White-winged gulls in Orkney and Edinburgh, May 2013

Some great gulling last month with three different white-wingers...

Adult summer Glaucous Gull (on right), Egilsay, 16 May 2013 (with 3cy Herring Gull)

Third calendar year Iceland Gull (on right), Westray, 22 May 2013 (with adult Great Black-backed Gull, Hooded Crow and adult Herring Gull)

Adult type feathers in the back of this 3CY Iceland Gull more obvious in this shot

Isabel dilution mutant Herring Gull (centre), Seafield, Edinburgh, 29 May 2013 (with Herring Gulls)

Dark Pomarine Skua (with spoons)

While I was on Westray last week phenomenal numbers of Long-tailed Skuas were passing by in the NW gale. Seawatching in those conditions is not the recommended activity for a party of non-birding teenagers so despite walking the headlands in some outlandish May weather I was unable to watch the long-tailed sea-sprites pass by. Instead I contented myself with a single melanistic (dark morph) Pomarine Skua from the Westray to Kirkwall ferry. Well, I was pretty excited about this at least. No pics of the Basking Shark seen briefly on the same journey unfortunately.

Blue Fulmar in the Pentland Firth

I have been lucky enough to be visiting various of the Orkney islands for the past fortnight. Always a fantastic archipelago - packed with outstanding wildlife, archaeology and scenery - the weather was not the kindest this year and as it was a work visit I was unable to make the most of the birding on offer. For example I missed out on the phenomenal passage of Long-tailed Skuas last week despite being on Westray at the time... not to mention the Garganeys, White-billed Diver, Red-backed Shrikes, etc. Next time?...

Here is my best sighting of the fortnight - a blue Fulmar - an intermediate/dark morph of our Northern Fulmar. Only my fourth sighting of this form, I was pleased to get these record shots as the bird passed the ferry back to mainland Scotland, especially since I failed to get any shots of a probable at Seafield earlier this year.

Northern Fulmar plumage variation

For fear of getting doused in foul-smelling vomit, I didn't fancy getting too close to this young Northern Fulmar on North Ronaldsay, Orkney, in August 2009. As is often the case with the less-appealing types of baby birds, they do tend to mature into beautiful adult birds.

Here are a series of adults photographed from Burness on Sanday a few days before. These birds are all of the typical double-light plumage morph, but I have organised them from darkest to palest. From these pictures it looks as though feather wear may be responsible for at least part of this variation.

Last September I was lucky enough to have an opportunity to snatch some photographs of a 'blue' morph Northern Fulmar while on a pelagic trip off Newcastle (this bird is probably best considered a light morph or intermediate morph; the terminology is confusing in a UK context because blue fulmars are darker than our normal double-light birds but are still considered light in comparison with darker northern birds). This is the best shot, and as you can see it is not the clearest. I really wish that I had asked for the boat to turn to get a second look at this bird, but at the time thought that no-one else was likely to be that interested. Also, I was slightly skeptical that it was a 'real one', but have since found out that there appear to be a small number of resident birds in the North East of this plumage morph. Oh well, I'll get better shots, and, more importantly a better look, next time.

Nice bird? Well, it looked pretty neat in real life, and had quite a grey-blue hue to its head, neck and flanks, and in flight it looked really good, but it is not as dark as more northerly blue fulmars (dark and double-dark morph birds). Note the much heavier marking across the bill, which is typical in the blue fulmar. I managed to pick up another blue fulmar (light/intermediate morph) while seawatching off Buness, Fair Isle, in October and am now quite a fan of them. I must remember to have a look out for one off Lothian over the next few weeks.

On the same pelagic trip there was significant variation in the appearance of the regular morph birds. In the next shot, the rear bird has heavily abraded or moulting coverts (maybe a sign of a failed breeder moulting early) and a yellowish tone to the white head and body feathers, which is quite common.

The bird in the foreground seemed substantially paler in the field and I think the whiteness of its head, body and tail is quite striking. This bird may be similar to the palest bird in the flight shots above. I wonder how different these birds would be to the triple-light morph, which may or may not exist. On the other hand, I think it is possible that they have abraded tail feathers that appear whiter than normal. Anyone know?

Finally, here is another bird with quite serious primary moult. According to BWP, primary moult occurs in rapid succession but growth of outer primaries is slow. That, I think, hits the nail on the head - only a couple more primaries to lose on that left wing, but the new ones have got some catching up to do...

Common Crossbill on Sanday

Mountain biking this morning at Glentress, in the Borders, and the spruce trees seemed to be full of Common Crossbills. We watched two birds at close range perching on one of the poetry-inscribed stones at the edge of the red trail. One looked a typical female type but the other was a lovely (young male?) with pale body feathers and a bright yellow rump. I was wishing that I had binoculars or camera with me - although they might not have been very helpful at other moments...

I grew up with Common Crossbills being regular birds in the trees around the house and, as a result, they are one of my favourite birds. While flocks were seen on a seemingly daily basis, and prolonged views of feeding birds could be had regularly, it was a rare event that really good close views could be obtained.

Strangely, after a childhood surrounded by conifers, my best ever view of a feeding Common Crossbill was on the virtually tree-less Isle of Sanday, Orkney, in the summer of 2009.

We had just arrived at a cottage that we had rented for the week at the Peedie Sea and to welcome us a Common Crossbill flew in to watch me unpack the car boot. It appeared to be a second year male, as it was pretty red but also showed quite a number of immature feathers, and it also showed a thin but distinct wing bar caused by narrow pale fringes on the greater coverts. After sitting on the fence for a while it was soon tucking into grass seed and it fed in the area on and off for the next few days. Hopefully it made landfall elsewhere later in a more suitable habitat...