ID this odd duck?

[nartreb]

I meant to go back for a picture if the bird was still there, but that's not looking likely with this weather...

It was resting on the shore among a group of mallards, and since it looked quite mallard-like at first blush, I almost didn't pay any attention to it. But as I approached all the mallards (except one that was sleeping) slipped into the water, while this one seemed unconcerned. So I got a very good look at it (and still had a side-by-side comparison with a mallard).

It was slightly larger than the mallards. Its head was pure black, except for a vanishingly thin white ring around the eye. The black color extended down the neck to its junction with the body. (The head color and eye ring were similar to a Canada goose, only without the white cheek patch, the long neck, the goose size, etc etc). The bill was partly dark but mostly a sickly pink. I think I recall a trace of a bulbous fleshy growth at the top of the bill.

The secondaries were irridescent green, without any border stripes.

The body was an unremarkable brown, similar to a female mallard. Didn't remark anything about the tail, and never saw the feet.

 

[swamp]

Female Wood Duck maybe?

 

[sardog1]

Sounds like an (American) Black Duck. They often hang out with Mallards. I'll try to post a link later. (Wood Ducks are significantly smaller than Mallards.)

 

[nartreb]

I'm positive it is neither a Wood Duck nor a Black Duck. I am familiar with both.

Black ducks have blue-purple secondaries (with a black border), brown heads similar to female mallards, and yellow (male) or greenish (female) bills. They are also the same size as mallards; my duck was a bit larger.

male black duck note the head is not black...


Wood ducks have a different overall shape (shorter neck), a distinctive head shape, are smaller than mallards, and have quite distinctive coloration, even when "in eclipse" (notably, the back is a different color than the body; males have large white cheek patches; females have white near the eye that extends behind the eye)

male wood duck - note unmallardlike shape

If anything, my mystery duck had a more erect posture than a mallard - more like a muscovy duck.
Picture the head and neck of a female black (i.e., wild-type) muscovy duck (minus any crest or facial knobs) on a body the approximate size and color of a female mallard (but with green, borderless secondaries).

I'm leaning toward a theory that it was a muscovy-mallard hybrid, for lack of better candidates. Black-headed duck (Heronetta) is tempting, but aside from the geographic problem (could have been a pet), they're described as small. (can't find a measurement online). Also, I think I would have noticed the two-tone body color and the very long bill.

 

[Pat T]

Duck ID

How about this? According to Wikipedia, Muscovy Ducks can interbreed with mallards, resulting in a variety of appearance.

Pat T

 

[bryan]

i think rouens looks a lot like big mallards. the irridescent could be cayuga. i suppose all kinds of interbreeding between wild mallards and other domestics could be going on.

bryan

 

[nartreb]

Didn't realize there were so many domestic breeds.

Due to size, posture, and slightly anabolic shape, I'm liking the hypothesis that this is a hybrid of a domesticated breed or breeds with a mallard. The irridescent green on the secondaries does look like the general color of cayuga, so that breed may be in the mix. Maybe black muscovy with cayuga and mallard? (Rouen doesn't add any coloration that mallard wouldn't, and would be *too* large.)