6. Black-Browed Mollymawk
(Diomedea melanophris)
Plate 4

Two subspecies:

New Zealand Black-browed Mollymawk (D. melanophris impavida)

Black-browed Mollymawk (D. melanophris melanophris)

The above two subspecies are difficult to distinguish from each other at sea. At very close range, however, both their differing eye (iris) colours and amounts of black feathering in the vicinity of the eye are discernible (see below).

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Field Characters: 230/90. A medium-sized mollymawk, generally resembling a large Black-backed Gull in colour. Head and body including rump and tail coverts white, these contrasting sharply with the black mantle, upperwings and tail. Conspicuous black eyebrow. Underwing broadly and irregularly margined with black, particularly along the leading edge. The black anterior margin is broadest at the elbow, where it forms a conspicuous wedge. The inner edge of this margin is often irregular and not sharply demarcated from the white underwing coverts. The amount of black pigmentation on the underwing varies between individuals. Juvenile birds have a white head with a grey wash on the nape and a variable, incomplete, grey breast band. The underwing is dark with only a pale central flush (Fig. 6c, Pl. 4).

Bill deep yellow with rosy-pink tip in adult birds. In juveniles it is dark olive brown with black tip. The feet are bluish-white.

The New Zealand race (impavida) in its adult stage is characterised by a light honey coloured iris and a more prominent amount of black feathering about the eye, especially on the lores. In the nominate race (melanophris) the iris is dark brown, and there is noticeably less black in front of the eye. The distinction is readily made at close range. The iris of juvenile birds is dark brown in both races.

Flight soaring and swooping. Readily follows ships.

The New Zealand race breeds on Antipodes and Campbell Islands, while the nominate race breeds locally on Macquarie Island and has circumpolar distribution. Both subspecies occur commonly in New Zealand waters.