First winter Black-headed Gulls with some all-white tail feathers

I was at a meeting at the Stirling University campus today, so I had a quick look at the birds loafing around the west end of the loch. The birds were concentrated in the few areas of unfrozen water, although the thaw does seem to be kicking in, for now.

I was surprised to see two first winter Black-headed Gulls with white feathers in their tails. I do not know whether this is very early moult, aberrant or leucistic plumage, or the result of damage.

The upper bird has one white T1 (one of the central of six pairs of tail feathers, or rectrices; the feathers are numbered from centre of tail T1 to the outer tail feathers T6) and the lower bird has a white T4 and T5 on the left. In the second shot the upper bird and lower bird have reversed positions.

This bird is showing reduced black subterminal bar in both outer tail feathers (T6) - a common pattern.

With all the snow around, this Grey Squirrel seemed to be feeling a few hunger pangs...