[All photographs copyright, Gary Nunn 2015] – This interesting hybrid Aythya diving duck was first reported by Elias Elias at Upper Otay Reservoir on 09 Feb 2015. I made a trip out there late in the afternoon the next day and found it was still around mingling with the large number of Ring-necked Duck and Lesser Scaup on the reservoir. It appears to be a hybrid Ring-necked Duck X Scaup sp. and has intermediate physical characteristics of these species. It’s rather chunky large size, and very fat cheeked lower face, makes me think it could perhaps be a hybrid with Greater Scaup. In direct sunlight the head appeared to have a mixed purple and green gloss. However the sun sank behind a nearby hill just after I arrived, so no colors were apparent after that.
The back color appears to be a very dark gray. When viewed from the rear the back actually does look mostly blackish and very cleanly demarcated from the white looking flanks. In the bright sunlight the flanks appeared white but after the sun went down it became apparent they were actually a very pale gray. The flank coloration can be seen when the bird lifts its white belly out of the water. In several of the photos posted below the shape and color of the flank feathers can be seen clearly in comparison to nearby Ring-necked Duck and Lesser Scaup.
I think the bill is the most interesting feature of this duck. It is a typical bright scaup blue but has a large black nail at the end much like that found on a Ring-necked Duck. It also has a broad white banding around the nail again like Ring-necked Duck. However at the base of the bill it lacks the obvious looking white facial border banding found in Ring-necked Duck. The head shape looks plain weird to me kind of a muscular and more oval version of Ring-necked Duck? The large nub sticking out the rear crown looks more Ring-necked Duck than Lesser Scaup to my eye. An interesting creature for sure!