• Puffinus assimilis, Gould, P. Z. S. 1837, p. 186.

• Procellaria nugax, Solander, MS. (Bonap. Consp. Av. ii. 1856, p. 205).

• Puffinus assimilis, Salvin, Ibis, 1888, p. 357.

Ad. similia P. obscuro, sed minor et obscurior, plumis corporis superioris cinerasceate marginatis: subalaribus et subcaudalibus omninò albis.

Adult. Very similar in appearance to P. obscurus, but smaller. There is less brown in the dark colouring of the upper surface, the prevailing colour being slaty black, the edges of the feathers having a bluish-grey or ashy tinge; the blending of colours on the sides of the neck is softer; the lining of the wings is pure white over the entire surface, as are also the under tail-coverts; and the wing-feathers instead of being uniform slaty brown are white on their inner webs, shading into grey towards the tips. Irides black; bill brownish black. Total length 12·5 inches; wing, from flexure, 7·75; tail 2·5; bill, along the ridge 1·15, along the edge of lower mandible 1·25; tarsus 1·5; middle toe and claw 2.

Nestling. Taken from the nest on Little Barrier, 6th Nov. Covered with, long, soft, dark grey down, paler on the underparts, and becoming whitish on the crop; throat bare, with minute white tufts of down just appearing.

Obs. A specimen of P. assimilis, obtained by Mr. John Macgillivray on Raoul Island (Kermadec group), and now in the British-Museum collection, is somewhat smaller in all its dimensions, but precisely like our bird in all other respects—coloration of plumage, soft parts, &c.

Mr. Reischek informs me that he found this species on the Chicken Island in December 1880. He discovered adult birds with their unhatched egg and the tuatara lizard (Sphenodonpunctatum) all in the same burrow, and sometimes young birds associated with the reptile, but occupying separate chambers. He writes:—“I found them very plentiful at this season on the south-eastern side of this island. On the smaller island I met with them again, but there were only a few of them there. I noticed that they ventured further inland for the purpose of breeding than Puffinus gavia. They commence their nesting-operations about the end of October, and their habits at this season are in no respects different from those of the latter species.”

Like Majaqueus parkinsoni and Æstrelata, cookii, it resorts, on the Little Barrier, to the wooded parts of the island, selecting always a high elevation and generally a little way inland. During the breeding-season the male bird habitually goes out to sea during the day, returning at night and hovering over the island with much clamour, but observing a discreet silence on approaching its nest.

Reischek informs me that in bright moonlight nights he has found them sitting in the trees uttering their cry of ha-kwa-kwa. He obtained an egg on the 17th October which was nearly hatched out, and met with nestlings three weeks later.

The egg of this Petrel is ovoido-conical in form, measures 2·2 inches in length by 1·4 in breadth, and when fresh is perfectly white.