Presumed hybrid Lesser x Greater Scaup Farmoor Reservoir

There has been much speculation over the identification of the Farmoor Aythya which was first discovered on the 17th, photographed and initially identified as a Greater Scaup.

After much conjecture and the emergence of some clearer photos, it was thought to be showing more characteristics of Lesser Scaup, but over time it soon became apparent that several of these features were not right for Lesser Scaup, and although some could possibly be found within normal variations others could not.

The first discrepancy that was noted was the overall size of the bird which was noticeably bigger
than the accompanying Tufted Ducks, which can be seen in the video clip and grabs below.
Lesser Scaup are generally considered smaller than Tufted Ducks but the Farmoor bird was not,
(this was even more apparent in flight next to a Tufted Duck).

Video clip of the Aythya hybrid with Tufted Duck and Coot.

Size difference comparable in these video grabs. 

Secondly the vermiculation on the back appear to be too fine for Lesser Scaup with the base
colour of the back too dark, it should appear whiter, also the vermiculations should become
coarser towards the tail which doesn't happen on the Farmoor bird.

But the main concern was shown within the wing bars, with the the Farmoor bird containing white on the outer webs of the primaries to p6 which rarely occurs on Lesser Scaup (see photo below) but is consistent with the wing pattern of Greater Scaup.

The Farmoor Aythya with comparison Lesser Scaup wing courtesy of Ian Lewington.

Greater Scaup

Lesser Scaup

Hybrid Lesser x Greater Scaup have previously been documented in North America and in

the U.K it is also worth considering Scaup x Tufted Duck. 

With thanks to Ian Lewington, & Roger Wyatt.

Photos courtesy of Terry Sherlock & Ewan Urquhart.