Before describing the habits of this bird, I think it necessary to speak of the three distinct species which are at times found near our coasts, and of which I have found two breeding within the Union. The present species is the largest; that named after WILSON the next in size; and the one called the Stormy Petrel the least. Until I had met with the whole of these species near our coast, I, like others, thought that the last mentioned kept nearer to Europe than it in reality does at certain seasons.

In August 1831, I was on board of the American packet-ship Columbia, commanded by my friend JOSEPH C. DELANO, Esq., who had promised that, in case of a calm occurring, he would allow me to have a boat manned to go in search of birds. The day is not given, because I never keep a journal while crossing the Atlantic; but as I had left England on the first of the month, and was then on the banks of Newfoundland, it must have been towards the latter part of it, when the weather suddenly became quite calm and beautiful. "Mother Carey's Chickens" were by hundreds around the noble ship, and although ill in consequence of the sickness which never leaves me at sea, I asked for a boat and some hands to row me about for an hour or so. This was granted, guns and ammunition were placed in the yawl, and my assistant, Mr. HENRY WARD of London, an officer, and two sailors, accompanied me. We had three guns, which were alternately loaded and handed to me. In the course of about an hour, twenty-five or thirty Petrels were shot, together with some Fulmars. Had you been looking on, you might perhaps have laughed at me on seeing that the moment after I fired, I was obliged to lean over the side of the bark to relieve myself from the distressing state of my stomach. On returning to the ship, my companions nimbly ascended the chains; but although when on land I am pretty firm and active, I was now quite unfit for service, and therefore was hoisted in a chair. Once on deck, I laid myself down on a mattress, my wife attended to me, and I gradually became relieved, as the ship stood, to use the words of my kind captain, "as still as if on the stocks." There were the dead birds nicely arranged on a board by my side; the wounded ones were placed in a cage, and I began to examine them all with care. To my great surprise, I found among them all the three species mentioned above. Sixteen of these birds were beautifully prepared by Mr. WARD, and the rest were placed in spirits, after I had made correct outlines of each species, and taken their exact dimensions and weight. The drawings, however, I was unable to finish on account of the giddiness, which seldom leaves me while at sea. The calm continued the whole of the next day, and, laying myself down on the top of the round-house, I had ample opportunities of observing the habits of the three species, while thus at a distance from land.

My esteemed friend the Prince of MUSIGNANO has stated that the Forked-tailed Petrel is less numerous near the American coast than the species named after WILSON. It is true that it rarely goes so far south, but in the vicinity of Massachusetts, and from thence to Newfoundland, it is by far the most abundant of the two; and it breeds on all suitable places from the Islands of Mount Desert to the last mentioned country.

The species of this genus with which I am acquainted all ramble over the seas, both by night and by day, until the breeding season commences, when they remain in their burrows, under rocks, or in their fissures, until towards sunset, when they start off in search of food, returning to their mates or young in the morning, and feeding them then. I feel pretty confident that these birds, like Owls, can hold out against hunger for many hours, and are satisfied with one abundant meal in the day. WILSON was of a different opinion, but I believe he never found these birds breeding.

The Forked-tailed Petrel emits its notes night and day, and at not very long intervals; although it is less noisy than Wilson's Petrel. They resemble the syllables pewr-wit, pewr-wit. Its flight differs from that of the other two species, it being performed in broader wheelings, and with firmer flappings, in which respect it resembles that of the Night Hawk, Chordeiles virginianus, while that bird is passing low over the meadows or the waters. It is more shy than the other species, and when it wheels off after having approached the stern of a ship, its wanderings are much more extended before it returns. I have never seen it fly close around a vessel, as the others are in the habit of doing, especially at the approach of night; nor do I think that it ever alights on the rigging of ships, but spends the hours of darkness either on the water, or on low rocks or islands. It also less frequently alights on the water, or pats it with its feet, probably on account of the shortness of its legs, although it frequently allows them to hang down. In this it resembles the Thalassidroma pelagica, and Wilson's Petrel has a similar habit during calm weather. I have seen all the three species immerse their head into the water, to seize their food, and sometimes keep it longer under than I had expected.

About the first of June, the species separate, collect in numbers, and return to their breeding places. I state so from the report of persons on whose testimony I can rely, and who have assured me that, like the Guillemots, they revisit their haunts each spring for years in succession. They now fly in front of the high rocks, in the manner of our Purple Martin when it first arrives at its well known box, passing and repassing a thousand times in the day, enter their dark and narrow mansions, or stand in the passage, and emit their cries, as the bird just mentioned is wont to do on similar occasions. Now they alight on some broad shelf, and walk as if about to fill down, but with considerable ease, and at times with rapidity. Now and then the mated birds approach each other, and, I believe, disgorge some food into each other's mouths, although I am not absolutely certain that they do so, having only observed them at such times by means of a glass. They collect grasses and pebbles, of which they form a flat nest, on which a single white egg is deposited, which measures an inch and a quarter in length, by seven-eighths in breadth, is nearly equally rounded at both ends, and looks very large for the size of the bird. When boiled, it has a musky smell, but is palatable. When you pass close to the rocks in which they are, you easily hear their shrill querulous notes; but the report of a gun silences them at once, and induces those on the ledges to betake themselves to their holes.

The Forked-tailed Petrel, like the other species, feeds chiefly on floating mollusca, small fishes, crustacea, which they pick up among the floating sea-weeds, and greasy substances, which they occasionally find around fishing-boats or ships out at sea. When seized in the hand, it ejects an oily fluid through the tubular nostrils, and sometimes disgorges a quantity of food. I could not prevail on any of those which I had caught to take food.

FORK-TAILED STORMY PETREL, Thalassidroma Leachii, Nutt. Man., vol. ii.p. 326.

FORKED-TAILED PETREL, Thalassidroma Leachii, Aud. Orn. Biog., vol. iii.p. 434.

Male, 8, 18 1/2.

Common on the Banks of Newfoundland, and at times off the coast of Massachusetts, Maine, and Nova Scotia. Breeds on the shores of Baffin's Bay.

Adult Male.

Bill shorter than the head, slender, straight, with the tips curved, as broad as high at the base, extremely compressed at the end. Upper mandible with the nostrils forming a tube on its ridge at the base, beyond which the dorsal line is for a short space straight, then decurved, the ridge narrow and separated from the convex sides by a narrow groove, the edges sharp, inflected, the tip compressed, incurved. Lower mandible with the angle rather long, narrow and pointed, the dorsal line beyond it decurved, the sides erect, the edges sharp, the tip decurved.

Head of ordinary size, roundish, anteriorly narrowed. Neck short. Body rather slender. Feet rather long, slender; tibia bare at its lower part; tarsus slender, reticulate all round. Hind toe minute, with a conical claw; anterior toes of moderate length, slender, scutellate above, connected by striated webs with concave margins; the third and fourth toes longest, and about equal. Claws slender, arched, compressed, acute.

Plumage very soft, blended, the feathers distinct only on the wings, which are very long; primary quills tapering but rounded, the outer four a little incurved at their extremities, the second longest, the third almost equal, the first and fourth about the same length, the rest rapidly graduated; outer secondaries incurved, obliquely rounded; inner longer, tapering, straight. Tail deeply forked, of twelve broad, rounded feathers.

Bill and feet black. Iris dark brown. The general colour of the plumage is dark greyish-brown, the quills and tail brownish-black, the smaller wing-coverts and inner secondaries light greyish-brown; the rump, sides of the abdomen, and exterior lower tail-coverts, white.

Length to end of tail 8 inches, to end of wings 8 1/2; extent of wings 18 1/2; wing from flexure 6 1/2; tail 3; bill along the back 8/12, along the edge of lower mandible 10/12; tarsus 1; middle toe 10/12, its claw (3 1/2)/12. Weight 1 5/8 oz.

The Female is exactly similar to the male.