Michael Patrick related a falcon/accipiter interaction and asked about other
inter-specific raptor encounters.

Ah, yes, standing in a public space and looking up, squinting to follow a bird
or birds circling up there. And then when you look back at the world below you
find yourself being scrutinized by less fortunate people. But looking up has
netted me the following inter-specific raptor encounters:

Bald Eagles chasing Osprey, attempting to kleptoparasitize (what a great
word), often successfully. Well known, I dare say. On the other hand, Bald
Eagle perched in a favorite perch, dive-bombed by an adult Osprey, probably
less frequent. But seen on several occasions in Seattle's Discovery Park.

Peregrine Falcon chasing Bald Eagle over Green Lake, Seattle. The Peregrine
spent a fair amount of time at the lake that winter and was flying after the
adult eagle, while kakking. Which would mean the Peregrine was defending
something, in this case probably the lake as her hunting grounds. The
(somewhat underexposed) picture shows both birds banking and I use it
frequently to illustrate the difference in flight silhouette between eagle and
falcon.

That same Peregrine also "attacked" Cooper's Hawk as well as Northern Harrier,
flying over Green Lake. However these attack's were executed in silence. The
pictures of the Northern Harrier incident show the falcon diving and the
Harrier upside-down, presumably readying talons to fend-off the falcon.

Last winter I reported on a falcon at the West Seattle Freeway bridge chasing
an Osprey, carrying a fish, flying along the Duwamish River (I'm still not
sure which species of falcon, it was awfully big compared to the Osprey).

At the Samish Flats, I (and a bunch of others present at the time) have seen
interaction between Gyrfalcon and Northern Harrier. The Gyrfalcon perched, the
Harrier flying at the Gyrfalcon, presumably in protest. The Gyrfalcon has a
habit of kleptoparasitizing the Harriers, relieving them of voles or other
small rodents.

Also at the Samish, last winter, I saw a peregrine take off with great
purpose. When I scanned ahead in the direction she (based on size) was flying
at first I only saw a lumbering sub-adult Bald Eagle, seemingly on a collision
course. On closer inspection the Bald Eagle turned out to be in pursuit of a
very small falcon, presumably a Merlin. Through the scope I focused on the
Merlin, which was carrying prey in its talons. It appeared to be pulling away
from the eagle. However when the Peregrine arrived on the scene the Merlin
dropped the prey and fled. The Peregrine caught the prey in mid-air, turned
and came back to its perch two telephone poles from where I was standing. The
eagle also turned and disappeared in the distance behind the dike. The
Peregrine ate the shorebird (Sanderling I believe).

Two winters ago, at the Samish Flats, Ed Deal and I watched a Peregrine chase
a Gyrfalcon. Because of buildings blocking part of our view we each
temporarily took our eyes/scopes off the birds to change vantage point. One of
us would keep the birds in view and describe the background so that the other
might relocate the chase in his scope. Ed relocated the birds based om my
description, we thought, but when I decsribed the birds as disappearing behind
the dike, he reported watching his Peregrine chasing a Gyr up in the air. The
birds I was watching reappeared and circled back, and I could see the Gyr was
brown. The birds Ed watched circled back and what turned out to be a gray Gyr
landed on a piling. It was still being dive-bombed by the Peregrine. Then the
two birds I was following flew right past the gray Gyr. The brown Gyr vanished
to the south and the two Peregrines, by size a male and female, flew off to
the east. Needless to say Ed and I were quite excited.

Back in Seattle, last winter, I was at the grain terminal one morning watching
the one surviving young male raised by our downtown nesting pair of
Peregrines. The young Peregrine was chasing an unrelated adult female
Peregrine, food begging. At one point she appeared to actually present food to
him, then she chased him. After she left (with the prey, a partly eaten
pigeon) the young male was flying near the terminal when he spotted something
to chase. A male American Kestrel. The Peregrine made one dive at the Kestrel,
which evaded him and then swiftly turned the tables on him, literally flying
circles around him and buzzing him from every direction. The young Peregrine
appeared quite taken aback, or at least he quickly landed and ducked his head
as the American Kestrel made one last dive past his head before leaving the
scene and continuing north .

I'm sure I'm forgetting some observed incidents. That's all I can think of at
the moment, hope it's what you had in mind Michael.

Martin Muller, Seattle
martinmuller at msn.com