The young birds are similar to the female, but paler, and without the green speculum.
In a male, the roof of the mouth is deeply concave, with a prominent middle ridge, on which are a few blunt papillæ; on the upper mandible are 50 lamellæ, on the lower about 65 below, and 85 above. The tongue, 8 twelfths long, large and fleshy, has two rows of lateral bristles. The œsophagus is 8 1/2 inches long, 4 twelfths in diameter until the middle of the neck, when it enlarges gradually to half an inch. The proventriculus is 1 1/4 inch in length, with oblong glandules. The stomach is a strong roundish gizzard, 1 inch and 2 twelfths long, 1 1/2 inch broad; its left muscle 7 twelfths thick, the right 6 1/2 twelfths; its cuticular lining or epithelium of moderate thickness and longitudinally rugous. The intestine, 5 feet 1 inch long, varies in diameter from 3 to 2 twelfths; the cœca are 2 inches 10 twelfths long, cylindrical and rounded, their diameter 3 twelfths; the cloaca globular. The contents of the stomach were gravel and seeds of plants.
The trachea is 6 inches and 2 twelfths long; its diameter at the top 4 twelfths, at the middle 2 twelfths, at the lower part 3 1/2 twelfths. The inferior larynx is formed of three or four united rings, and has an irregular roundish bony expansion on the left side. The number of rings of the trachea is 98, of the bronchi about 25. The contractor muscles are large; cleido-tracheales and sterno-tracheales. to reproduce out of season, as it were. On some such occasions, when I was at St Augustine, in the month of December, I have observed four or five males of the present species paying their addresses to one female, who received their courtesies with evident welcome. Yet the females in that country did not deposit eggs until the 20th day of April. The most surprising fact of all was, that, although these birds were paired, and copulated regularly, by the 1st of February, not one had acquired the spring or summer plumage, or the dark coloured hood, or the rosy tint of the breast, nor lost the white spots on the tips of their primary quills. This change, however, was apparent by the 5th of March, became daily stronger, and was perfected by the 15th of that month. A few exceptions occurred among the numbers procured at these periods, but the generality of the birds were as above described.
Whilst at Great Egg Harbour, in May 1829, shortly after my return from England, I found this species breeding in great numbers on the margins of a vast salt marsh, bordering the sea-shore, though separated from the Atlantic by a long and narrow island. About sunrise every morning, an immense number of these birds would rise in the air, as if by common consent, and wing their way across the land, probably intent on reaching the lower shores of the Delaware River, or indeed farther towards the head waters of Chesapeake Bay. They formed themselves into long straggling lines, following each other singly, at the distance of a few yards. About an hour before sunset, the same birds were seen returning in an extended front, now all silent, although in the morning their cries were incessant, and lasted until they were out of sight. On arriving at the breeding ground, they immediately settled upon their nests. On a few occasions, when it rained and blew hard, the numbers that left the nests were comparatively few, and those, as I thought, mostly males. Instead of travelling high, as they were wont to do in fair and calm weather, they skimmed closely over the land, contending with the wind with surprising pertinacity, and successfully too. At such times they were also quite silent. I now and then observed some of them whilst on wing, and at a considerable height, suddenly check their course, as if to examine some object below; but on none of these occasions did I see one attempt to alight, for it soon resumed its wonted course, and rejoined its companions.
Now, Reader, though I am growing old, I yet feel desirous of acquiring knowledge regarding the habits of our birds, and should much like to learn from you the reasons why these gulls went off in lines from their breeding grounds, and returned in an extended front? Was it, in the latter case, because they were afraid of passing their nests unknowingly; or, in the former, under the necessity of following an experienced leader, who, under the stimulus of an empty maw, readily undertook the office, but who, like many other bon-vivants, became in the evening too dull to be of use to his companions?
This species breeds, according to the latitude, from the 1st of March to the middle of June; and I have thought that on the Tortuga Keys, it produced two broods each season. In New Jersey, and farther to the eastward, the nest resembles that of the Ring-billed Gull, or Common American Gull, Larus zonorhynchus, being formed of dried sea-weeds, and land plants, two and sometimes three inches high, with a regular rounded cavity, from four and a half to five inches in diameter, and an inch and a half in depth. This cavity is formed of finer grasses, placed in a pretty regular circular form. I once found a nest formed as it were of two; that is to say, two pairs had formed a nest of nearly double the ordinary size, and the two birds sat close to each other during rainy weather, but separately, each on its own three eggs. I observed that the males, as well as the females, thus concerned in this new sort of partnership, evinced as much mutual fondness as if they were brothers. On the Tortugas, where these Gulls also breed in abundance, I found their eggs deposited in slight hollows scooped in the sand. Whilst at Galveston, in Texas, I found their nests somewhat less bulky than in the Jerseys, which proved to me how much birds are guided in these matters by differences in atmospheric temperature and locality.
I never found more than three eggs in a nest. Their average length is two inches and half an eighth, their greatest breadth a trifle more than an inch and a half. They vary somewhat in their general tint, but are usually of a light earthy olive, blotched and spotted with dull reddish-brown and some black, the markings rather more abundant towards the larger end. As an article of food, they are excellent. These gulls are extremely anxious about their eggs, as well as their young, which are apt to wander away from the nest while yet quite small. They are able to fly at the end of six weeks, and soon after this are abandoned by their parents, when the old and young birds keep apart in flocks until the following spring, when, I think, the latter nearly attain the plumage of their parents, though they are still smaller, and have the terminal band on the tail.
The Black-headed Gull frequently associates with the Razor-billed Shearwater, Rhynchops nigra, in winter; and I can safely say that I have seen more than a thousand of each kind alight on the same points of estuaries and mouths of rivers; the Gulls standing or sitting by themselves, at no great distance from the Razor-bills. Now and then they would all suddenly rise on wing as if frightened, perform a few evolutions in the air, and again settle on the very same spot, still, however, keeping separate. While thus in the company of the Razor-bills, the Gulls are with great difficulty approached, the former being exceedingly wary, and almost always rising when a person draws near, the Gulls immediately following them, and the two great flocks making off to some distant point, generally not very accessible. If taken up on being wounded, these gulls are apt to bite severely. If, on being shot at, they fall on the water, they swim fast and lightly, their companions all the while soaring above, and plunging towards them, as if intent on rescuing them. This great sympathy often proves fatal to them, for, if the gunner is inclined, he may shoot them down without any difficulty, and the more he kills the more his chances are increased.
On the 10th of May 1832, it was my good fortune to be snugly on board the “Lady of the Green Mantle,” or, in other words, the fine revenue cutter the Marion. The Gulls that laughed whilst our anchors were swiftly descending towards the marvellous productions of the deep, soon had occasion to be sorrowful enough. As they were in great numbers, officers and men, as well as the American Woodsman, gazing upon them from the high decks of the gallant bark, had ample opportunities of observing their motions. They were all busily engaged on wing, hovering here and there around the Brown Pelicans, intent on watching their plunges into the water, and all clamorously teasing their best benefactors. As with broadly extended pouch and lower mandible, the Pelican went down headlong, so gracefully followed the gay rosy-breasted Gull, which, on the brown bird’s emerging, alighted nimbly on its very head, and with a gentle stoop instantly snatched from the mouth of its purveyor the glittering fry that moment entrapped!
Is this not quite strange, Reader? Aye, truly it is. The sight of these manœuvres rendered me almost frantic with delight. At times, several gulls would attempt to alight on the head of the same Pelican, but finding this impossible, they would at once sustain themselves around it, and snatch every morsel that escaped from the pouch of the great bird. So very dexterous were some of the Gulls at this sport, that I have seen them actually catch a little fish as it leaped from the yet partially open bill of the Pelican. And now, Reader, I will conclude this long article with some fragments from my journals.