the manner in which their power of swimming becomes more and more
complete. In the Sea-fliers we shall recognise the tyrants of the ocean,
seeing that in their presence the swimming birds, whether inhabitants of
the coast or children of the wave are subservient. The great character
whereby the _Longipennes_ are distinguished is the enormous development of
their wings, while that of their feet remains comparatively in abeyance.
Some of them, it is true, are well able both to swim and to walk, but
their special adaptation is for flight. Their power of flying is supreme,
and in this they are surpassed by no other birds. As to their general
structure, there is a great similarity between the different races. Their
body is powerful, their neck short, and their head of moderate size.
Their beak, which is of medium length, is compressed at the sides and
sharp-pointed or hooked at the end; in conformity with this structure, the
upper mandible is more or less arched, while the under jaw at a little
distance from its apex, is strengthened by an angular enlargement. Their
feet are feeble in proportion to the size of their bodies, and only webbed
upon the three anterior toes; moreover, even upon these the webs are often
very imperfectly developed. The wings are always long, and sharp-pointed,
more or less narrow and proportionately very large; their tail is of
moderate dimensions, either truncate, greatly rounded, pointed, or forked
at the extremity, and usually composed of twelve feathers. The general
plumage is very thick and rich, but not particularly well-furnished with
down; its colour is much varied, and changes with the age of the bird and
at different seasons. In all the above characters and in many others that
might be adduced from an examination of their internal structure, these
birds differ from the Swimmers in so many particulars that they cannot be
considered as in any way belonging to the same order.
The domain of the Sea-fliers is the ocean, their territory the wide world.
Some families seem more especially to frequent coasts, others prefer fresh
water to the salt sea, but these are mere exceptions. Sweeping continually
over the waves, or skimming in the proximity of coasts, they wander over
the sea and circle round the globe. By one tie only are they bound to the
dry land, and that is, their affection for their offspring. They lay their
eggs upon the land, and there watch over their young brood until their
wings attain sufficient strength to enable them to join their brethren in
the air; the rest of their time is for the most part devoted to the sea,
upon which they sometimes repose, or, in exceptional cases, sleep upon
the shore. Their flight is longer sustained than that of the Swallows or
Swifts, or even of the Humming-birds, for they fly not only during the
whole day but often likewise throughout the night. It is to this untiring
energy and constant restlessness that we must attribute the boundless
range over which particular species spread themselves. Some of them indeed
have literally a world-wide distribution, and visit every climate between
the equator and the polar seas. Others again, restrict their wanderings,
or migrations, or flights, or whatever the reader may choose to call them,
either within more or less definite regions, or within certain degrees of
latitude; it must, however, be kept in mind that these boundaries are not
coasts or countries, but whole continents and oceans.
All Sea-fliers are divers, but, owing to the thickness of their plumage,
some are less capable than others of plunging far beneath the surface.
They generally fly over the waves at a certain altitude, disporting
themselves in the sunshine should the weather be fine, or battling with
the elements during a storm. While flying, their attention is anxiously
bent upon the sea beneath, on the look-out for food, upon which, when
discovered, they instantly dart down, some of them with the straightness
and rapidity of an arrow, others more leisurely, while some, before they
seize their prey, settle down and swim. All are equally rapacious, whether
they catch food for themselves or rob other birds of their hard-earned
booty, whether they devour living victims or content themselves with
feeding, like the Vultures, upon carrion. Whatever the sea presents for
their acceptance they greedily swallow. In their mode of breeding these
birds very much resemble each other. Their nests are generally placed
upon the ground, sometimes in wild mosses and swamps, sometimes on ledges
or projections of rocks, and in the holes and excavations of the soil.
Occasionally they select precipitous cliffs and mountains, more rarely
trees; some lay but one egg, others two, three, or four. All show much
attention to their mates and offspring. The young are at once introduced
to their future element, where they soon learn to catch their own food.
* * * * *
The TERNS, or SEA SWALLOWS (_Sternæ_), are a race of middle-sized or small
slenderly-built birds. Their beak is of about the same length as the head,
hard, straight, or gently arched towards the tip, both in the upper and
lower mandible. The feet are feeble, and provided with toes united by a
short or deeply-excavated web, and furnished with slightly-curved sharp
claws. The wings are long, narrow, and sharp-pointed, the first quill
being the longest; the tail, which is of medium length, consists of twelve
feathers, and is more or less forked. The thick, soft, close plumage is
coloured light blue, black, and white, and varies but little either with
the sexes, age, or season of the year. The Terns are very extensively
distributed, inhabiting every zone; still they appear to prefer warm
and temperate climates to the colder regions, only visiting the latter,
indeed, for a short time during the year. The members of this group live
both upon the sea and fresh water, and during their wanderings follow the
windings of coasts and the courses of rivers; some species prefer flat,
bare shores, others resort to localities rich in vegetation, while others,
again, delight in the neighbourhood of woods. All are exceedingly active,
and from sunset to sunrise are constantly on the wing; their nights are
passed on dry land, but they apparently require less repose than any of
their kindred. They walk badly, and when on the ground hold their body in
a horizontal position, slightly depressed in front, so that the tips of
their long sabre-like wings are higher than their head, which is kept in a
retracted position. In the water they swim like corks, their little feet
being almost incapable of assisting them in that element; on the other
hand, their powers of flight are wonderful, and will bear comparison in
every respect with those of the Swallow. When not in haste they move their
wings with slow wide-spreading strokes, and thus glide onwards through the
air in a gently undulating line; but if urged to speed they beat the wind
with powerful rapid jerks, and skim along with indescribable velocity. In
fine weather they disport themselves almost after the manner of Swallows,
sweeping round and round in broad circles, and performing a variety of
elegant curves and graceful evolutions; but in a storm their energies
seem roused to the utmost, and they may then be seen battling untiringly
against the gale. Generally they fly very low over the surface of the
water, rising and sinking as the waves heave and fall, till suddenly,
with close-shut wings, they dart obliquely into the sea, sinking so deep
that they almost disappear, but, immediately rising again, they shake
their wings and recommence their devious course over the billows. In this
manner they fly over a vast extent of water during the day, but however
widely they may wander, return again and again to the same track, and
never remove far from the locality whence they started. The disagreeable
shrieking cry uttered by these birds varies but little in different
species. Although the Terns are very sociable in their intercourse with
their own kind, they appear to take but little heed of the rest of their
feathered companions, even when, as is often the case, they associate with
them in search of food. The diet of the Sea Swallows consists principally
of fishes and a variety of creatures met with in the sea, their prey
being always taken when on the wing. These birds are strictly monogamous:
a few weeks before the commencement of the breeding season they begin to
assemble in the vicinity of their meeting-place, returning year after year
to the same locality. Such species as inhabit the sea-shore generally
select coral-banks, islands, or long spits of bare sand for this purpose,
while such as settle inland seek out similar, but less barren spots, in
the vicinity of swamps and marshes, the various species usually breeding
apart from each other. Such as resort to morasses lay their eggs in a
mere depression of the ground. Their unpretending apologies for a nest
are sometimes isolated, sometimes so crowded together as literally to
cover the ground so thickly, that the brooding birds have all to sit with
their heads in one direction, and a man cannot pass between them without
crushing the eggs of contiguous nests. Even such species as resort to
trees construct nothing in the shape of a nest, but deposit their eggs
in chinks of the bark or inequalities of the branches. Most of the Terns
lay three eggs, others two, whilst those that breed on trees deposit but
one. The male and female brood alternately; during the heat of the day,
however, they leave their eggs to be kept warm by the sun. The young are
hatched in about a fortnight or three weeks, and make their appearance
clad in down; they leave the hollow that has served as a nest on the day
of their birth, and run at once down to the water's edge, quite as fast as
their parents, by whom they are anxiously and carefully tended.
[Illustration: _Plate 38, Cassell's Book of Birds_
STERNA HIRUNDO ____ COMMON TERN
(_about 1/3 Nat. size_)]
[Illustration: THE CASPIAN TERN (_Sylochelidon Caspia_).]
* * * * *
The RAPACIOUS TERNS (_Sylochelidon_) are the largest of the Sea Swallows,
and distinguishable 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.
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 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."
[Illustration: TERNS AND THEIR NESTS.]
THE LESSER TERN.
The LESSER TERN (_Sternula minuta_) has been considered by some
ornithologists as the representative of a distinct sub-family, although
it only differs from the preceding species in its inferior size,
proportionately strong short beak, the deeply-incised web of its foot, and
the shallow furcation of its tail. In this bird the forehead and under
side are white, the upper head and nape black, the mantle and wings dark
green. The eye is brown, the beak yellow, with black point, and the foot
clay-yellow. The length of this bird is eight inches and a half; breadth
nineteen to twenty inches; length of wing seven, and tail three inches.
The young are spotted like the preceding species. The range of the Lesser
Tern extends over Europe, Asia, Africa, and America, from 24° to 58° north
latitude. In Brazil it is replaced by a somewhat larger species. The
Lesser Tern makes its appearance in Great Britain about May, and after
having reared its young, resumes its wandering habits about the end of
July or August. It is, however, a slow traveller, and only reaches the
lakes and streams of North Africa in the autumn; its migrations from North
Asia and North America are conducted in a similar manner. This species
prefers fresh to salt water, and chiefly frequents large rivers without,
however, altogether withdrawing from the sea-shore. The first requisite
for its accommodation would seem to be a little island or bed in a stream,
covered with gravel or sand, for where these are wanting it is never to
be found. Although the two or three eggs of the Lesser Tern (which have
a stone-coloured shell marked with grey, or reddish brown) are usually
merely deposited in a slight depression of the ground above high-water
mark, Audubon states that some pairs that he found breeding on the coasts
of Labrador had formed very snug nests composed of short fragments of
moss, well matted together, while those on the island near the Bay of
Gaveston had laid their eggs on dry drifted weeds, which appeared to have
been gathered by them for this purpose. The same author tells us that the
common note of this bird resembles that of the Barn Swallow when disturbed
about its nest, and is at times as smartly and rapidly repeated. The
following very pretty description of the light and beautiful movements of
this Tern whilst on the wing is from the pen of Mr. Macgillivray:--"In
the elegance of its buoyant flight as it skims over the waters or shoots
on its way to and from its breeding-place, the tiny creature must be
an object of admiration to every lover of nature. You may see a pair
coming up from a distance flying at the height of a few yards over the
waves, their long wings winnowing the air and impelling them in starts,
as it were, as they wend their way in undulating and wavering movements.
Suddenly their flight is arrested over a large pool left on the sands by
the retiring tide; with quick beats of their wings, they hover stationary,
or but slightly shifting place, and with downward-pointed bill seem intent
on something which they perceive in the water. One drops, but not like a
stone, dips, but with upraised wings, and rises with a small fish in its
bill. The other is similarly successful. Onward they proceed, now and then
emitting a shrill cry and with gentle beats of their wings. Far ahead is
a flock engaged in picking up their prey, and onward they speed to join
their kindred." Although these birds usually swallow their prey whilst in
the air they are occasionally seen to alight upon the ground with their
booty, and there devour it piecemeal.
* * * * *
The WATER SWALLOWS (_Hydrochelidon_) constitute a well-defined group
belonging to the Tern family. These birds are powerfully built and of
elegant appearance; their beak is feeble, tarsus high, toes long and
united by a deeply-incised web. The wing is very long, tail short and but
little forked. The general plumage, which is soft and thick, is during the
breeding season principally black; this latter character, however, varies
much according to the age of the bird and season of the year.
THE BLACK MARSH TERN.