Having taken six specimens of the Marsh Tern of America to the British Museum, and minutely compared them in all their details with the specimens of the Gull-billed Tern which formed part of the collection of Colonel MONTAGU, and were procured in the south of England, I found them to agree so perfectly that no doubt remained with me of the identity of the bird loosely described by WILSON with that first distinguished by the English ornithologist.
I have shot several Marsh Terns out of the same flock, in the early part of spring, when the youngest must therefore have been nearly a year old, and found them all equally perfect and beautiful in their plumage, but differing considerably in the length of their bills, tarsi, toes, and wings, insomuch that a person bent on forming new species might easily gratify his inclination by founding "specific characters" on differences, which, however, would be merely those of males and females of different ages. With me the habits of birds, when minutely and faithfully described, go much farther to establish the identity of individuals found in the different parts of the globe, than the best and closest descriptions of prepared skins. Colonel MONTAGU informs us that the Gull-billed Tern, Sterna anglica, resorts by preference to lakes and rivers of the interior; and Mr. SELBY states, that "on the European continent it frequents the marshes and the lakes of Neusidel and Platten in Hungary." The same naturalist also says: "Upon investigating specimens from North America, I feel no hesitation in considering the Marsh Tern of WILSON's North American Ornithology to be the same bird, although Mr. ORD (in his eighth volume of that work) is inclined to regard it as distinct, in consequence of some difference between the length of the bill and tarsi, as expressed in a drawing of Sterna aranea that he examined, and the proportions of those parts in the first species as given by MONTAGU and TEMMINCK."
Now, reader, allow me to lay before you an account of the habits of the Marsh Tern, a figure of an adult individual selected from among three shot within a few hours of each other, and the measurements of several recent birds. You may then judge whether or not our bird is that described by MONTAGU.
The Marsh Tern is pretty abundant about the salt-marshes of the mouths of the Mississippi in the beginning of April; and by following the shores of the Gulf of Mexico, you will find that it comes to us from beyond Texas, as many make their appearance along that coast in a straggling manner during spring, there being seldom more than half a dozen together, and generally only two. Their journeys are performed over the waters of the sea, a few hundred yards from the shore; and when in want of food, they diverge from their ordinary course, and ranging over the land satisfy their hunger, when they resume their route.
Excepting the Cayenne Tern, I know no American species that has so powerful a flight as the present. To this power is added an elegant lightness that renders it most conspicuous and pleasing during the love season. Then "the happy pair" are seen to rise in elegant-circling sweeps, almost in the manner of Hawks, and only a few feet apart, until they attain a height of about two hundred yards, when they come close together, and then glide with extended pinions through the air, the male over the female, both emitting tender and plaintive notes, while they vary their evolutions at the same height for five or six minutes. After this the winged lovers separate, plunge towards the earth with wonderful rapidity, resume their ordinary notes, and seek for food in concert. The usual cry of these birds is rough, sharp, distinguishable at a considerable distance, and often repeated as if to assure each other that they are near. When an accident happens to the female during the breeding season, her mate manifests a most affectionate concern; but the female in such a case acts differently. On shooting several males on various occasions, whether they were killed outright, or fell wounded on the earth or the water, I observed that the female would only take a round as she rose above the reach of shot, and move off at once to some considerable distance; but when the female dropped, if on the water, the male would plunge head-long toward her, and alighting by her side, would do all in his power to aid her in swimming or flying off. If she fell on the ground, he would alight there, and exhibit the same marks of anxious care, thus affording to the gunner the best possible opportunity of destroying him.
The Marsh Tern swims buoyantly but not swiftly, and when wounded does not attempt to dive, but when taken in the hand bites rather severely, though without uttering cries, in which latter respect it differs from the other species. Whilst travelling or inspecting the pools of the marshes, or the bayous intersecting them, it passes at a considerable height with quickly repeated movements of the wings, and when looking for food, it darts through the air and slides toward the waters, as if about to dive for fish. I have observed them coming over large mud-flats and marshes to bayous, apparently for the latter purpose; but I believe that these birds never immerse themselves in the water, as other Terns are wont to do; nor do I think that they procure fish, as, on examining a number of individuals near the mouths of the Mississippi, in Texas, and at Great Egg Harbour, I never found any other food in their stomachs than insects of various kinds, including coleoptera, which were unknown to me. In many instances, when near the places first mentioned, my friend EDWARD HARRIS and myself saw them catching insects on wing over a small pond of almost putrid water, the surface of which was entirely covered with a thick green layer of water-plants. The same manner of procuring food was observed over the dry land at Barataria, where they seized insects by diving as it were close to the ground and again rising to a considerable height. Their plunges were performed with great velocity, generally by the males and females alternately. In two or three instances, I have seen some of these birds plunge towards the water at sea, but always close on the shore, and have supposed that when insects are scarce on the land, particularly during their migration southward, they may be forced to feed upon fish; but this is merely a supposition, in support of which I have no fact to offer. I took upon what has been said as to their feeding along the sea-shores "almost exclusively on strand birds and their eggs," as ridiculous and absurd.
On the 24th of May I observed this species mastered and driven from its feeding grounds by the King-birds, Muscicapa Tyrannus, and the Martins, Hirundo purpurea. I am inclined to believe that these birds migrate in the same manner as many of our terrestrial species, that is, the females first, by themselves, and afterwards the males.
The Marsh Tern deposits its three eggs on the dried rushes found in the salt marshes at a short distance from the water, and carefully placed beyond reach of any ordinary encroachment of the tides; for, as WILSON has truly said, this species forms no nest. The eggs differ considerably in their markings. They are generally an inch and three-quarters in length, an inch and half an eighth in breadth, smooth, of a greenish or olivaceous tint, largely marked with irregular splashes of dark umber, almost black, disposed around the broadest part, leaving the apex with only a few small dots of the same colour, similar dots being as sparingly dispersed toward the smaller end, which falls off toward the extremity, and is there gently rounded. The parents sit more upon them than is usual with Terns which drop their eggs on the sands, and they do not leave their charge in cloudy weather. The young have the bill of a dull reddish orange-brown colour, the legs and feet of a less deep tint of the latter colour, which is retained by them until late in the winter, when these parts become black, and so continue for life.
The Marsh Tern does not extend its migrations eastward along our shores beyond New England; which will be understood by those who know, that in a continued direction the rocky shores afford them no place in which they could obtain food. But, from what I know of the extraordinary power of flight of this bird, I am not at all surprised at its being found in Europe, any more than I should be to find it cosmopolitan.
I here present the different measurements carefully taken from fresh birds of only four pairs, all shot in spring, and in full plumage, although of different ages. WILSON's measurements are as follows: "fourteen inches in length, and thirty-four in extent."
M. F. M. F. Length to end of tail, . 13 14 3/4 14 1/2 13 1/2 Length to end of claws, . 11 12 1/2 12 11 1/4 Length to end of wings, . 14 1/4 15 15 1/2 14 1/2 Extent of wings, . . . . 33 34 1/2 34 1/2 33 1/2 Tarsus, . . . . . . . 1 1/8 1 1/4 1 1 3/6 M. F. M. F. Length to end of tail, . 13 1/2 13 1/2 14 1/2 14 Length to end of claws, . 12 1/2 12 3/4 12 11 Length to end of wings, . 14 1/2 13 1/4 15 3/4 14 3/4 Extent of wings, . . . . 34 34 35 3/4 35 Tarsus, . . . . . . . 1 1/4 1 1 3/6 1 3/6
The weight of the four male birds was 6 1/2 oz., 5 7/8, 6 3/4, 7 1/8. The females were quite as heavy.
MARSH TERN, Sterna aranea, Wils. Amer. Orn., vol. viii. p. 143.
STERNA ARANEA, Bonap. Syn., p. 354.
MARSH TERN, Sterna anglica, Nutt. Man., vol. ii. p. 269.
MARSH or GULL-BILLED TERN, Sterna anglica, Aud. Orn. Biog., vol. v. p. 127.
Male, 14, 34.
Cosmopolite. In America, breeds from the mouth of the Mississippi to Connecticut. Not abundant. Migratory.
Adult Male in summer.
Bill about the length of the head, rather stout, compressed, acute. Upper mandible with the dorsal line nearly straight to the anterior edge of the nostrils, then arcuato-declinate, the ridge rather broad and rounded at the base, narrowed toward the end; the sides sloping at the base, nearly erect and convex toward the end, the edges sharp and inflected, the tip although narrow somewhat obtuse. Nasal groove comparatively short; nostrils basal, oblong, direct, pervious. Lower mandible with the angle very narrow and acute, extending to beyond the middle, the outline of the crura a little concave, that of the rest ascending and straight, a prominence or angle being formed at their junction as in Gulls, the sides erect and slightly convex, the edges sharp and inclinate, the tip acute, the gap line straight for half its length, then slightly arcuato-declinate.
Head of moderate size, ovate; neck of moderate length; body slender. Feet small; tibia bare for nearly half an inch; tarsus very short, compressed, anteriorly scutellate; toes small, slender; the first extremely small, the third longest, the fourth considerably shorter; all scutellate above, the anterior connected by reticulated webs, of which the inner is more deeply emarginate. Claws a little arched, compressed, very slender, that of the middle toe much larger, and having its inner edge somewhat dilated.
Plumage soft, close, blended, very short on the fore part of the head. Wings very long, narrow, and pointed; primary quills tapering to an obtuse point; the first longest, the second ten and a half twelfths of an inch shorter, the rest rapidly graduated; secondaries short, incurved, obliquely rounded, some of the inner proportionally longer and narrower. Tail of moderate length, forked, of twelve feathers, of which the middle are rounded and an inch and seven-twelfths shorter than the outer, which tapers to a narrow but obtuse point.
Bill black, as are the feet. Iris brown. The upper part of the head, the nape, and part of the hind neck, deep black; sides of the head, including a line margining the base of the upper mandible, fore neck, and all the lower parts white; upper parts pale greyish-blue; the edges of the wings whitish; the primary quills hoary on the outer web, deep grey on the inner, but with a large portion toward the base lighter, the shafts and those of the tail-feathers white; the tail is of a paler tint than the back, and the outer feather is nearly white.
Length to end of tail 14 inches; extent of wings 34; bill along the ridge 1 6/12, along the edge of lower mandible 2 1/12; wing from flexure 12 1/12; tail to end of middle feather 3 4/12, to end of lateral feather 4 11/12; tarsus 1 1/4; first toe (3 1/4)/12, its claw (2 1/2)/12; middle toe 10/12, its claw (4 3/4)/12.
A female from the mouths of the Mississippi, April 1, 1837. On the roof of the mouth are three longitudinal ridges; the posterior aperture of the nares is linear, with an anterior slit; the tongue slender, tapering, 1 inch 2 twelfths long, papillate at the base, the outer papilla on each side larger, the tip sharp and horny. The oesophagus, Fig. 1 [a b c], is 5 inches long, very wide, its greatest diameter 9 twelfths. The stomach, [c d e], is oblong, 1 inch 2 twelfths in length, 10 twelfths in breadth; its lateral muscles moderate. Its contents are coleopterous and hymenopterous insects, together with small crabs. The epithelium is thick, strong, prominently rugous, of a reddish-brown colour, and exactly resembling that of the smaller Gulls. The proventricular glandules are very small, and form a belt 1/2 inch in breadth. The intestine, [f g h i], which is 1 foot 8 inches long, is wide, its average diameter being 4 1/2 twelfths. The coeca, which come off at the distance of 2 inches from the anus, are very small, being 3 twelfths long, and 1 twelfth in diameter.
The trachea is 4 inches 2 twelfths long, at the upper part 4 twelfths in breadth, gradually contracting to 1 1/2 twelfths. The rings, about 110, are feeble and unossified. The bronchial rings are about 20. The contractor muscle is so thin as to be scarcely perceptible; the sterno-tracheal extremely slender. There is a single pair of inferior laryngeal muscles.
The stomach of another female contains the remains of crustaceous animals, one of which, nearly entire, is a small roundish crab, 11 twelfths in breadth.
For more on this species, see its entry in the Birds of North America Field Guide.