Spot the odd one out

[leeperry]

Can anyone spot the odd one out and why.
I liked the composition when I took the image, of the group of three in a huddle and the single guillemot one looking on.
It was not until I got home and read up on Guillemots, that there is natural "odd one out" in this image.

Spot the odd one out by Gary Cantwell, on Flickr

[Trev B]

Re: Spot the odd one out

The one looking on is the 'Bridled' form of the species -- white eye ring and line running away from the eye

[antoeknee]

Re: Spot the odd one out

Brindled were once considered a subspecies but now thought to be an example of dimorphism.

[leeperry]

Re: Spot the odd one out

Thanks guys for the extra info.
In my RSPB hand book, all it said was " Some northern birds have a white spectacle marks on their faces."