Tufted Duck x Lesser Scaup hybrid, Ambleside Duckpond, West Vancouver (British Columbia, Canada), 19th March 2007 - copyright Paul Kusmin
(photo ID: 3144)
It seems pretty clear that this bird is a Tufted Duck x Scaup sp. hybrid but whether Greater or Lesser Scaup is involved is not so straightforward. The coarseness of the vermiculations on the upperpart is different from at least some Tufted Duck x Greater Scaup hybrids and I think that is very likely to point to Lesser Scaup parentage. In the two photos (above and below) the darkness of the upperparts looks different - that is often true in Tufted Duck x Scaup sp. hybrids, varying according to light and angle to the observer.
Tufted Duck x Lesser Scaup hybrid (same bird as in photo ID 3144 above), Ambleside Duckpond, West Vancouver (British Columbia, Canada), 16th March 2007 - copyright Paul Kusmin
(photo ID: 3145)
Tufted Duck x Lesser Scaup was the suggested ID for the following bird on the other side of the Atlantic (Tufted Ducks are vagrants among Lesser Scaup in North America while Lesser Scaups are vagrants among Tufted Ducks in Europe, so the hybrid is just as likely to occur on either continent). The identification of this bird was discussed but I couldn't see that any clear conclusions were reached - as always, comments welcome. There is also a video of this bird on YouTube.
possible Tufted Duck x Lesser Scaup hybrid, Møllekrogen (Denmark), 14th October 2016 - copyright Rasmus Strack
(photo ID: 3065)
Tufted Duck Aythya fuligula
Lesser Scaup Aythya affinis