Unusual Guillemot winter plumage? (1 Viewer)

[Stonefaction]

Way back before I got (back) into birding I photographed a Guillemot on the river Tay in Dundee, Scotland on 28 December 2005. Having posted a photo of the bird on flickr, a few years later I was approached by someone asking to use the photo in an article for Dutch Birding (no idea if the article ever came to fruition or not) as the facial markings were apparently more reminiscent of Brunnich's Guillemot in winter plumage, and the author wanted to show how Brunnich's-like Common Guillemot could look. The bill length and apparent dark streaks on the flanks are certainly indicative of Common though I did then wonder about the possibility of hybrids - I'd never heard of Brunnich's Guillemot in 2005, and couldn't find any indication of hybrids when I searched but thought that it was an interesting looking bird. Given the current discussion on the Fife Brunnich's and the suggestion by some of hybridisation, I thought I'd post these photos, (which I thought I'd lost bar the 1 on flickr), for discussion.

 

[Andrew Whitehouse]

I saw a very similar bird to this over weekend Barry. I usually assume ones like this are in some sort of transitional plumage that gives them this 'pseudo-Brunnich's' plumage. I don't think there's anything structurally in this bird (or the one I saw the other day) to think it might be a hybrid. It still looks totally Common Guillemot on shape and, as you say, plumage features like the flank streaking are normal for Common too.

 

[Stonefaction]

Thanks, Andrew. A transitional plumage was my own 'best' explanation for the head markings, though I wasn't sure how advanced back into breeding plumage a bird in late December was likely to be. Couldn't see anything similar when I searched for photos, though that may have been down to my search 'terms' used, or maybe nobody bothers photographing winter Guillemots.

 

[Andrew Whitehouse]

Thanks, Andrew. A transitional plumage was my own 'best' explanation for the head markings, though I wasn't sure how advanced back into breeding plumage a bird in late December was likely to be. Couldn't see anything similar when I searched for photos, though that may have been down to my search 'terms' used, or maybe nobody bothers photographing winter Guillemots.

I regularly see Guillemots in partial breeding plumage throughout the autumn and by New Year a lot tend to have close to full breeding plumage. I guess most are a bit far away to photograph easily, so that's maybe why it's hard to find pictures of similar birds.

 

[Stonefaction]

Handy to know. Thanks.