Treated as a species and described from specimens last collected in the 1870s, the Labrador Duck (Camptorhynchus labradorius) is supposedly extinct. Thus waterfowl expert John C. Phillips (1922, vol. 1, p. 34) commented that, "During the ornithological history of this country only one species of North American duck has disappeared, namely, the Labrador Duck."
Labrador Duck is a synonym of Pied Duck, the vernacular name used by early writers such as John James Audubon, who in his famous Birds of America (1840-1844) listed it under the binomial Fuligula labradora.¹
But in fact, it seems that descriptions of this "species" were based on specimens of what were probably natural hybrids of Steller's Eider (Polysticta stelleri) and Common Eider (Somateria mollissima). Indeed, the obvious eiderlike character of these ducks is reflected in the French name for C. labradorius, "Eider du Labrador." Like eiders, they were sea ducks that fed on small shellfish, most commonly mussels, and their flesh is said to have had the bad, fishy, sea-duck flavor of eider. Its bill, too, in having a wide, flattened tip with numerous interior lamellae, was very similar to that of a Steller's Eider, but quite different from those of other ducks. Indeed, in a phylogeny based on 120 separate morphological characters (Livezey 1986) Camptorhynchus grouped closely with Polysticta and Somateria.
Sibley and Monroe (Distribution and Taxonomy of Birds of the World, 1990, p. 40) state that the characteristic habitat of C. labradorius is unknown, and that it was last recorded in 1878 (USNM specimen number 77126). They also note that it was "alleged to have bred in Labrador" and was recorded from Nova Scotia and New Brunswick south to New Jersey, and inland to Quebec. It's not surprising that they use the word alleged since "knowledge" of these ducks breeding in Labrador — or anywhere else for that matter — apparently derives solely from the third-hand information given in the following passage in Audubon (from his section on the Pied Duck):
Although no birds of this species occurred to me when I was in Labrador, my son, John Woodhouse, and the young friends who accompanied him on the 28th of July, 1833, to Blanc Sablon, found, placed on the top of the low tangled fir-bushes, several deserted nests, which, from the report of the English clerk of the fishing establishment there, we learned to belong to the Pied Duck.
Eggs provide no clue to the locale of the Labrador Duck's breeding ground. In a genetic study, Chilton and Sorenson (2007) showed that all eggs formerly assigned to this bird were actually misclassified. So no eggs from Camptorhynchus are known.
Such is the gossamer basis — other than an early mention of two birds sent to Sir Joseph Banks from Labrador (Wilson and Bonaparte 1831, p. 218) — for naming this duck Labrador. As William Dutcher later wrote (quoted in Rothschild 1907, p. 105),
we do not know for certain where the breeding haunts of this Duck have been, and that anyone has ever visited them. All information known about the breeding of this bird is that of Audubon, who says that his son was shown empty nests on the top of bushes, which a clerk of the fishing establishment told him were those of the Labrador Duck. This information is certainly too uncertain to draw any conclusions from, but the breeding places might just as well have been much further to the north, and probably were.
Moreover, it's well known that hybrids have often been formally described as species. For example, Audubon treated Mallard-Gadwall hybrids as a species, "Brewer's Duck" (Anas breweri), and hybrids of yellow-shafted and red shafted flickers as "Ayres' Flicker" (Colaptes ayresi); two other rare birds Audubon described as species, Dendroica carbonata and Emberiza townsendii, probably fall into the same bucket (McCarthy 2006). Likewise, for more than fifty years, American ornithologists treated as species (Vermivora lawrencei and V. leucobronchialis) two different types of birds derived from hybridization between the golden- and blue-winged warblers (Vermivora chrysoptera and V. pinus). Many other such examples are given in McCarthy (2006).
Flannery and Schouten (2001, p. 60) comment that "For a species whose winter range included a well-populated region, remarkably little is known about it. This may be due to the fact that it was always apparently rather rare." He goes on to say (p. 61) that only 31 museum specimens are known (Chilton and Sorenson, 2007, state that there are 55). Even Audubon, writing in the early 1840s when most North American birds were far more plentiful than today, described it as rare. And at a yet earlier date, ornithologist Charles Lucian Bonaparte (1826) described it as "a very rare and beautiful species." Another famous expert on American birds, Alexander Wilson (Wilson 1832, vol. 3, p. 114) noted that "This is rather a scarce species on our coasts, and is never met with on fresh water lakes or rivers." Between 1840 and 1860, according to Dutcher (1891, pp. 201-202),
there were apparently more of these Ducks seen than earlier. This, however, I think, may be easily explained as follows: during the later period there were a far greater number of scientific collectors, and there was a market demand for game and waterfowl which gave employment to professional gunners who shot and sent to market great numbers of birds. During the open season one can see hanging in our markets hundreds and sometimes thousands of Ducks of the commoner varieties; this has been the case for many years, perhaps to a lesser degree formerly because the demand was not then so great. While it is very probable that the Labrador Duck was more numerous at the time when Wilson and Audubon wrote of it, than during the subsequent period when it appeared to be more plenty, yet, I think my explanation of their apparent increase is the true one, and, even at the date when they were seemingly becoming more numerous, they were on the verge of their disappearance, for during the period from 1860 to 1870, when an active lookout was kept for them, none could be obtained.
The very rarity of the specimens is suggestive of the idea that they are hybrids, as is the high level of plumage variation apparent in Google images of various specimens held in museums. High levels of variability are especially characteristic of hybrids. Moreover, the plumage and bill coloration of these ducks combine the patterns seen separately in Steller's Eiders and Common Eiders, two birds that are reported to produce natural hybrids (McCarthy 2006). Specimens assigned to C. labradorius have a black back and neck ring, as in Steller's, but a black crown and belly as in Common Eiders (see pictures above and at right).
Steller's Eiders and Common Eiders come into contact and interbreed along the shores of the Arctic Ocean (McCarthy 2006). Their hybrids are not common, but are, in fact, occasionally seen. The sidebar at right provides a more detailed discussion of present and past regions of breeding contact between these two eiders.
So maybe we've been mourning without reason the demise of "a very rare and beautiful species." Perhaps Camptorhynchus labradorius is just another instance among hundreds of cases in which birds once treated as species turned out to be hybrids.
This entire article has been speculation, of course, and does not prove anything. But given the points covered here, the status of the Labrador Duck does seem rather doubtful. Fortunately, it will be quite easy to resolve this question by making genetic comparisons between museum specimens and the putative parents. If these specimens are hybrids, they would, presumably, be F₁ hybrids, which would make the analysis fairly straightforward (for more information in this connection, see the sidebar "Genetic Issues" above).
It would certainly be nice to cross even one name off the extinction list!
Synonyms
(Source:
Anas labradoria J. F. Gmelin, 1789
Anas labradora Latham, 1790
Rhynchaspis labradora Stephens, 1824
Fuligula labradora Bonaparte, 1826
Somateria labradora Boie, 1828
Kamptorhynchus labradorus Eyton, 1838
Camptorhynchus labradorus Bonaparte, 1838
Camptolaimus labradorus G. R. Gray,1841
Camptolaemus labradorus Lichtenstein, 1854
Camptolaemus labradorius Baird, 1858
Anas labradorica Hall, 1862
Fuligula labradoria Seebohm, 1885
Camptolaemus labradoricus P. L. Sclater,1880
Camptolaimus labradorius Stejneger, 1883
Female Labrador Ducks Female Labrador ducks raise a separate issue. They do not resemble eiders. So what do they mean for this theory? Well, one obvious possibility is that they may represent some hybrid of another type and have only been mistakenly identified as female Labradors. This sort of thing happens fairly often with rare hybrids. After all, without genetic testing, how can anyone really know that these males and females are both the same kind bird? No one ever saw them nesting together (or even during breeding season). To date it seems no such tests have been carried out. Another thing that occurs in a wide variety of avian hybrid crosses is for all, or nearly all of the hybrids to be male (McCarthy 2006). Such is the case, for example, in such crosses as pigeon × turtle dove or canary × twite or chicken × common peafowl (ibid.). If the same holds for the cross currently under consideration then male "Labrador Duck" specimens would represent a monosexual, probably sterile, hybrid (monosexual avian hybrids tend to be quite sterile). There would be no females, which would explain why not a single Labrador Duck egg is known.
Geographic Issues It has been objected that the regions where hybridization can potentially occur between Steller's and Common eiders are implausibly distant from the northeastern U.S. where most Labrador Ducks were collected. Indeed, these birds come into regular contact during breeding season only in Alaska and eastern Russia, and along the southern coasts of the Kara and Barent's seas (compare map in Nygard et al. 1995 pdf with the map at the top of this page; see also Atlas of European Breeding Birds and Pearce et al. 2005), and both these regions are far distant from New England. However, the breeding range of the Common Eider is circumpolar (see map at top of this page). So potential hybridization with vagrant individual Steller's might well occur almost anywhere in the Arctic region. Vagrants often end up producing hybrids because they cannot find mates of their own kind (McCarthy 2006). For example, off the Northumberland coast in the U.K. (Farne Islands), a Lesser Crested Tern (Sterna bengalensis) returned for 14 years to the same sandwich tern colony, producing hybrid offspring (ibid.). There is really no way to know exactly how many Steller's vagrants were reaching North America back in the 19th century, but Steller's populations were much larger then and, perhaps, geographically more extensive. In the 18th century when Steller first discovered it, this duck bred on the Kamchatka Peninsula far south of anywhere it breeds today. However, it is known that vagrant Steller's Eiders reach the Atlantic coast of North America even today. Thus, Toochin and Haviland (2013) state that "In Eastern North America, Steller’s Eiders have been found in the Canadian Eastern Arctic, Quebec, Maine, Massachusetts and Greenland" If these individuals paired up with resident Common Eiders, say in northern Labrador, then their hybrids would have flown south to the northeastern U.S. during winter, and with the larger parental populations in existence at that time, hybrids might well have been more common. Annually, it would not take many such vagrant hybridizations to produce the 55 specimens of Labrador Duck collected during the century between its first description and supposed demise. In some hybrid crosses, because the parents have little propensity to mate, virtually no hybrids occur except when a vagrant is forced to find a mate other than its own kind, which is perhaps the reason why hybrids of this type would be produced primarily in the eastern Arctic of North America where, of all Arctic coast regions, Steller's densities are lowest.
www.macroevolution.net/labrador-duck.html#.UxJ5n4WGeqT
