The Pomarine Jager


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Birds of America

By John James Audubon, F. R. SS. L. & E.

VOLUME VII.

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Family
Genus

THE POMARINE JAGER.
[Pomarine Jaeger.]

LESTRIS POMARINUS, Temm.
[Stercorarius pomarinus.]

PLATE CCCCLI.--FEMALE.

This bird I never had an opportunity of examining until I visited Labrador; nor am I able to give you much information respecting its habits as obtained by my own observation, and therefore I shall take the liberty of adding to my description such notices as I may judge interesting, taken from the works of authors who, having seen for themselves, are entitled to credit.

While sailing towards the harbour of Little Macatina, and yet about forty miles distant from it, although not far from the shore, we observed a bird of this species approaching the vessel. It flew in the manner of the Pigeon Hawk, to my account of which I may refer you, alighted on the water like a Gull, and fed on some codfish's liver that had been thrown overboard for the purpose of attracting it. Several small Petrels joined it, but it did not come within shot, and the sea was too rough for even our whale-boat. On the 30th of July the young men of my party brought me a fine adult female, in excellent order, from which I drew the figure in the plate. A few days after we experienced a very heavy gale while in the harbour of Bras d'Or, during the continuance of which twenty or thirty of these birds came about us, although none of them approached within shot, and no boat could have ridden the furious waves without imminent danger. On that occasion, however, I was enabled to observe some of their habits. They flew wildly about, yet with much grace, moving rapidly to and fro, now struggling against the blast, now bearing off and drifting to a considerable distance. Many Gulls were flying about, having also made for the harbour to obtain some shelter from the storm. The Lestris chased the smaller species with effect, but never approached the Great Black-backed Gulls, nor even their young, which were also flying with the rest. The Kittiwakes and the Ring-billed Gulls were the species which we saw them attack, although they did not procure much food from them, the weather being such that they could not fish. They were therefore contented, as was the Lestris, with the fishes that had been thrown on shore. At times the Jagers would ramble over the land, flying close upon the rocks, and proceeding at a rapid rate even against the wind. They remained in our neighbourhood until the tempest abated, when they went off to sea, and I saw no more of them until we reached St. George's Bay in Newfoundland.

There, on a squally afternoon, two or three of them were observed flying around, but keeping at such a distance that we could not shoot any of them. The following day, after setting sail, we encountered a heavy gale, which, although foretold by me from the appearance of the birds in the harbour, our good captain would not believe as likely to happen. We were obliged to lie-to, and were tossed about for three nights and days, but escaped with little other damage than the loss of a pet Gull, which was washed overboard.

On our return to Eastport, Captain EMERY told me that he had seen a great number of these Jagers near Cape Sable; and at Halifax, in Nova Scotia, I was assured that they breed on Sable Island, which is sixty or seventy miles distant from the coast. I never observed one of these birds along the shores of the United States, although some of the genus go as far south in winter as the Gulf of Mexico.

Nothing is known with certainty respecting the changes which this species undergoes as it advances toward maturity. Captain JAMES CLARK Ross, R. N., has informed me that a nest containing two eggs was found by him near Fury Point, close by the edge of a small lake. I have no doubt that this bird breeds in Labrador, as the female which I obtained in July appeared as if it had young at the time.

My friend Mr. SELBY states that he is not aware that an adult bird has yet been killed in Britain. M. TEMMINCK says it forms a rude nest of grass and moss, which is placed on a tuft in the marshes, or on a rock, and lays two or three very pointed eggs, of a greyish-olive colour, marked with a few blackish spots. Dr. RICHARDSON has the following notice respecting it in the Fauna Boreali-Americana:--"The Pomarine Jager or Gull-hunter is not uncommon in the Arctic seas and northern outlets of Hudson's Bay, where it subsists on putrid fish and other animal substances thrown up by the sea, and also on the matters which the Gulls disgorge when pursued by it. It retires from the north in the winter, and makes its first appearance at Hudson's Bay in May, coming in from seaward."

LESTRIS POMARINA, Bonap. Syn., p. 364.
LESTRIS POMARINA, Pomarine Jager, Swains. and Rich. F. Bor. Amer.,vol. ii. p. 429.
POMARINE JAGER, Nutt. Man., vol. ii. p. 315.

POMARINE JAGER, Lestris pomarinus, Aud. Orn. Biog., vol. iii. p. 396;vol. v. p. 643.

Female, 20 1/4, 48.

From Massachusetts northward. Seen in Labrador. Breeds in high northern latitudes.

Adult Female.

Bill shorter than the head, strong, slightly compressed, straight, the tip curved. Upper mandible with the dorsal line nearly straight, toward the tip curved, the ridge broad and convex with a slight central depression, the sides convex, the edges sharp and inflected, the tip compressed, rather rounded but sharp. Nasal groove long, narrow, curved; nostrils in its fore part, medial, lateral, longitudinal, broad before, extremely narrow behind, open and pervious. Lower mandible with the angle long and narrow, a slight prominence at its extremity, beyond which the dorsal line is slightly concave, the sides erect, and slightly convex, the edges sharp and inflected, the tip obliquely truncate.

Head rather large. Neck of moderate length. Body rather full. Feet of moderate length, rather slender; tibia bare at its lower part, and rough all round with small convex scales; tarsus compressed behind, anteriorly covered with decurved scutella, the sides reticulated, the hind part rough with small pointed scales; hind toe extremely small and elevated, the fore toes of moderate size, connected by reticulated webs, which have their margins convex; the third toe longest, the fourth nearly as long, all scutellate above. Claws strong, curved, very acute, compressed, that of third toe with a sharp inner edge.

The plumage in general is close, elastic, soft and blended; the feathers on the back and wings rather compact and distinct. Wings very long, rather broad, pointed; primary quills tapering and rounded, the first longest, the rest rapidly graduated; secondary rather short, rounded. Tail of moderate length, the feathers, which are twelve, are broad and rounded, the two middle an inch longer than the next.

Bill blackish-brown at the end, dingy-yellow towards the base. Iris brown. Tibia, toes, webs, and lower half of tarsus black, the upper half light blue; claws black. Upper part and sides of the head anteriorly brownish-black; upper part of neck all round yellowish-white; the rest of the neck white, barred with brownish-black, each feather having two transverse bands of that colour; breast white; sides, abdomen and lower tail-coverts white, barred with brownish-black, as are the upper tail-coverts. Back and wings brownish-black; primary quills of the same colour, white on the inner webs towards the base, as are the secondaries and tail-feathers, lower surface of wings mottled and barred with white and dusky.

Length to end of tail 20 1/4 inches, to end of wings 20 1/4, to end of claws 19 1/4; extent of wings 48; wing from flexure 14; tail 6 2/12; bill along the back 1 9/12, along the edge of lower mandible 2 1/2; tarsus 2 1/12; middle toe 1 9/12, its claw 8/12. Weight 1 1/2 lbs.

Female, from Dr. T. M. BREWER. The mouth rather wide, 1 inch 2 twelfths across; the palate flat, with two longitudinal papillate ridges, the space between which and the palatal slit is also covered with papillae; anteriorly, on the mandible, are three ridges; posterior aperture of the nares oblongo-linear, with its margins papillate; the lower mandible dilatable, as in the Gulls. Tongue 1 inch long, emarginate and papillate at the base, broadly channelled above, contracted and induplicate toward the end, horny beneath, and thin-edged, with the point slit to the depth of 1 1/2 twelfths. Lobes of the liver very unequal, the right 2 1/4 inches long, the left 1 inch 10 twelfths; gall-bladder oblong, 7 1/2 twelfths long, 3 twelfths broad. The stomach, Fig. 1 [c d], is small, 1 inch 2 twelfths long, 1 inch in breadth; its lateral muscles thin; the epithelium thin, longitudinally rugous, of a reddish colour. The proventricular glands extremely small, roundish, forming a belt 7 twelfths in width. Intestine, [f g h l m], 24 1/2 inches long, 6 twelfths wide at the top, but contracting to 4 twelfths; it forms 7 curves; the coeca, [j k], 1 inch 10 twelfths in breadth. Trachea 5 inches long, from 3 1/2 twelfths to 2 1/2 twelfths long, for 8 twelfths their width is 1 twelfth, afterwards 2 1/2 twelfths, diminishing to 1 3/4 twelfths, the extremity blunt; rectum 2 inches 3 twelfths long, for 1 inch 4 twelfths in width, then enlarging into an oblong cloaca 10 twelfths in breadth; considerably flattened; the rings 98, unossified, of the same structure as in the Gulls. Bronchi rather wide, of 20 half rings. Muscles as in the Gulls.

The digestive organs of this bird differ from those of the Gulls only in having the coeca much more elongated; the cloaca oblong, instead of being globular, and the stomach less muscular. The tongue differs greatly from that of either the Gulls or Terns.

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