A History of the Birds of New Zealand.
Mergus Australis. — (Auckland-Island Merganser.)
Mergus australis, Hombr. & Jacq. Ann. des Sci. Nat. 1841, p. 320.
Ad. brunneus, plumis dorsalibus cinereo lavatis: alis caudâque brunneis, tectricibus alarum majoribus nonnullis albo maculatis: secundariis quoque interioribus extùs albo notatis: pileo cristato colloque undique rufe-scenti-brunneis, gutture clariore rufescente: pectore et ábdomine medio albis, schistaceo variis, corporis lateribus saturatè schistaceis, plumis singulis cinereo limbatis: plumis axillaribus purè albis: rostro nigri-canti-brunneo, versus apicem saturatiore: pedibus rufescenti-brunneis.
Adult male. Head, crest (which is two inches long), and the entire neck reddish brown, paler on the throat and lower part of fore neck; entire upper surface dull brownish black, the feathers more or less edged with slaty grey, especially on the shoulders; in place of the speculum there is a broad angular patch of pure white on the secondaries, and a few rounded spots of white on their coverts; breast and middle of abdomen fulvous white varied with grey; sides of body, flanks, and under tail-coverts dark slaty grey, with paler tips, and the long feathers overlapping the thighs slightly mottled with white; axillary plumes pure white; primaries and tail-feathers blackish brown. Bill reddish brown, changing to black on the culmen and at the tips of both mandibles; legs and feet reddish brown. Total length 20·5 inches; wing, from flexure, 7·5; tail 3·5; bill, along the ridge 2·3, along the edge of lower mandible 2·7; tarsus 1·5; middle toe and claw 2·75.
Female. Differs from the male in having no crest, and in the greyer colour of the head and neck.
Of this species, Baron von Hügel writes (Ibis, 1875, p. 392):—“I procured a pair of Mergansers with a few other skins in Invercargill, from a man who had just returned from a surveying trip to the Auckland Islands. He had not even turned the skin after taking it off the body; but as soon as I saw the back through the opening, and felt the beak through the skin of the neck, I knew what I had … . . I have compared this Mergus with the original description of Mergus australis in the ‘Voyage of the Astrolabe’; from it I judge that either the description is a very poor one, or my two birds must belong to a new species. But what agrees well, and made me first think they were an immature pair of birds, is the lower surface of the body, which, instead of being white, as in M. serrator, is of a dull slaty grey, variegated with white bands (the feathers being edged with white). The whole plumage is very dark, approaching black on the back, the crest well formed, and the size, I fancy, considerably smaller than the British Red-breasted Merganser (M. serrator). From the great difference in size and brightness of colouring in bill and feet, I deem them to be male and female; but in plumage there is little difference. The birds were killed the latter end of November last; and I procured them on the 27th of the following month.”
My collection contains a single example (a female), and there is another, of the same sex, in the British Museum. My description of the adult male is taken from the Baron’s specimen in the Cambridge University Museum, which was courteously lent to me by Professor Newton.