Sunday, 18 September 2011

Substandard subspecies

The reports of seawatching off the East Lothian coast over the last few days combined with too much time spent working over the last few months had me (tw)itching to get out. The only window of opportunity was a couple of hours around lunchtime today, so I scooted up to Alnwickhill first (just in case).

A quick scan revealed a nice group of Goosander loafing on the brickwork and a darker than usual Lesser Black-backed Gull. Subspecific identification is a minefield in most circumstances and the large white-headed gulls are certainly no exception. I think it is safe to say that, despite being distinctly darker than any other LBBG in the vicinity (even when seen from a variety of angles), today's bird may be an intermedius Lesser Black-backed Gull rather than the more usual graellsii subspecies or it may not... In this pic the 'intermedius' is standing in front of a subtly paler grey graellsii.

I headed to Torness to watch for seabirds off the power station walkway. My target species was Sabine's Gull which has been seen off the East Lothian coast over the last few days, along with an interesting selection of shearwaters and skuas. Unfortunately, there was little obvious movement offshore other than the obligatory Gannets, and a single Manx Shearwater and a couple of Arctic Skuas. Scanning feeding groups of Kittiwakes and Black-headed Gulls failed to reveal any other species in their midst. Nevermind, there is always next time...

I did manage to see a single Eider - a moulting male - and was not too surprised after Stephen Welch's recent sightings to see that it was sporting some very prominent sails. A borealis Northern Eider then? Well, I think that the identification features of Eider subspecies are a work in progress to say the least. Even in this distant and blurry shot the sails are quite obvious (!).

Finally, a nice candidate for alba White Wagtail (rather than more usual yarrellii Pied Wagtail), gave me the runaround by refusing to reveal its central rump feathering - crucial for the sure identification of the forms. A split second view indicated it was pale grey, and the other features also looked good for alba. In the first picture, the upper rump can be seen to be pale grey, and the mantle is distinctly paler than the nearby young yarrellii, but without a definitive clear view of the central rump area it is difficult to be sure. So, a hat-trick of substandard views of awkward subspecies, but great fun nonetheless.

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