Subject: [Tweeters] Male Cooper's Hawk display flight seen over Capitol Hill
Date: Mar 18 16:28:43 2011
From: Kevin Purcell - kevinpurcell at pobox.com


Around noon on Capitol Hill on Thursday 3/17 I watched a male Cooper's Hawk performing a display flight over the ridge of the hill.

The display flight style is very different from the normal accipter flap-flap-flap-glide. The wing flapping is continuous not intermittent, with a lower repetition rate and high amplitude strokes very like a pigeon in flight. His under tail coverts are pouffed up ("laterally flared" in the jargon): he's excited.

He was in the presence of a soaring female Coop perhaps a couple of hundred feet above ground level. She needed an occasional low amplitude flap to keep up her speed.

The male circled around her as he displayed slowly lost altitude.

He finished off (as he did last time I saw this last year) with a vertically oscillating flight consisting of alternate stoops downward with wings fully tucked and display flight style climbs. At the bottom of the stoop he extends his wings pulls up steeply into the climb portion of the display. He looses altitude as he performs these maneuvers (three in succession this time) before he disappeared from sight at below tree top height.

I've not seen the dihedral flight (a glide with wings held in a V, again like a pigeon) as part of his display.

Last year when I saw what I believed to be the same bird (he's banded) perform an almost identical flight (without a female present) and afterwards he returned to a perch. I couldn't find him after this display.

I couldn't ID the female he was with but she was clearly bigger than him (hence female) and soaring with some regular weak accipter flapping. She disappeared after the display.

I suspect the male is advertising his territory he is displaying over. And that's the main reason for posting here. Watch the sky if you see this sort of display in the Greater Seattle area let Jack Bettesworth know. It might turn up a new nest site.

And the obligatory reminder: If you see or photograph a Coop check for a visual ID band. Make a note of date, time, and location, the band color, which leg it's on and the ID letters.

Jack's bands are blue and the leg leg indicates sex (blue/right=male). Jack also reported that some Victoria, BC banded Coops have been seen in the Seattle area recently: these carry black (= male) or red (= female) bands. Photographs can often reveal IDs that binoculars can't. If you have a camera with you try a photo!

http://www.wos.org/research.htm
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Kevin Purcell (Capitol Hill, Seattle, WA)
kevinpurcell at pobox.com
http://kevinpurcell.posterous.com
http://twitter.com/kevinpurcell