 It was among the birds noted by James Cook in January 1775, on the occasion of the first recorded landing on South Georgia, and was formerly considered a full species.The duck has long been recognised as a distinct taxon, with its affinities previously considered to be with the teals.Robert Cushman Murphy was the first to demonstrate that it is a pintail, its closest relatives the yellow-billed pintails of South America (now split as the Chilean pintail "A. g. spinicauda" and the extinct Niceforo's pintail "A. g. niceforoi"), though he retained it as a full species for its isolated distribution and its 16 (rather than 14) rectrices, or tail feathers.