Labrador Duck - or not?

I came across this interesting note via Facebook the other day and thought it was worth sharing here:

McCarthy, E. M. 2014. Labrador Duck: Not extinct after all? http://www.macroevolution.net/labrador-duck.html#.UwzxwONdUSb

This short article suggests that what is described as the long extinct Labrador Duck (Camptorhynchus labradorius) is merely the result of a pairing between a Steller's Eider (Polysticta stelleri) and Common Eider (Somateria mollissima). The author's line of evidence for this supposition includes the apparent historical rarity of the species, the discovery that all the eggs supposedly from Labrador Duck on collections were determined to not be from this species through genetic analysis, rather wide plumage variation in the remaining specimens, and the historical descriptions of a number of other hybrids birds that were originally thought to be full species. He notes that the name of the duck is misleading and has a rather tenuous connection with Labrador, a point that I find unrelated to the matter at hand and other examples of name mismatches are rather easily found in the common names of North American birds. It appears that he was trying to make the point that no nests of this species had ever been found, in Labrador or anywhere else.The author then states that the suggested parent species of the Labrador Duck still hybridize along the Arctic Ocean and the offspring look similar to the Labrador Duck. I assume that there are no photos of these hybrids, since the source cited for these records is the author of this note and no photos were provided here.

I was intrigued by this theory, but less enamored with the argument put forth in support of the theory. I find it hard to believe that the Labrador Duck should disappear in the late 1800's when the purported parent species are still rather common and it would be logical to suspect that those hybrids that led to this mistaken designation as a species would continue to be produced. Although he did mention that there are hybrids of these two species that look "similar" to Labrador Ducks, I would expect that at least some of them would look the same? Two of the examples of hybrids once thought to be full species and noted in the text include the Lawrence's Warbler and Brewer's Duck. Both of these hybrids are the result of pairings of rather common species (Gadwall x Mallard and Golden-winged x Blue-winged Warbers). These hybrids, although not common, can still be found today on a regular basis. A quick Google search revealed a number of photos of both species, but no photos of a Steller's and Common Eider hybrid (or a  Labrador Duck).

The best part about the theory that the Labrador Duck is merely a the result of an errant mating between to different eider species is that it can be tested. I look forward to further examinations of the genetic make-up of the remaining Labrador Duck specimens to assess it's status as a bird that may not have quite gone extinct after all.

Labrador Duck by J.G. Keulemans from Rowley's Ornithological Miscellany Vol II

PS. One statement in the text notes that Labrador Ducks were supposed to have a "bad, fishy, sea-duck flavor." The Ornithological Miscellany reference noted above contains quite a few references that note the flesh of the Labrador Duck was quite tasty.