Ooh, good eye there Michael. Had to go back and look again and see now
that I didn't scrutinize those mentioned features close enough, noted them,
but just kind of blew over it. So, I think you're dead on, hybrid
back-cross. I liked your "Find the 6 differences between the pictures analogy.
Sounds like a good feature game for "Birding" Magazine, "WOS News", or similar
to play on a regular issue by issue basis, and Kelly's great mind teaser
image here is a good start.

Richard Rowlett
Bellevue (Eastgate), WA


-----------------------------------------
In a message dated 3/7/2012 8:26:51 P.M. Pacific Standard Time,
BirdMarymoor at frontier.com writes:


There are other features indicating hybridization with Common Goldeneye.

If you look in Sibley, he labels the ?black spur? that droops to the
forward end of the scapular spot region. Compare that to Common Goldeneye,
which has a forward-pointing horizontal spike. Your green-headed goldeneye
shows both the drooping black spur and the horizontal spike. The spur also
looks slightly ?funny? ? a bit too blunt and a bit too short to be pure
Common.

If you look at the rear section of the black side patch, there seems to be
a similar difference. A male Barrow?s Goldeneye should have a strong
black bar angling slightly downward connecting the scapular patch to the black
rump. A Common Goldeneye should have just a thin, horizontal black thread.
Your green-head shows much closer to the horizontal black thread.

Additionally, it?s not totally apparent, but it seems to me that the
facial crescent doesn?t quite reach to a sharp point at the top ? just a touch
rounded up there perhaps.

So it seems clear to me that this bird is, indeed, a hybrid. Maybe the
fact that it appears different from ?typical? hybrids indicates that it is a
back-cross bird.

Very interesting. This was very much like the ?Find 6 differences
between the pictures? from the Seattle Times comics page...

== Michael Hobbs
== Kirkland, WA
== http://www.marymoor.org/birding.htm
== http://www.marymoor.org/BirdBlog.htm
== birdmarymoor at frontier.com




From: _Pterodroma at aol.com_ (mailto:Pterodroma at aol.com)
Sent: Wednesday, March 07, 2012 5:32 AM
To: _mcallisters4 at comcast.net_ (mailto:mcallisters4 at comcast.net) ;
_tweeters at u.washington.edu_ (mailto:tweeters at u.washington.edu)
Subject: [Tweeters] Re: Barrows Goldeneye with green head sheen





Wow, fascinating photo capture there Kelly, very striking with both
goldeneyes comparatively in perfect or near perfect juxtaposition relative to
each other and to lighting that 'might' otherwise alter perception of sheen.
In this case even if that juxtaposition is ever so slightly 'off', casting
one head to the light one way, the other, another, it doesn't appear to me
to be enough to make such a striking difference as exhibited in your image.
Plus, it sounds like you didn't notice this feature on any of all the
other Barrow's Goldeneyes assembled and am guessing you probably put in some
time and effort consciously searching for such given this one individual was
such a 'stand out' in the crowd.

One thing I do notice is that the scapular spots are slightly larger on
the 'green' headed bird, smaller in the 'purple' head and more typical or
closer to average amongst Barrow's. Common Goldeneyes have much more white in
the scapulars of course. However, the scapular spots shown on both birds
in your image still lean to looking like 'spots' as opposed to something
vastly more extensively white and this may not be a point to even argue at
all given natural variation among individuals. So, you might have something
curiously interesting there, curious anyway no matter how you slice it, and
it may well have some genes of some 'ancient' Common Goldeneye ancestry as
you tossed out for our rumination.

Richard Rowlett
Bellevue (Eastgate), WA

____________________________________
_______________________________________________
Tweeters mailing list
Tweeters at u.washington.edu
http://mailman1.u.washington.edu/mailman/listinfo/tweeters