A History of the Birds of New Zealand.
Phalacrocorax Colensoi. — (Auckland-Island Shag.)
Ad. similis P. carunculato, sed conspicuè minor: haud carunculatus: dorso postico minimè plagâ albâ notato.
Adult. Crown of the head, shoulders, feathers composing the mantle, wing-coverts, and scapulars bronzy brown, with a green gloas in certain lights; hind part and sides of neck, lower portion of back, rump, and thighs blue-black with a fine metallic gloss; the median wing-coverts white, forming a broad alar bar extending nearly the whole length of the cubitus; a line from the chin, widening into a broad stripe down the fore neck, and the whole of the underparts pure white; quills and tail-feathers and the under surface of wings blackish brown; bill yellowish brown; legs and feet orange-yellow. Extreme length 28 inches; wing, from flexure, 10·5; tail 6; bill, along the ridge 2·5, along the edge of lower mandible 3; tarsus 2; longest toe and claw 4·25.
Young. Differs from the adult in having the whole of the upper parts blackish brown, glossed with green only on the mantle, lower part of back, and rump, the blue metallic gloss being entirely wanting; the crown of the head, back and sides of the neck, interscapular region, and upper surface of wings paler brown; the median wing-coverts and the scapulars fading to brownish white at the tips, but without any appearance of an alar bar; remiges and tail-feathers dark brown, the latter largely margined on both webs with brownish white; the streak of white down the fore neck interrupted in its middle portion by the dark colour which spreads across in a cloudy pale brown wash. Bill dark yellow, brownish on the ridge; legs and feet dull orange.
Obs. It is clear that the states of plumage are as described, because my adult bird betrays vestiges of the adolescent garb in the wings and tail, the moult not having been quite completed.
This Shag is readily distinguishable from P. carunculatus by its much smaller size, by its smooth face, and by the absence of the white dorsal marks. It has less of the green metallic gloss on the head and neck, the green on the mantle is duller, and the back, rump, and thighs are decidedly bluer than in the last-named species. In P. carunculatus the pointed stripe of white feathers between the crura of the lower mandible widens rapidly on the throat and fore neck, occupying a larger surface than the dark plumage before reaching the breast; in the present species it presents only a broad stripe down the centre of the fore neck, which spreads out abruptly just above the breast. The white alar bar, although narrow, is far more conspicuous than in P. carunculatus, being fully six inches in length.
The only two specimens in my possession—the adult and young described above—were received by me from the Auckland Islands in 1885, having been collected by Mr. Burton, of the Colonial Museum, who found hundreds of these Shags frequenting the rocks, and collected twenty or more specimens, many of which I examined. One of these (marked ♀), apparently a younger bird, had the colours much duller than in my example.
In the British Museum there are two examples (in moulting condition) obtained by Baron A. von Hügel at the Bluff, in the provincial district of Southland.
Having to select a distinguishing name for this species, I have much pleasure in dedicating it to my friend the Rev. William Colenso, F.R.S., who, as I have already shown on page 152, recorded his observations on the Shags inhabiting New Zealand nearly fifty years ago, and who has been ever since an active contributor to the scientific literature of his adopted country.