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Darrell Clegg

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I was looking through an old copy of British Birds from December 1973 (the issue describing the first Ring-billed Gulls in the UK) when I came upon this letter from the late Bernard King. Here it is reproduced in full.

"Probable Sandwich Tern showing runt and albinistic characters
On 11th September 1967, at Porthkidney, Cornwall, Brian Rabbitts and I observed an all-white tern flight-feeding along the tidal edge with about twelve Sandwich Terns Sterna sandvicensis It was a long way from us and, because of its very light plumage and fairly long outer tail-feathers, I thought at first that it might be a Roseate Tern S. dougallii. Some 20 minutes later the flock came much nearer and eventually the birds joined 20 Common Terns S. hirundo and two Arctic Terns S. paradisaea which were resting on the beach. The all-white bird was smaller than the Sandwich Terns but larger than the Common and Arctic; its rather short legs were black, as was its fairly short bill (though there sometimes appeared to be a slight red tinge at the base). The upper- and underparts were pure white throughout, with the exception of a dark mark behind the eye, and the large dark eyes of this beautiful white tern gave it a rather gentle appearance. The outer primaries of the closed wing extended well beyond the forked tail. Eventually it resumed feeding in company with the Sandwich Terns. Its flight and feeding behaviour were very similar to those of its companions, from which it could easily be picked out at a range of about 75 metres.
R. Wagstaffe, then of the City of Liverpool Museums and Bryan L. Sage, author of two papers on albinism and melanism in birds (Brit. Birds, 55: 210-225; 56: 4009-416 ). have both expressed the opinion that this bird was probably a Sandwich Tern showing runt and albinistic characters, and I am grateful to them for their help. In the first of the papers on albinism and melanism, the Common, Arctic and Little Terns S. albifrons, but not the Sandwich Tern were listed among the species in which albinism had been recorded in Britain and Ireland; and, as far as I can ascertain, there are no other records of runt terns, at least not of this genus.

Bernard King"

A few things strike me as odd here. First there had been no records of albinistic or runt Sandwich Terns, and yet here is a bird which is both!
The bill is described as fairly short and black with a red tinge at the base - does anyone know of any Sandwich Terns anywhere that have shown this feature?

In flight the bird had long outer tail feathers making it look like a Roseate on first impression, (again has anyone ever seen a Sandwich Tern with long outer tail feathers?) yet on the ground the wings extended well beyond the tail!

The black legs rule out Forsters Tern, but does anyone have any idea what this bird may have been - is it really just a Sandwich????

Darrell
 
Weird!

The short legs & bill both suggest Arctic, yet it is stated as larger than this on the ground. Roseate has longish legs & bill, so I guess that can be ruled out.

Black legs & bill may indicate immaturity, perhaps a 1-st summer, if so presumably the tail streamers might be even longer as an adult

Otherwise, I wonder about the possibility of Arctic x Sandwich hybrid, with the albinism a consequence of poor genetic compatibility of the parents? Does that sound plausible to anyone?

Michael
 
Michael Frankis said:
Nope - Forster's Tern has red legs at all ages (Darrell already spotted that one!)

Michael

Dammit! Just re-read the original posting, shoulda known Darrell would have had that one covered.
 
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