The RAPACIOUS TERNS (Sylochelidon) are the largest of the Sea Swallows, and distinguishable[Pg 178] from other species by their proportionately strong, compressed body, as also by their large strong beak, which is longer than the head. The foot is small, and the web but little excised; their wing is long and sabre-like; the tail but slightly forked; and the general plumage close and thick.
THE CASPIAN TERN.
The CASPIAN TERN (Sylochelidon Caspia) is twenty inches long, and fifty across the spread of its wings; the wing measures sixteen, and tail six inches; the feathers upon the top of the head are black, those on the sides of neck, upper back, and under surface of body, pure white; the mantle is light greyish blue; the tips of the wing-quills are darker and those of the tail-feathers lighter than the general colour of the upper parts of the plumage. The eye is brown, the beak coral-red, and the foot black. In winter the top of the head is black and white; in young birds the feathers of the back are transversely spotted with brown. The Caspian Tern inhabits Central Asia and Southern Europe; it breeds, however, exceptionally in the Island of Sylt, as well as upon some parts of the Dutch and French coasts. During the winter it appears upon the southern shores of the Mediterranean and the lower lakes of Egypt, as also in the northern parts of the Red Sea and Indian Ocean; it occurs on the west coast of Africa, but does not seem to have crossed the Atlantic. In England several specimens have been shot in Norfolk and other parts of the east coast. On the Island of Sylt it arrives towards the latter part of April, and after rearing its young, departs in August. This bird may generally be seen flying at a height of forty or fifty feet, its head, with its shining red beak, being directed downwards, and its great wings slowly waving, until from time to time it plunges headlong into the water after its prey. When in search of a resting-place it betakes itself with its companions to some rocky locality near the shore, where they all perch in a close rank, with their heads turned towards the sea, in which position they are readily mistaken for Sea Gulls. The term rapacious has been well applied to the members of this group. Fishes form their ordinary food, but they likewise devour coast and water birds, swallowing them with great ease and relish. In India they hunt eagerly after crabs, and everywhere voraciously feed upon the eggs of other birds whenever they can obtain them. Schilling tells us he has seen them fly to the breeding-places of Sea-fowl, and although at once attacked by the brooding parents, make their way to the nests quite regardless of the clamour, and help themselves without stint. Naumann and he visited a celebrated colony of this species at the northern extremity of the Island of Sylt, where they found their eggs laid upon the bare sand in little hollows, at a short distance from the water, the different broods not being more than two feet apart from each other. The eggs in shape and size much resembled those of tame Ducks. Their shells are smooth, but not shining, and their ground colour a dirty brownish white, marked with ash-grey and black; considerable difference, however, was observable even in those in the same nest. These birds begin to lay about the beginning of May; in Sylt the inhabitants regularly take the eggs, only allowing them to begin to brood eight or ten days before Midsummer. Should a man approach their nests, both male and female endeavour to defend it, and raise a terrible outcry. The young are clothed in down, of a greyish black above and white on the under surface; they soon run about, and for some days are assiduously fed with small fishes, which are brought to them by both parents.
The RIVER TERNS (Sterna) are distinguished from the preceding birds by their somewhat arched, moderately short beak, small short-toed feet, and deeply-forked tail; and by their frequent occurrence at the mouths or along the banks of rivers, or of inland streams or lakes. In size they are considerably smaller than the Caspian Terns, and their flight is much more graceful and Swallow-like, always exciting the admiration of the beholder.
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THE COMMON TERN.
The COMMON TERN (Sterna hirundo, Coloured Plate XXXVIII.), when in its adult plumage, closely resembles the Caspian Sea Swallow, but may be recognised by its inferior size, the grey colour of the under parts of the body, and by its red feet. In young birds the plumage of the back, like that of the preceding species, is transversely spotted with brown, but the feet are of a yellowish shade. The length of this species is from sixteen to seventeen inches; of these six and a half belong to the tail, the fork being four inches deep; the span of the wings is twenty-three inches. It is at present uncertain whether all River Terns are to be regarded as belonging to this species or not. Should they be found to do so, their habitat must extend throughout the whole north temperate zone, seeing that they are pretty equally distributed in the eastern and western hemispheres. They are met with more frequently than other Terns in the vicinity of rivers and lakes of fresh water. As these birds make regular migrations, they are only seen at their breeding-places in the summer, appearing during the last days of April or the beginning of May, and in July or August preparing for their departure. They spend the winter in the south of Europe, or in the north of Africa, where at that season they are very common. When on their journeyings they fly leisurely, and at a considerable elevation, from one sheet of water to another, generally following the course of streams and rivers, to which, if pressed by hunger, they repair, in order to obtain food and rest. Arrived at their destination, they settle themselves either in the vicinity of the sea, or near fresh water, without seeming to have any decided preference for either.
The Common Terns arrive in the south of Europe early in May, and progressing northwards, colonising as they go, visit Ireland, Scotland, and some of the adjacent islands. On inland waters the Terns do not congregate in great numbers. On the sea-shore, on the contrary, as the breeding season approaches, hundreds of them collect together and form large settlements. One of these settlements, on the coast of one of the Canary Islands, was visited by Bolle, who gives the following account of what he saw:—"The farther we advanced the more numerous became the flights of such pairs as we had disturbed, until at length we were obliged to proceed carefully to avoid treading on their eggs, so numerously did they lay around us on every side. Scarcely had we begun to collect some of the eggs in our hats and baskets, than up rose the whole multitude of breeding birds into the air, thousands in number, and overshadowed us like a great white cloud. Their shrieks were positively deafening, and the uproar was still further increased by the appearance of some other men at a little distance, who were likewise collecting eggs. From out of the living screen above us, many of these birds seemed to rush right down upon our heads, and these were probably those whose nests lay nearest to the place where we stood, and were consequently in the greatest danger of being plundered. After a little while, we retired to a distance, whence we could plainly see the different pairs, as they returned to their eggs, upon which the females immediately planted themselves, while their faithful spouses took their stations beside them. We did not leave them, however, till we had completely filled all our baskets with eggs, and this we accomplished in less than an hour. The men above alluded to, informed us that for a few weeks in the year, the place was constantly resorted to by the inhabitants, who eagerly collected the eggs, and that, nevertheless, the number of birds did not seem to diminish; the truth of this last assertion was indeed sufficiently evident." It not unfrequently happens that by some sudden flood in the rivers, or heavy storm at sea, the breeding-places of these Terns are completely inundated, and their eggs consequently destroyed. Should such an event occur early in the season, the parent birds will produce a second brood, but if it happens at a later period, their hope of progeny is at an end. Upon one occasion Naumann had an opportunity of witnessing a fair chase between the Common Tern and the agile Tree Falcon. The Tern did not[Pg 180] put into execution any of the usual manœuvres of water-birds, when trying to escape from pursuit, such as diving below the surface, but took boldly to her wings, and it was truly wonderful to see the adroitness with which all the efforts of the Falcon were foiled; whenever this terrible bird of prey stooped upon his intended victim, she slipped nimbly aside, and thus eluded the fatal clutch; or sometimes she would fall perpendicularly downwards, then mount above her foe towards the skies, rising higher and higher as he followed in pursuit, until at length the strength of the Falcon failed him, and he was forced to give up the chase. This Falcon is, however, very destructive to the young Terns, before their wings are strong enough to cope with those of their fleet foe. The eggs of this Tern are either yellowish grey, pale greenish brown or greenish blue, spotted with ash-grey or dark brown. Respecting the movements and noisy vociferations of the Common Terns, Macgillivray says, "When walking along the sandy shore you may see them coming up from a distance, increasing their speed as they approach, and then wheeling and plunging over you, until at last they fly off. Proceeding at a moderate height, they stop now and then, hover a moment, dip into the water, and secure a sand-eel or young coal-fish. Many attend on the fishermen, or others who are catching sand-eels for bait or food, to pick up those which fall from them disabled. On such occasions they are very vociferous, as they also are when they have fallen in with a shoal of fry. They never dive, but I have seen them alight on the water and swim a little, and sometimes a whole flock may be observed reposing on the placid bosom of the waters."
