Grutness, 16th May 2013
by Roger Riddington and Paul Harvey
A quick post from Shetland to get some feedback about an interesting diver seen earlier this evening. At about 7.30 I got a phone call from Paul Harvey, who’d just seen a stunning, summer-plumaged Black-throated-type diver in the sheltered waters of Grutness voe. Paul was out birding with bins only, was some distance from his car/scope and needed a second opinion – the fact that he couldn’t see a thigh patch on the bird made my journey time that much quicker. Shame I don’t get a company sports car from BB but there you go.
To cut a long story short, I picked up Paul, reunited him with his scope and then we started to grill the bird. The photos below tell their own story really, a bird with a solidly dark flank and an arrestingly small-looking bill. I started to try to photograph it – not so easy in low light, with the scope at x60 and the camera zoomed in to max, but at least there is something. We watched it for about 15-20 minutes, getting gradually more twitchy about it, before it (sadly) flew off strongly. In flight, there was a neat, even black rim around the flanks, with no sign of any indent towards the thigh/rump. At no stage did we see any white in the thigh either, even though the bird was typically sitting quite high in the water.
And – well there’s not much more to say. We’d be grateful of any constructive input! Pacific Diver is a major challenge in summer plumage and it would be interesting to see what people think. Seeing on average one Black-throat a year in Shetland doesn’t make us best placed to judge these things!
A quick interjection from M.G. Not an easy call. Glad that RR and PVH have taken the risk of putting this bird ‘out there’. For me the photo above seems compelling. The area below the rear edge of the wing coverts is the place which is white in Black-throated Diver and dark in Pacific Diver. It appears to be dark, and this concurs with their field views. The bill looks pretty titchy too doesn’t it – and the head/bill combo feels all Pacific. They are asking the critical question in the right spirit. Hope it gets seen again- for them, and for us to learn! As already indicated, comments welcome.