domingo, 20 de julio de 2014

Fulmars with dark subterminal tail bands in the N Atlantic



Bob Flood, from Scilly Pelagics has recently posted an interesting video to Youtube (find it here and embedded above) which shows something previously unknown which, as he comments, represents a discovery that Atlantic Fulmars (Fulmarus glacialis) can show dark subterminal tail bands. Something more to look for, beyond finding the interesting 'Blue Fulmar' for those having Fulmars in their waters and seawatches. He has allowed Rare Birds in Spain blog to reproduce the video and his comments (our capitals):

'A key criteria for separation of Pacific Fulmar from Atlantic Fulmar is that in Pacific Fulmar the tail typically is much darker than the uppertail-coverts and contrasts strongly with them (i.e. visible tail either wholly dark or mainly dark forming a contrasting thick band); but not so in Atlantic Fulmar.

This is a striking feature of Pacific Fulmar in all but dark morphs. So, when I saw this intermediate-morph bird in Spitsbergen (North Atlantic) with an obvious dark tail band, I immediately thought it could be a Pacific Fulmar. It would be a first for the Western Palearctic! The video was taken during an Oceanwide expedition cruise in Spitsbergen and I hoped a photographer on board might have photographed the bird so I could check details. No such luck. However, I alerted one of the expedition team Christophe Gouraud (top guy) and, to cut a long story short, we now have good SLR photos of two other fulmars in Spitsbergen with dark tail bands. It appears that there is a population of fulmars in western Spitsbergen (at least) with dark tail bands. How many is unknown.

We have not heard of anything like this before and we find it an astonishing discovery, given that the area is well researched and well travelled; but it begs the question, 'What is going on?' We will give a full expose in the forthcoming multimedia ID guide 'Albatrosses & Fulmarine Petrels' (Bob Flood & Ashley Fisher), and Hein van Grouw (Natural History Museum, Tring) and I will discuss the birds in a forthcoming article. 

We are still working through the possibilities with a few strong candidates on the table. One thing I am fairly confident of is that the birds are Atlantic and not Pacific Fulmars based on structure and other features of plumage aspect (though Pacific genes are not eliminated). So, the ID criteria for separating Pacific from Atlantic Fulmars perhaps will have to be rewritten?'

Bob Flood also comments that recent DNA research recommends elevation of the two forms to species level (pdf in the link): Kerr, K. C. R., & Dove, C. J. 2013. Delimiting shades of gray: phylogeography of the Northern Fulmar Fulmarus glacialis. Ecology & Evolution 3: 1915--1930.

More on the Atlantic and Pacific Fulmars at Birding Frontiers here and in the Scilly Pelagics Fulmarine Petrels DVD here.  Thanks to Bob Flood for this interesting input. And NW Spain seawatchers... keep an eye on this. Who knows!