At Martha Lake, a suburbs about 30 miles north of Seattle, I observed a
falcon and an accipiter circling high overhead. The falcon was
approximately half the size of the accipiter, and they were too far away
to see any markings; just the stereotypical silhouettes.

One would accelerate towards the other, which would bank away, and then
they would resume the circling (and rising on an updraft). I was
fascinated by this interaction; craning my neck for the 3-4 minutes it
lasted (which no doubt entertained the nearby expresso-stand employee ;-)

The falcon is the one that broke-off the engagement by going into a
pattern of steady wing-beats off to the southeast. Also note that while both
these birds were circling in the updraft, they used shallow wing-beats.

As far as identifying goes, they both appeared rather light on the
undersides, and the accipter appeared pin-headed. I don't recall
which of the accipiters was described as relatively small headed in
proportion to body, would someone be willing to share that field mark?
My estimate to size was the accipiter on par with a crow, which only
rules out the sharp-shinned...

I would enjoy hearing of other inter-specific raptor encounters, as I look
forward to the great raptor-watching that the northwest fall and winter
offers.


Michael Patrick
mpatrick at eldec.com
(206)743-8204