Thursday, 22 December 2011

Semi-retrospective Sandpiper

By Keith Vinicombe

On the morning of Thursday 10 November, I discovered a greyish stint feeding with a Dunlin at the mouth of Hollow Brook, in the north-eastern corner of Chew Valley Lake, Somerset. I simply couldn’t get close to it, but it appeared to have a solidly dark crown, with no split supercilium, and a fan-shaped patch behind the eye. It also lacked any trace of a white mantle V, seemed to show a short primary projection and appeared to have a black shaft line on the feathers of the upper row of lower scapulars, expanding into a black blob towards the feather tips. All these features suggested a juvenile Semipalmated Sandpiper.
Semipalmated Sandpiper (smallest shorebird in centre of image, just right of the much-twitched Sharp-tailed Sandpiper, Chew Valley Lake, Somerset, 19 November 2011). The bird's unsplit supercilium is just visible on this photo. By Richard Andrews.

However, it was just too far away to convince me. I went back the following day and watched it for several hours, but I still couldn’t get any closer. I returned again on 15 November, this time armed with an old 60x zoom lens, which I managed to lose in the middle of a reedbed! I spent half the morning trying to find the bloody thing, which, amazingly, I did. Unfortunately, the views were no better, but I did secure 54 rather poor digiscoped images, none of which was sufficiently detailed to provide the proof that I was looking for. Reluctantly, I came to the final conclusion that I had to let it go.

On the weekend of 19 and 20 November, the stint relocated to Herriott’s Bridge at the southern end of the lake, but it was still distant (300 m). The problem now was that everybody was completely distracted by the presence of a juvenile Sharp-tailed Sandpiper that was in the same flock! I decided to try for better views once the crowds died down, but unfortunately, it left overnight on 20th.

Semipalmated Sandpiper (centre bird, Chew Valley Lake, Somerset, 19 November 2011). Note the dark crown and small fan-shaped patch behind the eye, both just visible on this digiscoped image. By Richard Andrews.

It seemed doomed to remain ‘the one that got away’, but about a week later, I had a light bulb moment. On 19 November, Richard Andrews had photographed the Sharp-tailed Sand from a ringing ride near Herriott’s Bridge. I phoned him and asked if, by any chance, he had the stint in any of his photos. To my amazement, he did, and promptly sent me 14 quite reasonable shots of it. As I opened his email, there right before my eyes, was the confirmation that I had been looking for: it was indeed a juvenile Semi-p, just beginning its moult into first-winter plumage!

Needless to say, I felt both elated and vindicated, but I also felt a little uneasy about claiming a bird retrospectively from a series of digital images. Call me old fashioned, but I prefer to identify my birds in the field. Thinking it over, I decided on a belt and braces approach: I sent the photos to Killian Mullarney, who very kindly and very promptly replied with a strong endorsement of the ID as a Semi-p.

This was the lake’s 10th BB rarity and the 16th American bird of a truly remarkable autumn. Even the ‘Good Old Days’ weren’t that good!

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