Sandwich Tern

The Sandwich Tern is pale gray above and white below with a forked tail and a thin, yellow-tipped black bill. Black cap.

Photograph © Greg Lavaty

Sexes similar.

The head becomes partly white in winter.

Juveniles resemble winter adults.

Coastal areas and beaches.

Fish.

Forages by plunging into the water head-first from the air.

Photograph © Greg Lavaty

Breeds along the Atlantic and Gulf Coasts.

Sandwich Terns often nest with Royal Terns and Laughing Gulls.

Male Sandwich Terns feed females during courtship.

“Gwit” or “kek” calls are given.

The nest is a scrape on the ground.

Number: 1-2.
Color: White with darker markings.

Incubation and fledging:.
– Young hatch at 21-29 days.
– Young fledge (leave the nest) shortly after hatching but remain with young from 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 Sandwich Tern – the common name and sub-species reflect the nomenclature in use at the time the description was written.

Among the sandy islands and shoals of our southern Atlantic and Gulf coasts we find this fine tern, everywhere intimately associated with its larger relative, the royal tern; like Damon and Pythias, they are always together and seldom is one found without the other. The same resorts seem to be congenial to both, but there is probably some stronger bond of friendship which we do not understand. Our American bird is only subspecifically distinct from the Sandwich or Boy’s tern of the Eastern Hemisphere, differing from it in the color pattern of the primaries. This makes the species cosmopolitan and gives it a wide range. The European bird ranges farther north in summer than ours, which may be due to the difference in climate.

What little evidence we have on the subject seems to indicate that this species has extended, and is perhaps still extending, its breeding range northward along our Atlantic coast. This, if it is a fact, is both interesting and remarkable when compared with the histories of other species, nearly all of which have been reduced in numbers and restricted in range. In Audubon’s time, Cabot’s tern was not supposed to breed north of Florida. Royal Shoal Island, in Pamlico Sound, North Carolina, had been protected and watched carefully, as a sea-bird breeding resort, for five years before Mr. T. Gilbert Pearson (1908) discovered the first breeding colony, over 20 pairs, of Cabot’s terns on this island on June 25, 1907. Mr. Pearson says, in reporting the incident:

This bird has not previously been noticed breeding among the protected cobflies in the State, and in fact, so far as I am aware, there have been no records of its occurrence in North Carolina, except one reported by Dr. Louis B. Bishop (MS.), from Pea Island, August 22, 1904.

Since that time I believe that Cabot’s tern has bred regularly on the North Carolina coast and in larger numbers. And now comes the latest news from Mr. Harold H. Bailey (1913), telling of the extension of its breeding range into Virginia. He says:

This is an extremely rare bird on our coast, and it was not until the summer of 1912 that a set of two eggs of this species ~vas secured from one of our coastal islands. As there has been a small colony of these birds breeding on the North Carolina coast for the last few years, the birds with us are probably stragglers from that colony.

Spring: North of Florida this species is only a summer resident, the northward migration starting in Florida about the 1st of May. It is rather a late breeder. Even on the Gulf coast egg laying does not begin until the last of May, and farther north it is two or three weeks later.

Nesting: The only breeding colony of this species that I have ever seen was on Grand Cochere Island, in the Breton Island reservation. This was a low, flat sandy island, hardly more than a sand bar, 114 miles offshore, south of Pass Christian, Mississippi. I have given a fuller description of it under the royal tern. When I visited this island on June 18 and 19, 1910, I estimated that its bird population consisted of about 7,000 royal terns, 2,000 Cabot’s terns, 600 black skimmers, 80 Caspian terns, and 20 laughing gulls. These estimates were arrived at by counting the nests in a measured area and then roughly measuring the total area occupied by the colonies.

There were several small mixed colonies of royal and Cabot’s terns, but the bulk of the population was concentrated in one vast colony of approximately 3,500 nests. In this and in the smaller colonies the Cabot’s terns were grouped together in certain sections by themselves, though not in any way separated from the general continuity of the colony; but their nests were seldom, if ever, scattered singly among the royal terns. The nests of both species were evenly spread out over a level, sandy plain, above the ordinary hightide mark, in the central portion of the island, which was entirely devoid of vegetation – a hot, dry waste of sand. They were apparently placed at measured distances, just far enough apart for each sitting bird to be beyond the reach of its neighbor; probably the distances were actually measured by the birds when the eggs were laid, each bird choosing a spot as close to its neighbor as seemed safe from the jabs of a long, sharp bill. The nests were hardly worthy of the name, for they were never more than slight hollows in the sand, with no attempt at lining whatever, and often the eggs seemed to have been dropped on the smooth, flat sand without even a pretense at a hollow. Nearly all of the nests held one egg each, but a few held two. This colony had been washed off another island earlier in the season and had come here for a second attempt at nesting. Captain Sprinkle told me that both of these terns usually lay two eggs at the first laying and only one at the second. The Cabot’s terns in this colony were very tame, even tamer than the royal terns. After they became accustomed to my presence I had no difficulty in photographing them at short range without the use of a blind. I was disappointed to find no young in the colony, which would have given me an opportunity to study their home life even better.

From what I can learn from the writings of others this colony was fairly typical of the species and descriptions of other breeding colonies, all of which seem to be on low sandy islands on the seacoast, would be useless repetitions. On the other side of the Atlantic, however, the nesting habits of the species may differ, as several writers speak of nests among the beach grass and nests lined with dry grass. References to such nesting habits by American writers are probably based on the statements of foreign writers.

Mr. W. E. D. Scott (1888) took some young birds on September 20, 1886, “not quite fully grown, indicating that probably more than one brood is raised, and showing how late in the summer the last broods are hatched out.” If this species raises two broods it is a notable exception to the rule among the terns; probably Mr. Scott’s birds were hatched out late in the season, because earlier attempts were frustrated by storms or other destructive agencies. Cabot’s tern has been said to lay as many as three or four eggs to a set, but I believe that such large numbers are excedingly rare, on this side of the Atlantic at least. Two eggs seem to be the normal number, with occasionally three. One egg to a nest is the rule on second and subsequent layings.

Mr. Stanley C. Arthur writes me regarding his observations on this species:

There was very little opportunity given me at this time to study the Cabot tern and its young, as what little ones were there were absolutely in the downy stage and evidently too young to eat, for at no time did I see a young Cabot being fed by its parent. I did, however, see the male (7) bringing the female (7) fish food while she was engaged in incubating a single speckled egg which she covered. Here I had an excellent opportunity to learn that the Cabot tern incubated but one egg. While it Is true that In one or two instances there were two eggs, so close to make it appear they belonged to a single clutch, yet when the mother bird settled on them she threw her breast feathers over one egg, to the other paying not the slightest concern. In fact, at one time I saw a Cabot tern cover a single egg and with her bill roll the other some inches away from the hollow In which she had deposited her own.

At this time I made an experiment, contemplated for the past several years. I had often wondered why it is, where there are several thousand single speckled eggs, such as the Cabot terns deposit on the beaches, one particular egg can be singled out by the parent as her own private and individual property, and have often wondered whether or not they can, with certainty, know their own egg. I have often been asked: “How does the tern know its own eggs 7” and have always facetiously answered: “By counting the spots.” As I was studying the birds I selected two Cabots, one on the left and the other on my right, that were marked quite distinctly – one having a wholly black crest and one having its crest speckled with a few white feathers which heralded the coming of the winter plumage.

At 11.15 I left the blind, which naturally scared off the birds, and changed the egg on my left, which had been covered by the pure black-headed tern, and moved it several feet away, exchanging it for the egg that had been covered by the Cabot with white feathers In its crest. This egg was placed on the spot belonging to the black-headed tern. At 11.18 the circling and frantically crying birds commenced resettling on their eggs, and showing not the slightest concern each tern sought its own egg despite the fact that it had been moved several feet and placed in a different nest. After allowing each bird to remain on its egg for 15 minutes, I again left the blind and retransferred the eggs with the same result as before. Each parent bird settled on its own egg without hesitation, and, as before, not evidencing any surprise over the change of the location.

The eggs of Cabot’s tern are certainly beautiful and subject to great variation; they make one of the prettiest series in the egg collector’s cabinet. The ground color on the prettiest eggs varies from “seashell pink” to “pale cinnamon pink,” or from “pale pinkish buff” to “pale ochraceous buff.” Some show various olive shades, from “olive buff” to “light buff;” others vary from creamy white to pure dull white. The markings vary endlessly in size, shape, and extent. Some eggs are uniformly covered with small spots, densely or sparingly; others are boldly marked with large heavy blotches or irregular, fantastic scrawls. These markings may be confluent in a ring at either end. The markings are usually in the darkest shades of “blackish brown” or black; occasionally they are more or less washed out on the edges, as in the royal tern’s eggs; occasionally blotches or scrawls of ” burnt umber” or ” russet” are overlaid with darker shades; spots, blotches, and scrawls of “pale lavender gray” are seen under the bolder markings. Often both fine spots and bold scrawls are seen on the same egg. When these include two shades of brown and the lavender gray on a pink background the effect is beautiful. One odd egg in my collection has the pink ground color nearly concealed by fine scrawls of several shades of reddish brown, suggesting certain types of falcon’s eggs. The shell is smooth, but without luster. The shape varies from ovate to elongate ovate. The measurements of 41 eggs, in the United States National Museum and the writer’s collections, average 51.1 by 36 millimeters; the eggs showing the four extremes measure 57 by 37.5, 51.5 by 38.5 and 46 by 33 millimeters.

Young: Incubation seems to be shared by both sexes and lasts for about three weeks. Morris (1903) quotes Selby as saying: As soon as the young birds become tolerably fledged, but before they are altogether able to fly, they frequently take to the water, swimming off to the smaller rocks, where they continue to be fed by the parents until capable of joining them In their fishing excursions.

Plumages: Downy young Cabot’s terns do not show so much variation as young royal terns and will average much lighter in color. They are seldom much darker than “cartridge buff” on the upper parts and are usually buffy white or white. They are also usually immaculate; often a few small dusky tips are seen on the down of the back, and occasionally an individual is uniformly mot tied with such dusky tips over the entire back and pileum. The bill is light yellowish flesh-color, and the feet either the same or dull grayish in the dried skin. The juvenal plumage appears first on the scapulars, back, and wings. In the juvenal plumage the forehead and crown are white, the latter streaked with black, which increases on the occiput and auriculars to nearly solid black; the back and scapulars are boldly marked with black spots and V-shaped markings, which are largest and most prominent on the scapulars; the remiges are slaty gray with white edges; the rectrices are grayish white with dusky subterminal areas or black-spotted near the tips; there is a grayish cubital band on the lesser wing-coverts and the greater coverts are washed with pale gray; the under parts are white. A partial postjuvenal molt begins in September, at which the dark markings disappear and the first winter plumage is assumed. This is similar to the adult winter plumage except that the wings and tail of the juvenal plumage are retained. This plumage is worn all winter until the first complete prenuptial molt in the early spring, at which probably most young birds assume a plumage practically indistinguishable from the adult.

Adults have two complete molts each year. The prenuptial molt occurs between March and May, producing the well-known breeding plumage. The postnuptial begins early in July and often lasts through August and September. In winter adults the yellow tip of the bill is duller and more restricted; the forehead is white, the crown narrowly streaked with black, and the occipital crest is brownish black; the tail is shorter than in the spring and shows some gray near the end.

Food: The food of Cabot’s tern consists almost wholly of small fish, such as small mullets, sand launces, and young garfish, which it obtains by making vigorous plunges into the water much after the manner of other terns; but it also eats shrimps and squids. It is more of a sea bird than the smaller terns, and is more often seen feeding out on the open sea or among the breakers than in the quiet tidal estuaries. Audubon (1840) thus describes its feeding habits:

While plunging after the small mullets and other diminutive fishes that form the principal part of its food, It darts perpendicularly downward with all the agility and force of the common and arctic terns, nearly Immersing its whole body at times, but rising Instantly after, and quickly regaining a position from which it can advantageously descend anew. Should the fish disappear as the bird is descending the latter instantly recovers itself without plunging into the water.

Behavior: In flight this is one of the swiftest and most skillful of the terns. Its long, slender, pointed form is highly specialized for speed and ease in cutting the air. Mr. Montague Chamberlain (1891) says:

Its strength of wing and skill enable It to outride the severest storms, and flocks of these birds may be seen dipping into crested waves or skimming over angry breakers to seize the prey that may be brought to the surface by the gale.

Intermediate in size between the two large terns and the several smaller species, it seems to combine the strength and vigor of the former with the activity of the latter. It may be distinguished from either by its shape and by its long, slender bill. The yellow tip of its bill is quite conspicuous at short range.

Its cry is short, sharp, loud, and shrill. Audubon (1840) refers to it as “sharp, grating, and loud enough to be heard at the distance of half a mile.” Morris (1903) calls it “a loud, hoarse, and grating cry or scream, likened to the syllables ‘pink’ or ‘cree.'” Yarrell (1871) noted the syllables “kirhitt, kirhitt.” When disturbed on its breeding grounds, or when feeding in flocks, it is very noisy.

Winter: Throughout the southern portions of its breeding range in this country, on the southern Florida and Gulf coasts, Cabot’s tern is a permanent resident, its numbers being increased by the addition of migrants from more northern points. The species withdraws in the fall from its summer resorts, on the coast of Virginia, the Carolinas, and northern Florida, to its winter home in the Bahamas, the Gulf of Mexico, and the coasts of Central and South America. Here it spends the winter roaming about the outer islands and sand bars in company with other terns and gulls, following schools of fish or resting in flocks on the sand. At this season it is highly gregarious and quite shy.

DISTRIBUTION
Breeding range: Atlantic and Gulf coasts from Virginia (Northampton County) to British Honduras (Saddle Cay). Some of the Bahamas (Acklin and Ragged Islands, Samana Keys, etc.), and West Indies (from Cuba to Dominica).

Winter range: From the Bahamas and Florida southward through the West Indies and along the Atlantic coast of South America to southern Brazil (Iguape). From the coasts of Louisiana and Texas southward, along the Central American coast to Colombia (Cartagena). And on the Pacific coasts of Oaxaca (San Mateo) and Guatemala (Chiapam).

Spring migration: Birds depart from coast of Brazil during March and April and first arrivals reach South Carolina, Capers Island, April 9.

Fall migration: Apparently in September, but data is very scanty.

Casual records: Stragglers have wandered in summer as far north as Massachusetts (Chatham, August, 1865). Three specimens taken in spring of 1882 in Lucknow, Ontario. A few remain in Brazil in summer (Iguape, June, and Rio Janeiro, August).

Egg dates: Texas: Eighteen records, April 25 to June 14; nine records, May 17 to 28. Bahamas: Twelve records, May 14 to June 20; six records, May 16 to 22.