To my learned friend the Prince of Musignano, the scientific world is indebted for a Memoir on Petrels, in which he has clearly shewn the specific differences of the three species mentioned above, of which he has also given figures, as well as those of the bills and feet nearly of the natural size. But the artist who drew these birds for him, or the engraver, committed an error in representing the present bird as the largest of the three.
Wilson’s Petrel breeds on some small islands situated off the southern extremity of Nova Scotia, and called “Mud Islands,” but which are formed of sand and light earth, scantily covered with grass. Thither the birds resort in great numbers, about the beginning of June, and form burrows of the depth of two or two and a half feet, in the bottom of which is laid a single white egg, a few bits of dry grass, scarcely deserving the name of a nest, having been placed for its reception. The egg measures an inch and a half in length, by seven-eighths of an inch in breadth, is almost equally rounded at both ends, and has a pure white colour. These Petrels copulate on the water, in the same manner as the Hyperborean Phalarope. By the beginning of August the young follow their parents to sea, and are then scarcely distinguishable from them. During incubation, they remain in the burrows, or at their entrance, rarely going to seek for food before the dusk.
On wing this species is more lively than the Forked-tailed, but less so than the Common Stormy Petrel. It keeps its wings nearly at right angles with its body, and makes considerable use of its feet, particularly during calm weather, when it at times hops or leaps for several feet, or pats the water, whilst its wings are extended upwards with a fluttering motion, and it inclines its head downwards to pick up its food from the water, and I have observed it immerse the whole head beneath the surface, to seize on small fishes, in which it generally succeeded. It can walk pretty well on the deck of a vessel, or any other flat surface, and rise from it without much difficulty. Its notes are different from that of the Forked-tailed Petrel, and resembles the syllables kee-re-kee kee. They are more frequently emitted at night than by day. I never could ascertain whether or not these birds alight on the rigging at night, but my opinion is that they do not, for the sailors, to whom I had offered premiums for catching some of them, told me that although they flew about them while aloft, they could not see one standing anywhere.
In my journal written on board the packet ship Columbia, commanded by my worthy friend Joseph Delano, Esq., I find the following memorandums: “Wilson’s Petrel was first seen, this voyage, about two hundred miles from England, and alone until we reached the middle of the Atlantic, when the Forked-tailed came in sight, after which the latter was most plentiful, and the pelagica by far the least numerous.” During my several visits to the coasts of the Floridas, I saw scarcely any of these birds in the course of several months spent there, but I found them pretty abundant on returning towards Charleston. This species, like the others, feeds on mollusca, small fishes, crustacea, marine plants, excrements of cetaceous animals; and the greasy substances thrown from vessels. When caught, they squirt an oily substance through the nostrils, and often disgorge the same. The sexes are similar in their external appearance.
Thalassidroma Wilsonii, Ch. Bonaparte, Synops. of Birds of the United States, p. 367.
Stormy Petrel, Procellaria pelagica, Wils. Amer. Ornith. vol. vii. p. 90. pl. 60.
Procellaria Wilsonii, Ch. Bonaparte, Journ. Acad. Phil. vol. vi. p. 231. pl. 9.
Wilson’s Stormy Petrel, Nuttall, Manual, vol. ii. p. 322.
Adult Male. Plate CCLXX. Fig. 1.
Bill shorter than the head, slender, straight, with the tips curved, as broad as high at the base, compressed towards the end. Upper mandible with the nostrils forming a tube at the base, beyond which, for a short space, the dorsal line is straight, then decurved, the ridge narrow and separated from the sides by a narrow groove, the edges sharp, inflected, the tip compressed obliquely deflected. Lower mandible with the angle rather long, narrow and pointed, the dorsal line beyond it very slightly concave and decurved, the sides erect, the edges sharp, the dip slightly decurved.