Hi Kevin:

Thank you for posting your falcon observation from the Fill. I'm notably
raptorcentric - I think any day you see a falcon is a good day, and it's
even better when there's an interaction.
Based on what I know of Tundra peregrines in Washington State, I think it is
unlikely that the birds you saw were of the Tundrius sub-species. Adult male
peregrines in this area can and do have beautiful silvery backs - they can
be quite light. The ground color on the underparts can vary a lot, too -
from pale cream to a strong cinnamon wash - depending on the individual.
If the birds you saw were the same size, it was an aggressive interaction
and not courtship, as females are noticeably bigger than males. However, it
can be really difficult to determine relative size, since it is often hard
to tell how far apart individuals are from a distance. To make it even more
complicated, courtship interactions often look very aggressive. The first
time I saw a courtship interaction between the pair that nested downtown for
so long, I thought that one of these very aggressive birds had pushed the
other a little too far and that they were having a fight!
Thanks again for the post.


Ruth Taylor
Seattle/Ballard
rutht AT seanet dot com


-----Original Message-----
From: Kevin Purcell <kevinpurcell at pobox.com>
To: Tweeters <tweeters at u.washington.edu>
Cc: Kevin Purcell <kevinpurcell at pobox.com>
Date: Friday, January 30, 2009 6:04 PM
Subject: [Tweeters] Pair of Tundra Peregrine Falcons (?) over the
MontlakeFill today


>Out walking the Fill in mid-afternoon around 3pm after wondering were
>all the passarines were (the breeze was up but the sun was still
>peaking through the high clouds).
>
>I noticed a pair of bird flying tail astern. Falcon shaped. Medium
>sized (bigger than a crow?).
>
>In the bins they were clearly interacting each trying to get the high
>side of the other and dropping talons inducing the lower bird to
>roll. After a couple of interactions like this they split one heading
>back up to the UW and area to the west of it by circling and climbing
>under power (with the occasional soar but there wasn't much
>convection today). The other I lost track of. He stayed in view (in
>the bins but at rather great distance) for between 5 and 10 minutes.
>
>Unfortunately that initial encounter of the pair was a close as they
>came to me when I was thinking more about behavior than field marks.
>But even when circling I got a good view of the underside and the
>upper side.
>
>I was a little puzzled. They were both the same size and colored the
>same: light gray or light bluish gray above and whitish underneath.
>Both clearly with falcon wings and flight style (no flap, flap, flap,
>glide). So it's a falcon.
>
>As the bird climbed I could see the "head" (i.e. the underside and
>side of the throat and face) looked clearly white and the underside
>of the body a bit darker but not quite grey. The upper side of the
>body and wings was uniform light bluish gray (certainly not dark gray
>or dark blue). The tail didn't have any clearly obvious barred patterns.
>
>I'm not great at falcon id (not seen enough of them to know the
>details first hand) but this had me a bit puzzled. I didn't see any
>red or brown on the upper surface or strong tail barring plus the
>size seemed wrong (not delicate) ruling out a American Kestrel. Again
>no dark blue upper surface and no tail barring ruling out a Merlin.
>No dark axiliaries so not Prairie Falcon (and it's out of
>range ... :-) ).
>
>So that leaves a Peregrine or Gyrfalcon. So two Gyrfalcon over
>Seattle would be a bit too incredible. Plus in the photos and
>drawings I've seen of Gyrfalcon they seem more bulky than this.
>
>So I get to a Peregrine. but shouldn't it be darker above?
>
>In "Hawks in Flight" I see they mention the subspecies tundrius as
>"Adults are light grey above. Some individuals show a blue-gray cast
>on the back and tail. The paler tones, coupled with a more restricted
>facial pattern, mute the bold helemeted appearance of the anatum".
>
>This is a very close match to what I saw (including the white "head").
>
>So I believe I saw a pair of Falco perigrinus tundrius over the Fill.
>
>Comments welcome.
>--
>Kevin Purcell
>kevinpurcell at pobox.com
>
>
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