Greetings All

Ahhhh, gull discussions.... like how many angels dance on head of a pin.

Gray scales work great if you have birds side by side, at same angle to sun (even in heavy cloud cover), at approximately same distance... or actually, under those perfect conditions, gray scales work so-so.

A study was done using Munsell scale, experienced goose biologists, and specimens of white-cheeked geese in a controlled-lighting situation. The biologists had the geese and the scale in hand.

Not only was there a fair variation between biologists' rating of the very same bird under the vary same ideal conditions... there was substantial variation (up to 2 points out of?an 8 point scale?as I recall) for the same biologist viewing the same geese under the same conditions but on a different day.

In other words, we are not very good as humans at judging precise darkness, even under ideal controlled circumstances.

So, impressions of mantle colors on a gull, when viewed on one's monitor at home (after?"image" transferred from real life to camera, camera to computer, computer to computer, computer to monitor, and monitor to eye transmission....) are prone to error.

This bird has streaking around the eye typical of SBGU.
It has the head and body shape that is typical of SBGU.
And its bill shape is perfect for female SBGUs, and indeed, the bill size/shape (in my mind) is a strong indicator of SBGU, including vs. Vega.

Steven Mlodinow
Everett WA