Ordee TUBINAEES.] 
[Fam. PEOCELLARIID^. 
PEION AEIEL 
(GOULD’S DOVE PETREL.) 
Prion ariel, Gould, Ann. N. H. xiii. p. 366 (1 844). 
Procellaria ariel, Schl. Mus. Pays-Bas, Procell. p. 18 (1863). 
Pseudoprion ariel. Cones, Proc. Phil. Acad. 1866, p. 166. 
Ad. similis P. turturi, sed minor. 
Adult. Similar in plumage to Prion turtur, hut smaller in all its proportions. Total length 10 inches j wing, 
from flexure, 6'5 j tail 2-25 ; hill, along the ridge -75, along the edge of lower mandihle 1 ; tarsus 1 ■, middle 
toe and claw 1'5. 
This is the smallest of the Prions. On the 13th February, 1881, I picked up two storm-killed 
specimens on the beach near Otaki ; and on the same day I caught with my hand another that was 
fluttering on the wing evidently much exhausted by its efforts to preserve life. This was a female, 
and from being storm-driven the stomach was empty. It is undistinguishable from P. turtur except 
by its smaller size, and I am in doubt about the propriety of keeping it separate *. 
On one occasion, when nearly thirty miles from land, about sundown, just as the sky had become 
overcast, I observed large flights of the Dove Petrel — sometimes in close communities, sometimes 
more widely scattered — all coming in the same direction and taking a south-west course. This 
constant stream of passengers was kept up till dark, and probably much later ; but during the time 
they were visible some tens of thousands must have passed by us, all of them, under some 
common impulse, making for mid-ocean. Long after dark, I noticed a flock of them hunting in 
company and very near the surface of the water on our weather port. 
A friend who visited Mutton Island, towards the end of December, assures me that he found 
numbers of young Dove Petrels nesting in holes burrowed in the layers of guano, and looking like 
little balls of bluish-grey down, but he saw no old birds during his stay there of several hours ; and 
it is rather a curious circumstance that the nests were all on the southern side of the island, probably 
on account of its more sheltered position. 
Mr. Sharpe, adopting Latham’s view, has suggested (Zool. Kerg. Island, p. 139) that the differ- 
ence in the bill which characterizes the various species of Prion may be only a sexual character. 
But I think I have placed that point beyond all question. The twenty specimens mentioned on 
page 210 were carefully dissected by me, with the following results : — Of Prion hanicsii there 
were four males and four females ; of P. turtur there were seven males and five females. In some 
cases, owing to the state of the reproductive organs at that season of the year (first week in July), I 
was unable to determine the sex with absolute certainty. In others, however, the testes were suffici- 
ently conspicuous ; whilst in two females of P. turtur and in one of P. hanicsii I was able to detect a 
bunch of undeveloped eggs. The examination in this respect was therefore conclusive. 
* Mr. Sharpe says (“ Zool. of Kerg. Island,” Phil. Trans. E. S. p. 1 01) that he considers Prion arid “ nothing but the 3 'oung, 
of P. turtur', ” hut the bird described above was a fullj' matured one. 
