Royal Tern

The Royal Tern has an orange bill, pale gray upperparts, white underparts, and black legs. Black cap.

Photograph © Greg Lavaty

Sexes similar.

Winter birds lose the black cap and instead have black only at the back of the crown.

Juveniles resemble winter adults.

Coastal bays and beaches.

Fish and crustaceans.

Forages by plunging into the water from flight.

Royal Terns are resident along the coast of the southeastern U.S. and Mexico, and breed somewhat farther north along the Atlantic Coast. Also occurs in South America and Africa.

John James Audubon confused Royal Terns with Caspian Terns.

Although a good swimmer, the Royal Tern never sleeps on the water.

A loud “keet” call and “kleer-kleer” calls are given.

The nest is a depression on the ground.

Number: 1.
Color: White with darker markings.

Incubation and fledging:
– Young hatch at 30-31 days.
– Young fledge (leave the nest) in 2-3 days after hatching but remain with the adults and young of other pairs for some time.

Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.

Bent Life History for the Royal Tern – the common name and sub-species reflect the nomenclature in use at the time the description was written.

Although the royal tern is a splendid bird it seems to me that the name “royal,” as well as the specific name maxima, should have been applied to its near relative, the Caspian tern, which is both larger and more aggressive, a real king among the terns. The two species so closely resemble each other that so good a naturalist as Audubon did not recognize them as distinct, confusing the two under the name, Cayenne tern.

Throughout the southern portion of its range, from Florida and the Gulf of Mexico southward, the royal tern is resident throughout the year. Northward to Virginia it occurs as a summer resident only, and beyond that merely as a straggler. In former years royal terns bred abundantly on the coast of Virginia. Mr. Robert Ridgway (1880) in the summer of 1880 found and reported a breeding colony of some 500 nests, but in the persecution which followed during the next 20 years this species suffered with the other terns which were slaughtered for the millinery trade. On account of their large size royal terns were not in demand for ladies’ hats, but their eggs, being large and palatable, were collected for food in great quantities. Persistent nest robbing and constant shooting near their breeding grounds discouraged the birds and frightened them away. The reports of the wardens in 1901 and 1902 indicated that the colonies were much depleted until, in 1903, Capt. N. B. Rich stated, in Mr. Dutcher’s (1903) report, that he “did not see any royal terns, so they probably have been exterminated so far as Virginia 15 concerned.” During my visit to Cobb’s Island in 1907 I did not see any royal terns, but was told by the fisherman that a few are seen occasionally. Since that time conditions have evidently improved under protection, for Mr. Harold H. Bailey (1913) says:

The royal terns are much more numerous, a large colony still breeding on one of our coastal Islands. They did, however, for a number of years during the overwhelming destruction of some of the following species for millinery trade, desert our coast entirely, but it has only been within the last few years that they have become established as breeding birds once more.

Spring: On its spring migration the royal tern, according to Bailey (1913), reaches Virginia “the last week in May,” although, according to Coues (1877), it arrives in North Carolina “early in April.” Its migration is so limited that its movements are probably very deliberate and perhaps quite erratic or variable. I have never seen its courtship performance and can find nothing about it in print.

Nesting: An old-time colony on the Virginia coast is described by Ridgway (1880) as follows:

Allowing the birds sufficient time to deposit their eggs, we visited the locality two days afterwards, and found an area of perhaps one-eighth of an acre completely coveied by their eggs, It being impossible to walk through the nesting site without crushing a greater or less number, many eggs having been covered by drifting sand. Comparatively few pairs had deposited their full complement, a large majority of the nests containing but a single egg. still, more than 500 nests were counted, while our man declared that not one-third the number of birds seen by him on his former visit were there, the greater part having been frightened away by the shots which he had fired at them two days before.

In Virginia, the bird is known as the “gannet striker” or gannet.”:

Mr. B. S. Bowdish (1910) and Mr. P. B. Philipp discovered four breeding colonies of royal terns on the coasts of the Carolinas in 1909, as follows:

The first was situated on Vessel Reef, a low sand key in Bulls Bay, South Carolina, visited on June 12. About 75 birds were seen there and nesting had just begun, three fresh eggs being found. The second colony was on Royal Shoal, Pamlico Sound, North Carolina. Here, instead of the enormous numbers of the preceding season, estimated at some 7,000 birds, only 50 were found. On June 24 one fresh egg was noted. The third and largest Colony was found on June 26, on Miller Lump, a small, low sand bar In Parulico Sound, lying in a broad expanse of very shallow water. This colony comprised 1,000 adult birds. The nesting was advanced; some 258 good eggs were counted, usually one egg to a set, though a few doubles were found. There were also many young, some of which were able to run about. All the eggs were advanced in incubation. The fourth breeding colony visited was on Davis Lump, a small sand bar near Miller Lump. Here about 60 pairs of birds were breeding. Thirty-two eggs were counted, for the most part advanced in incubation. Half a dozen newly hatched young were also seen.

My own experience with the nesting habits of the royal tern was gamed in the large protected colonies of the Breton Island reservation, off the coast of Louisiana, where the birds have certainly flourished during the recent years. They are now safe from the depredations of man, but they still suffer occasionally from the destruction of their breeding colonies by the elements. The combination of high winds or storms with a high course of tides often results in the flooding of the low sandy islands on which they breed and the washing away of the eggs or young; but such wholesale damage is generally repaired by a second attempt at nesting.

On June 18, 1910, with Warden XV. M. Sprinkle, in his patrol boat, I visited one of these colonies. Sailing due south from what seemed to be the outer islands, we headed straight out to sea and were soon out of sight of land. After several hours of apparently aimless sailing Captain Sprinkle pointed out on the horizon a distant sand bar, and as we drew nearer we could see with our glasses a cloud of white specks hovering over it, so we knew that the terns were nesting there as expected. They had been washed off one of the other islands earlier in the season and had come here to make their second attempt at nesting. The island, which is known as Grand Cochere, was merely a low, flat sand bar, with no vegetation on it whatever, only 2 or 3 feet above high-water mark at its highest part. It was nearly triangular in shape, perhaps half a mile long, and surrounded by dangerous sandy shoals. On an old wreck at one end 30 or 40 man-o’-war birds were perched in a long black row; a large flock of brown pelicans were resting on one of the sand bars; and- at night thousands of black terns came in to roost on the beaches. There were several small nesting colonies of black skimmers, and three or four small mixed groups of royal and Cabot’s terns, scattered over the island with their eggs lying in the dry, hot sand, as well as a few scattering pairs of laughing gulls and a little colony of 40 nests of Caspian terns at the eastern end. But the main population of the island was concentrated in an immense, closely packed nesting colony of royal and Cabot’s terns on the south side. As I approached this colony, over the level sandy plain on which it was spread out, the birds all arose at once, as if impelled by a common impulse, with a great roar of thousands of wings, a dense cloud of screaming birds, and a bewildering moving picture of flashing black and white. As the birds were shy my attempts at photography resulted in only a few distant snapshots of the colony as a whole; so I set up my blind in the midst of the colony and left it overnight for the birds to get accustomed to it. On my return the next morning I was delighted to find that the terns had learned to regard my blind as harmless and had settled down on their nests all around it. Walking up to the blind, with two companions, I concealed myself inside of it with my cameras, and the other two men walked away. The birds, thinking that all of us had gone, immediately returned and assumed their regular vocations. For two or three hours I sat there unobserved and watched the activities of that populous colony. All around me the flat sandy plain was dotted with eggs, a single egg in each little hollow in the sand at regular distances, just far enough apart so that the birds could not touch each other when sitting. It was a hot, sunny day, probably too hot for the eggs to be left uncovered, so the birds spent most of their time incubating; but there were many birds standing beside their sitting mates. There was not sufficient difference between the sexes for me to determine whether both sexes incubate or not, but probably they relieve each other occasionally. There were no young in the colony, so I could not study their method of feeding them. Life is never dull in a large bird colony and the birds are never still; some were coming and some were going all the time; there was a constant babel of voices and numerous little squabbles occurred, if an incoming bird alighted too near its neighbor. They were so close together that they could hardly spread their wings without interfering. An air of nervous excitement seemed to pervade the colony all the time, as in a crowd of women at an afternoon tea, and at frequent intervals, without any apparent cause, a large portion of the colony would rise suddenly and simultaneously, as if frightened, fly around for a minute or two, all screaming excitedly, and then all would settle down again as if nothing had happened.

I counted the nests in a measured area and then roughly measured the whole colony, from which I estimated that it contained, at least, 3′,500 nests. There were a hundred nests in a space four yards square; certainly this was a densely packed colony of a highly gregarious species.

The colony described above may be considered as typical of the species, which almost always nests in similar situations in closely populated colonies. The nest is nothing more than a slight hollow in the sand, without any attempt at a lining. I believe that the normal set consists of two eggs; very rarely three are found and four eggs have been recorded, though these were probably laid by two birds. Often only one egg is laid, and where the first set has been destroyed, only a single egg is laid for the second set. Two eggs are more often found in northern colonies, but in the southern portion of its range this tern usually, or at least frequently, lays only one egg for the first set. Only one brood is raised in a season, so far as I know.

Eggs: The eggs of the royal tern are usually quite characteristic and are not likely to be mistaken for anything else. They are quite different from those of the Caspian tern. In shape they vary from ovate to elongate ovate or even cylindrical ovate, but average about elongate ovate. The shell is smooth but without luster until it becomes worn by incubation. The common types have a very light ground color, practically white, varying from “light buff” or “ivory yellow” to pure dull white. Darker shades are rare, but I have a few in my collection which vary from “clay color” or “cinnamon buff ” to “light buff.” The greener types,” olive buff ” or ” yellowish glaucous,” are still rarer. The eggs are usually quite evenly spotted with small, dark-colored spots, sometimes with fine dots and sometimes with large, bold, heavy blotches; very rarely they are marked with irregular scrawls. The markings include only the darkest shades of brown, “chestnut brown,” “bister,” or “clove brown,” and often they are practically black. The spots have a washed-out appearance on the edges. On many eggs there are underlying spots of “lavender gray ‘~ or “pale violet gray,” often in washed-out splashes. Sparingly spotted or even immaculate eggs are occasionally found. The measurements of 54 eggs, in the United States National Museum, average 63 by 44.5 millimeters; the eggs showing the four extremes measure 74.5 by 48.5, 57.5 by 43, and 63.5 by 40.5 millimeters.

Plumages: In a series of 10 downy young royal terns, in the author’s collection, no two are alike, and there are, at least, three distinct types of coloration. In the palest type the color of the upper parts varies from “light pinkish cinnamon” to “pale pinkish buff,” which becomes paler on the throat and sides and almost white on the belly. Some specimens are nearly immaculate, but there are always a few small black-tipped filaments of down on the rump and often a few on the head. The character of the down is peculiar; on the head is rather stiff and hair-like, but on the back and flanks each filament stands out by itself, round and soft like chenille at the base and tapering to a fine point at the end. The bill and feet are light yellowish flesh color in the dried skin.

In the mottled type the color varies from “light pinkish cinnamon” to “cartridge buff” above, shading off to the latter or to nearly white below. This is more or less heavily spotted with black, more or less evenly, over all the upper parts, including the sides of the head, throat, and flanks. The spots are very distinct and include either the tip or the whole of the filament. The bill is light colored, and the feet may be light colored, as in the preceding type, or grayish or nearly black.

In the dusky type the ground colors are as described above, but they are largely, and sometimes almost wholly, concealed on the head, throat, back, wings, rump, and flanks with black or dusky filaments. Often the forehead and lores are solid black. The bill in this type has a subterminal black tip on one or both mandibles. The feet show both light and dark phases without any correlation with the other colors; in fact, my darkest specimens have the lightest feet. A larger series would probably show a great variety of intermediates between these three types and perhaps other types.

The juvenal plumage is fully acquired before the young bird is fully grown. It is entirely unlike that of the Caspian tern; the upper parts are mainly white with a faint creamy tinge, the feathers centrally tinged with light gray and with many narrow, dusky shaft streaks; the primaries and secondaries are “slate gray” or lighter, edged with white and the tail feathers are chiefly dusky, with white tips and white toward base of inner web; the underparts are pure white; the feathers of the crown have narrow, blackish shaft-streaks, becoming broader on the nape and auriculars, forming a dusky collar. This plumage is worn until about the last of August, when the postjuvenal molt begins. The wings and tail are retained and will serve to distinguish the young bird, but otherwise the first winter plumage is the same as the adult, the contour feathers being molted during the fall. A complete prenuptial molt occurs in March, at which the adult nuptial plumage is apparently assumed, but perhaps young birds do not acquire such a completely black pileum as adults.

Adults have two complete molts, the prenuptial in March or earlier and the postnuptial mainly in August and September, but often prolonged into October or even November, the outer primaries being molted last. The prenuptial molt, which produces the clear black pileum, is usually but not always soon followed by a partial molt on the head, which produces the white forehead, more or less variable in extent. The full black pileum seems to be the courtship plumage, and the white forehead the prevailing nesting plumage. Only a very small percentage of incubating birds have the pileum wholly black. In the adult winter plumage the forehead is white, the crown mainly so, but streaked with black, and only the occipital crest is mainly black. The tail is shorter and more tinged with gray than in spring.

Food: The food of the royal tern consists almost wholly of small fish, up to 4 inches in length, which it catches by plunging down into the water, in much the same way as the smaller terns. Mr. Philip H. Gosse (1847) thus describes the process:

High above the water we discern a bird, the snowy whiteness of whose plumage contrasts with the blue sky. He flies rapidly round and round in a large circle, quickly flapping his wings without intermission. Suddenly he arrests his flight, flutters his wings in rapid vibration, as he looks downwards, but in a moment proceeds as before. It was doubtless a fish near the surface, but which disappeared before he could descend. Presently he again stops abort, flutters; then bringing the elbow of the wings to a right angle, descends perpendicularly, but with a singular turning of the body, so as to present now the back, now the belly, alternately, to the observer; not, however, by a rotation, but irregularly, and as if by Jerks. But his purpose is again frustrated; for on nearly reaching the surface he recovers himself with a graceful sweep and remounts on flagging wing. Again he circles, and again, and again stops; at length, down he swoops, disappears with a splash, and in a moment breaks, struggling, from the wave, and, as if to rise burdened with prey were difficult, flags heavily near the surface, and circling slowly round, gradually regains his former altitude.

Audubon (1840) says:

They alight on the banks of raccoon oysters, so abundant in the inlets, and are seen in company with the semipaimated snipe and the American oystercatcher, searching for food like these birds, and devouring crabs and such fishes as are confined in small shallow pools. These they catch with considerable agility, in a manner not employed by any of our other terns.

Mr. A. W. Anthony (1906) says that they feed on herring “swimming in compact flocks near the surface,” and “secure them by approaching the school from behind and flying near the surface of the water, making repeated, quick dips into the school” They also eat shrimps.

Behavior: The flight of the royal tern is much like that of the common tern, but somewhat less bouyant, as might be expected in a larger and heavier bird, On the wing it is lighter in appearance than the Caspian tern, as it is more slender, and it has a longer and more deeply forked tail, with less black in the outer end of the wing. Audubon (1840) says:

When traveling, these birds generally proceed in lines; and it requires the power of a strong gale to force them back, or even to impede their progress, for they beat to windward with remarkable vigor, rising, falling, and tacking to right and left, so as to seize every possible opportunity of making their way. In calm and pleasant weather they pass at a great height, with strong unremitted flappings.

Though webfooted and perfectly capable of swimming, these and other terms seldom alight on the water and are very poor swimmers. Their feet are rather small and weak, as they depend almost entirely on their long wings for locomotion.

The voice of the royal tern is not so loud and raucous as that of the Caspian and is pitched on a higher key. The note most often heard, when disturbed on its breeding grounds, is a loud penetrating squawking cry, audible for a long distance, like the syllables,” quak,” or “kowk.” Another note on a lower key sounds like the bleating cry of a sheep. It also has a very musical, rolling call, a soft liquid whistle, “tourrrreee,” suggestive of the melodious rolling whistle of the upland plover.

This highly gregarious species is a sociable and harmless neighbor on its breeding grounds, where it is intimately associated with Cabot’s terns, black skimmers, and laughing gulls, which it apparently never molests. Its nests are preyed upon to some extent by the laughing gulls, though I believe that the royal tern is more than a match for the gull, as a rule. The royal tern is frequently seen fishing in company with the brown pelican, which it is said to rob occasionally by seizing the fish from its capacious pouch. The robber often pays the penalty for his crime by giving up his ill-gotten booty to the man-of-war bird, that arch robber of the southern seas, ever ready to pounce upon any bird weaker than itself and make it drop its catch.

Fall: In September the short migration flight begins, which is hardly more than a withdrawal from the northern portions of its breeding range, though its winter wanderings carry it to the Bahamas and the West Indies. The southward movement is deliberate. It leaves the coast of Virginia about the middle of September and lingers on the coasts of the Carolinas until the end of November. In its winter quarters, from Florida and the Gulf States southward, it prefers to frequent the harbors, estuaries, mouths of rivers, and the vicinity of sand shoals, where it may be seen fishing in company with brown pelicans, man-o-war birds, laughing gulls, and other terns, or perched on convenient spar buoys, or resting and dozing on the warm bare sand bars. It also roams inland to some extent in winter, visiting fresh water lakes and ponds. It is common along the Pacific coast in winter from Monterey Bay southward, in the harbors and about the islands, as well as in some of the lakes near the coast.

DISTRIBUTION
Breeding range: South Atlantic and Gulf coasts, from Virginia (Northampton County) to southern Texas (Cameron County). Some of the Bahamas (Berry and Ragged Islands, etc.) ; and many of the West Indies (Isle of Pines, Porto Rico, Dominica, Grenada, Carriacou, etc.). Pacific coast of Lower California (Natividad Island) and Mexico (Isabella Island).

Breeding grounds protected in the following national reservations: In Louisiana, Breton Island, Shell Keys, and Tern Islands.

Winter range: From central Florida (Micco) and from the coast of Louisiana southward, including the Bahamas and West Indies, along the east coasts of Central and South America to Patagonia. On the Pacific coast, from central California (San Francisco Bay) southward to Peru. Also on the west coast of Africa, from Gibraltar to Angola.

Spring migration: First arrivals reach North Carolina early in April, and Virginia during the last week in May.

Fall migration: Last birds leave Virginia about the middle of September, but they linger in North Carolina until late in November.

Casual records: Stragglers in summer wander northward along the Atlantic coast, sometimes as far as Massachusetts (Nantucket Island, July 1,1874).

Egg dates: North and South Carolina: Thirty records, May 15 to June 28; fifteen records, June 20 to 26. Texas: Sixteen records, April 8 to June 18; eight records, May 13 to 20. Mississippi and Louisiana: Eight records, May 18 to June 19; four records, May 19 to 29.