Keith,



No doubt we can't rely on our eyes, but Howell & Dunn cite the following
Kodak Gray Scale tones for:



Glaucous-winged Gull 5-6

California Gull (californicus) 6-7.5

Vega Herring Gull 7-8

Western Gull (occidentalis) 8-9.5

Slaty-backed Gull 9.5-11.5



So Slaty-backed should be at least as dark as the darkest local Western,
Vega slightly paler than a relatively pale local Western (or roughly the
same if the Western has a bit of Glaucous-winged blood), assuming the
lighting is consistent.



Gene Hunn

18476 47th Pl NE

Lake Forest Park, WA

enhunn323 at comcast.net



From: tweeters-bounces at mailman1.u.washington.edu
[mailto:tweeters-bounces at mailman1.u.washington.edu] On Behalf Of . KDB .
Sent: Tuesday, March 11, 2008 12:41 PM
To: tweeters
Subject: [Tweeters] re: Slaty-backed Gull Again



...one more note: as I just walked in to sit in front of my computer, I
noticed that my monitor portrays the gull as rather light mantled when
viewed at an angle.
As I sit directly in front of it the gull appears decidedly darker backed,
as it did in the field.
For anyone looking to judge shades of gray from online photographs, the
optical illusion at:
http://web.mit.edu/persci/people/adelson/checkershadow_illusion.html
is a must see!!
Thanks again,
Keith Brady
Olympia, WA

_____

Connect and share in new ways with Windows Live. Get it now!
<http://www.windowslive.com/share.html?ocid=TXT_TAGHM_Wave2_sharelife_012008
>