Greetings... I'm picking up a gadwallian X mallard vibe from the bird,
particularly from the rump and upperparts of the bird with its head under
water behind the main guy. The tertials on both ducks are rather light and
"silvery" to quote that Sibley fellow, which are male gadwall traits, even
in non-breeding plumage. (Do you know when the photo was taken? That might
effect what I'm babbling about here. I'm assuming these guys are not in
"high" breeding plumage).

The bill shape and color on the main bird look pretty good for a male
gadwall. I can't tell from the photo, but the bird in the background seems
to be dabbling, as opposed to diving, and if that's the case . . . and
assuming that these two birds are together because they are ducks of a
feather so to speak, which is taking some liberties, then I don't get a
diving duck feel for either bird.

Mallards are always taking part in Frankenstein combinations of some sort or
another. Usually they have a green sheen to the head, but the purple on this
bird could be the lighting . . . could be of course. I could be well wrong,
as well! The reddish breast and the darker rump are male mallard-style
patterns, but not necessarily proof of anything in this duck. Gadwalls have
"pointy" foreheads, as do greater scaup, but the bill doesn't look scaupish
to my eyes. Anyway... hybrid ducks are a treat of sorts, aren't they?

Take care,
---Mike Busam
West Chester, OH