Cooper's Hawks, Accipiter cooperii, move into the Mendonoma Coast in the autumn and over-winter here. They are a little smaller than a Red-tailed Hawk and can be identified in the air by their flap-flap-glide motion. They are amazing, agile fliers. They hunt small birds. Sometimes one will show up near a bird feeder. That's the time to take down the bird feeder so the Cooper's Hawk isn't given a free lunch.
Hal Fogel recently photographed this immature Cooper's Hawk. If it were an adult it would be blue-gray on top instead of brown. Many thanks to Hal for allowing me to share his photo with you!