THALASSIDROMA WILSONII, Bonap. 
Wilson’s Storm Petrel. 
Pr ocellar ia Wilsonii, Bonap. in Journ. of Nat. Sci. of Philad., vol. iii. p. 231. pi. ix. — Orel’s Reprint of Wils. Am. 
Orn., p. 94. — Steph. Cont. of Shaw’s Gen. Zool., vol. xiii. p. 224.- — Zool. Journ. vol. i. p. 425. 
Thalassidroma Wilsonii , Bonap. Synopsis of the Birds of the United States, p. 367.— Jard. Edit, of Wilson’s Am. 
Orn., vol. ii. p. 381. pi. lx. fig. 6. — Audubon, Birds of Am., pi. cclxx. fig. 1 . — lb. Orn. Bio., vol. iii. 
p. 486. 
Procellaria pelagica, Wils. Am. Orn., vol. vii. p. 90. pi. lx. fig. 6. 
Wilson’s Stormy Petrel, Nuttall, Manual, vol. ii. p. 322. 
Oceanites Wilsonii, Keys, et Bl. — G. R. Gray, List of Gen. of Birds, 2nd Edit. p. 99. 
Thalassidroma Oceanica, Kuhl, Monog., tab. 10. fig. 1.— List of Birds in Brit. Mus. Coll., Part iii. p. 161. 
I possess a specimen of this bird which was sent me by his Excellency Governor Grey, who killed it in the 
South Atlantic. It is also one of the most abundant species of the genus inhabiting - the Australian seas : I 
observed it in great numbers within sight of the shores of Van Diemen’s Land, and shot and preserved 
several specimens during my passage from Sydney to Hobart Town in April 1839; I also encountered it in 
the following year in the seas between Sydney and New Zealand, while on my passage towards Cape Horn. 
On carefully comparing these with others from the North Atlantic no specific difference was observable, 
hut the former were a trifle larger than the latter. 
On my voyage to Australia I encountered the Thalassidroma Wilsonii within a day’s sail of the Land’s End, 
and continued to observe it from the deck of the vessel from thence across the Bay of Biscay to Madeira, 
its numbers gradually lessening as we approached the tropics, within which it was never seen. May we not 
therefore infer that in the same zone of both hemispheres this species finds a natural asylum, if the slight 
difference in size I have mentioned be not of sufficient importance to warrant their being considered as 
distinct ? Certainly! am not aware of any other species of Petrel being found on both sides of the equator. 
It is exceedingly active when flying, its wings being kept fully expanded ; it also makes considerable use 
of its feet, patting and leaping over the surface of the water, with its wings extended upwards and its head 
inclined downwards, to gather any food that may present itself. Its usual diet consists of mollusca, small 
fish, Crustacea, and any kind of greasy substance that may be floating on the water. 
The sexes are so precisely similar that they can only be distinguished by dissection. 
The head, neck, back, wings and breast sooty black, the wing-coverts passing into pale brown at the ex- 
tremity ; primaries and tail black ; upper and lateral portions of the under tail-coverts white ; irides dark 
brown ; bill and feet black ; webs yellow for three parts of their length from the base. 
The figures are somewhat smaller than the natural size. 
