[fugl]

I would estimate that upwards of 50 or so of a big tame flock of wintering Canada Geese I walked through this morning at a local park (in Reno, Nevada) had bold white eye rings. Many of these birds also had variable amounts of white flecking on the head and/or neck, but others were completely "normal" except for the eye rings. The flock numbered 650-700 so the proportion of birds with eye rings was fairly high--probably upwards of 7-8%.

Here's photo of one of the "eye-ringed" geese:
http://www.flickr.com/photos/fugl/2935769407/

I've encountered these eye rings in the past, but have never seen references to them in field guides or other literature and have always been curious about them.. I assume that the white blotching and flecking characteristic of many of the local Canadas are the effects of relaxed selection pressures in the safety of the suburbs, and maybe that's also the "explanation" for the eye rings? Does anyone know the incidence of white eye rings among "wild" populations?--very low, I would guess.