arctica Dunlin at Summer Leys

Late on Thursday, 9th May, I made a flying visit to Summer Leys LNR in the hope that the strong south-westerlies sweeping southern parts of the UK had brought with them something a little different to the run-of-the-mill birds we have been used to seeing in recent days. I had seen nothing from the feeding station or on the adjacent Mary’s Lake and viewing conditions were not ideal, even from the screen hide, which did not offer as much protection from the strong, blustery wind as I had expected.

I was about to leave when a small flock of Dunlins suddenly arrived in front of me on ‘The Slips’. A quick count totalled twelve, all in smart summer plumage with fresh, bright fringes to the upperpart feathers, although it immediately became apparent that one bird was a little different. Closer scrutiny revealed a slightly smaller individual with less brightly patterned upperparts, grey and buff fringes to many of the mantle and scapular feathers (with black centres), sparse streaking above the black belly patch and a more prominent supercilium and shorter bill than most – if not all – the accompanying birds.

I had little more than ten minutes of observation before a very low-flying Hobby skimmed the water’s surface nearby, flushing the flock, which promptly vanished and I was unable to relocate it anywhere on the reserve.

'Arctic' Dunlin (left) Summer Leys, 9th May 2013 (Mike Alibone). The difference in upperpart pattern is obvious, the bright, rusty fringes of the schinzii Dunlin on the right being replaced by buff and grey in arctica, the latter being a marginally smaller individual (exaggerated in the photograph by the slightly different angles of the two birds relative to each other) while the bill length of arctica is shorter but this is not visible in the image. — ‘Arctic’ Dunlin (left) Summer Leys, 9th May 2013 (Mike Alibone). The difference in upperpart pattern is obvious, the bright, rusty fringes of the schinzii Dunlin on the right being replaced by buff and grey in *arctica*, the latter being a marginally smaller individual (exaggerated in the photograph by the slightly different angles of the two birds relative to each other) while the shorter bill length of *arctica* is not visible in the image.

During this time I shot a series of short, wind-shaken videos through my scope and the best of a bad bunch appears below. The same windy conditions left me with one dreadful and barely usable digiscoped shot (above), which serves to illustrate some of the above differences. To my eyes this bird showed all the characters associated with arctica, ‘Arctic’ or ‘Greenland’ Dunlin, the rarest of the three races of Dunlin (schinzii and nominate alpina being the other two) which occur annually in Britain.

‘Arctic’ Dunlin (left) Summer Leys, 9th May 2013 (Mike Alibone). [Run video, click on cog-wheel icon and change image quality to 720p HD to watch at highest definition].

The UK status of arctica is one of a regular passage migrant in relatively small numbers and supposedly with a westerly bias. It breeds in north-east Greenland and Svalbard and its population was recently estimated to be between 7,000 and 15,000 pairs; compare this with schinzii – the race breeding in the UK, northwestern Europe and Iceland – which has an estimated population of 270,000 pairs in the latter country alone (see Gunnar Thor Hallgrimsson) and its relative rarity becomes apparent!

As far as I know, there are, to date, no other records of this race for Northamptonshire, although it must surely have occurred in the past. Trying to identify one which is not in fresh summer (= early spring, unworn) plumage would be a greater challenge.