Tuesday 21 November 2017

Lesser Scaup No Longer 20th November 2017

Well there is nothing like a bit of controversy and debate and the supposed Lesser Scaup still residing with the Tufted Ducks on Farmoor Reservoir has certainly provided that.

Many people came to see the duck on Sunday but amongst us local Oxonbirders slight doubts about its provenance set in mid morning on Sunday with discreet queries arising about its size and the colour of the wing bar.

The final and conclusive verdict came from Ian Lewington, our County Recorder, who visited Farmoor on Monday morning and confirmed the suspicions that it was, unfortunately, a hybrid whose parents were probably a Greater and Lesser Scaup. Such hybrids have been recorded before from both the USA and Britain

Here are the criteria that confirmed it was a hybrid


Lesser Scaup are generally slightly smaller than a Tufted Duck although their size can vary. In flight and when close to Tufted Ducks it could be seen that it was slightly larger than a Tufted Duck


The vermiculations on the mantle and scapulars were too fine for a Lesser Scaup and the base colour of the feathering was too dark and should have been whiter. The vermiculations should have been coarser towards the tail but this was not apparent on the bird in question

Wing bar

This above all other criteria was the most revealing feature.

The wing bar was far too white on the primaries, showing little contrast with the pure white secondaries as there was white on the outer webs of all the primaries up to the sixth numbered ascendantly from the innermost primary (1). This is not consistent with a pure Lesser Scaup.

           With grateful thanks to Oxon Birds and Ian Lewington for the images below

Greater Scaup Wing Bar

Lesser Scaup Wing Bar

So a bird that at first was just very rare became an education and exercise in detective work as to its true identity and was revealed to be a hybrid which possibly is even rarer than the real thing!

Commiserations must go to the lady birder who travelled all the way from Glasgow, having never seen a Lesser Scaup only to find the bird she came to see was a hybrid.

Anyway, it was an exciting few days and I leave you with some more images of the bird.

No comments:

Post a Comment