A History of the Birds of New Zealand.
Prion Banksii — (Banks’s Dove Petrel.)
(Banks’s Dove Petrel.)
Prion banksii, Gould, Ann. N. H. xiii. p. 366 (1844).
Prion rossii, Gray, Cat. Brit. Mus. Anseres, p. 165 (1844).
Pachyptila banksi, Smith, Ill. Zool. S. Afr., Birds, pl. lv. (1849).
Procellaria banksii, Schl. Mus. Pays-Bas, Procell. p. 17 (1863).
Pseudoprion banksii, Coues, Proc. Phil. Acad. 1866, p. 166.
Ad. similis P. turturi, sed rostro latiore, pileo saturatiore et caudâ nigro latiùs terminatâ distinguendus.
Adult. Plumage similar to that of P. turtur, but with the crown of the head darker, and a broader terminal band of black on the tail: distinguished by its broader bill. Total length 11·5 inches; wing, from flexure, 9; tail 3·5; bill, along the ridge 1·35, greatest width at the base ·6, from gape to extremity of lower mandible 1·35; tarsus 1·4; middle toe and claw 1·5.
Nestling. Covered with slaty-grey down.
I Was formerly much in doubt about the propriety of retaining the above specific distinction; but a further investigation of the subject has satisfied me that the species is a good one. After a storm on the coast in the month of July I found the Otaki beach strewn with the bodies of the Dove Petrel; and had thus an opportunity of collecting a large number for comparison. Apart from the slight differences of colour, P. banksii has the tail longer and more conical, the wing decidedly longer, and the bill appreciably broader at the base than in P. turtur; besides which the unguis or hooked extremity has a very different form *.
Mr. Gould, in treating of the group, says that Prion ariel is much smaller than P. turtur, and that the pectination of the bill is not discernible when that organ is closed, that P. turtur is the most delicate in colour as well as the most slender and elegant in form of the four species inhabiting the southern ocean, that P. banksii has the bill of a breadth intermediate between that of P. turtur and that of P. vittatus and exhibiting the pectination of the mandibles when closed, and that “there is another and broader-billed species than P. vittatus” not yet described. Captain Hutton, writing on the same subject, observes:—“A regular sequence of the Prions can be formed from P. vittatus to P. ariel; and therefore I do not think it desirable to retain more than three specific names, to mark each end and the centre of the chain; and ariel, as the latest, will have to be omitted. On the New-Zealand coast the intermediate (P. banksii) is much the most common”†. In the last observation I cannot concur; for P. turtur is certainly far more plentiful on every part of the coast that I have visited; and, as already mentioned in treating of the species, numbers are cast ashore after every gale of wind. According to my experience the broad-billed form is far less common than either P. turtur or P. banksii.
* At a Meeting of the Wellington Philosophical Society, held on the 29th January, 1876, five examples of the adult and young of Prion banksii, together with a specimen of the egg, were exhibited; and the Author pointed out the characters which, to his mind, sufficiently distinguished this species from Prion turtur on the one hand, and Prion vittatus on the other. The specimens exhibited were obtained on the small islands off the New-Zealand coast, known as “The Brothers.” (Trans. N.-Z. Inst. vol. viii. p. 197.)
† Cat. Birds of New Zealand, 1871, p. 80.