you should
see the response of the males of the Red-Winged Blackbirds that nest
around the slough: they come up like a squadron of x-wing fighters out of
"Star Wars," and they don't just chase, either. I've seen one come down
onto the back of a low-flying Red-Tail and deliver several good pecks before
taking off again!