Today I finally had a chance to go back and read a couple recent scientific papers that looked interesting, but I hadn’t had an opportunity to review closely. I’d like to bring one particular paper to your attention today and talk a little about the research and the results. Back in October, Clemens Küpper, from the University of Bath in the United Kingdom, and his colleagues published a paper in the journal The Auk suggesting that that Kentish and Snowy Plovers be split into two distinct species.
Let’s start with a little bit of background. The Snowy/Kentish Plover (Charadrius alexandrinus) currently describes a small shorebird that breeds on five of the seven continents and occasionally migrates to Australia in the non-breeding season. This cosmopolitan species is broken down into six subspecies, three in the New World and three in the Old World. The species was first described by Linnaeus in 1758 and in 1858, the New World birds, the Snowy Plover (Charadrius nivosus), were classified as a separate species from the Old World birds, the Kentish Plover (Charadrius alexandrinus). In 1922, the two species were reclassified as a single species due to inconsistencies in plumage differences. Debate continues and most modern taxonomies continue to list these birds as a single species, the Snowy Plover (Charadrius alexandrinus).
Küpper’s research examines multiple populations of these birds looking both at differences in DNA as well as plumage and size differences. After a thorough examination, the molecular data support the conclusion that these are two distinct species. In fact, the data suggests that the Snowy and Kentish Plover split prior to a later evolutionary split between the Kentish and White-fronted Plover, a closely related species. The phenotypic differences, primarily concerning the size, demonstrated that Kentish Plovers average larger than Snowy Plovers, particularly in mass and in wing length.
So the paper clearly concludes that these two birds should be split into two species, but what does this mean to us as birders and scientists? Well, it has numerous implications on several fronts. For the avid birder keeping a detailed life list, it means another potential check mark in his book. It may have implications on conservation and population dynamics. It might mean absolutely nothing to the birds themselves.
With Tuesday’s discussion of Herring vs. Thayer’s Gulls and today’s Snowy vs. Kentish Plover, this Sunday I will be posting an essay on species, speciation, and why we care. Be sure to check back then as I think it should create an interesting discussion.
Source: Küpper, Clemens, et al. “Kentish versus Snowy Plover: phenotypic and genetic analyses of Charadrius alexandrinus reveal divergence of Eurasian and American subspecies.” The Auk 126.4 (2009): 839-852.