BIRDS’ NESTS
“It is in the building of nests destined for the rearing of a family of
young ones that the bird shows in a remarkable way that wonderful
faculty which enables the little creature to accomplish, without
previous training, results that would seem to require the intervention
of reasoned experience.
“These adepts in bird-nest architecture have talents of the most varied
sort. There are diggers, who scoop out a hollow in the sand; miners,
who excavate a little cell to which a long and narrow passage gives
access; carpenters, who bore into the trunk of a worm-eaten tree;
masons, who work with mortar made of earth tempered with saliva;
basket-makers, who weave together small twigs and fine roots; tailors,
who with a filament of bark for thread and the beak for needle sew a
few leaves together into a cornet for holding the mattress on which the
young brood will rest; workers in felt, who make a fabric of down,
hair, or cotton, that rivals our own similar products; and builders of
fortresses, who protect their nest with an impenetrable thicket as a
rampart.
“The goldfinch, that pretty little red-headed bird which feeds on the
seeds of thistles, builds a wonderfully wrought nest in the fork of
some flexible branch. The outside is made of moss and the silky down of
thistle-seeds and dandelions, while the inside, artistically rounded,
is lined with a thick cushion of horse-hair, wool, and feathers.
“The chaffinch builds its nest in nearly the same way, but, more
mistrustful than the goldfinch, it covers the outside of its abode with
a layer of gray lichen which, merging with the lichen growing naturally
on the branch, serves to baffle the scrutiny of the bird-nest hunter.
“The window-swallow makes its nest in the corners of windows, under the
eaves of roofs, and in the shelter of cornices. Its building material
is fine earth, chiefly that left in little piles after its digestion by
earth-worms in fields and gardens. The swallow fetches it, a beakful at
a time, moistens it with a little viscous saliva to make it stick
together, and deposits it in courses, shaping the structure into a sort
of hemispherical bowl fastened to the wall and having a narrow mouth at
the top to allow the bird to squeeze through. Bits of straw embedded in
this masonry of earth serve to give it greater solidity. Finally, the
inside is upholstered with a quantity of fine feathers.
“The chimney-swallow chooses a similar situation for its nest and uses
the same building-materials, but the nest itself takes a different
form. Instead of a hemispherical structure entered by a very small
opening, it builds a cup-shaped nest, of no great depth and wide-open
at the top.
“Swallows like to live together in large numbers, so that their nests
are sometimes found touching one another in colonies of several
hundreds under the same cornice. Each pair recognizes unerringly its
own belongings and respects scrupulously the property of others, in
return for like respect paid to its own. There is among them a deep
sense of solidarity, and they render mutual aid with no less
intelligence than zeal.
“Sometimes it chances that a nest has hardly been finished when it
crumbles to pieces, the mortar used having been of poor quality, or
else the masons, with injudicious haste, having had too little patience
to let one course dry before laying another on top of it. At the news
of this mishap neighbors of both sexes hasten up to console the
unfortunates and to lend their aid in rebuilding. All apply themselves
to the task, fetching mortar of the first quality, and straws and
feathers, with such ardor and enthusiasm that in two days the nest is
completely rebuilt. Left to their own unaided efforts, the afflicted
pair would have needed a fortnight to repair the disaster.
“The golden oriole is one of the most beautiful birds of our clime.
About as large as the blackbird, it has plumage of a superb yellow,
except the wings, which are black. In building its nest it selects, in
some tall tree, a long and flexible bough with a fork at the end.
Between the two branches of this fork a hammock is woven for receiving
the nest. Strands of fine bark that has become shredded by long
exposure to wind and weather are used for this work of art. These
strands or cords pass from one side of the fork to the other, enlacing
them, crossing and recrossing, and thus forming a sort of pocket,
firmly fixed and securely hung.
“Broad blades of grass consolidate the structure. Then in this hammock
a mattress of the finest straw and having the form of an oval cup is
put together. The completed work bears some resemblance to those
elegant little wool-lined wicker baskets that are used as nests for
caged canaries.
“The long-tailed titmouse, remarkable for its excessive caudal
development, which constitutes more than half the total length of its
body, lives in the woods during the summer season, and comes into our
gardens and orchards only in winter. It is a small bird with a reddish
back and white breast. The stomach is tinged with red; the neck and
cheeks are white.
“Its nest is built sometimes in the fork of a high branch in a clump of
bushes, and sometimes in the dense underwood of a thicket, a few feet
from the ground; but it is most often attached to the trunk of a willow
or a poplar tree. Its shape is that of a very large cocoon, and its
entrance is at one side, about an inch from the top. On the outside it
is made of lichens like those that cover the tree, in order to blend
with the bark and deceive the eye of the passer-by. Fibers of wool
serve to hold all the parts securely together. To make the dome of the
nest rain-proof, it is formed of a sort of thick felt composed of bits
of moss and cobwebs. The inside resembles an oven with cup-shaped
bottom and very high top, and is furnished with a remarkably thick bed
of downy feathers, whereon repose from sixteen to twenty little birds,
arranged with careful order in the restricted space no larger, at the
most, than the hollow of one’s hand. By what miracle of parsimonious
economy do these twenty little ones with their mother manage to find
room for themselves in this tiny abode? And how in the world can tails
ever grow to such length there?
“The nest of the swinging titmouse is still more remarkable. In our
country this bird is hardly ever found except on the banks of the lower
Rhone. It hangs its nest very high, on the tip-end of some swaying
branch of a tree at the water-side, so that its brood is gently rocked
by the breeze sweeping over the river.”
“Why, I should think,” put in Emile, “there would be danger of the
young birds’ spilling out of such a swinging nest.”
“Not at all,” replied his uncle. “The shape of the nest provides
against that. It is a sort of oval purse about as large as a
wine-bottle, with a small opening at one side, near the top. This
opening is prolonged like the neck of a bottle and will at the utmost
admit one’s finger. To pass through so narrow an entrance, the
titmouse, small as it is, must stretch the elastic wall, which yields a
little and then contracts again. This purse, as I have called it, is
made of the cotton-like flock that comes from the ripening seeds of
poplars and willows in May. The titmouse gathers these bits of down and
weaves them together with a woof of wool and hemp. The fabric thus
obtained is not unlike the felt of a cheap hat.
“It would be useless to seek an explanation of the bird’s astonishing
success in manufacturing, with no implements but beak and claws, a
textile that man’s skilful hand, left to its own resources, would be
unable to produce; and this success the bird achieves with no previous
apprenticeship, without hesitation and without ever having seen the
thing done by others. At the very first trial the titmouse surpasses in
its art our weavers and fullers.
“The top of the nest includes in its thickness the end of the branch
from which it hangs, with the terminal twigs of that branch, which
serve as framework for the nest’s vaulted roof, while the foliage
projecting through the sides of the nest protects it with its shade.
Finally, to secure greater firmness of support, a cordage of wool and
hemp is passed around the branch and interlaced with the felt of the
nest. The inside of this hanging habitation is lined with down of the
finest quality from the poplar tree.
“Are you acquainted with the troglodyte or, as it is more commonly
called, the wren? It is the smallest of our birds, and it too is a
master in the art of nest-building. Clothed in reddish brown, with
drooping wing and upturned beak and tail, it is always frisking,
hopping, and twittering,—teederee, teeree, teeree. Every winter it
comes flying about our houses, frequenting the wood-pile, inspecting
holes in the wall, and prying into the densest thickets. At a distance
it might be mistaken for a small rat.
“In summer it lives in the pathless woods. There, under the shelter of
some big root that lies close to the ground and is covered with a thick
fleece of moss, it builds a nest patterned after that of the swinging
titmouse. Its materials are bits of moss, selected for the purpose of
making the nest undistinguishable in appearance from that to which it
is attached. The bird gathers these materials and works them into the
shape of a large, hollow ball with a very small opening on one side.
The interior is upholstered with feathers.
“The magpie fixes its dwelling in the top of some lofty tree whence, as
from an observatory, it can spy from afar the approaching enemy. At the
juncture of a number of branching twigs that offer adequate support it
plants its nest, constructed of interlacing flexible sticks with a
floor of tempered earth. Fine rootlets, blades of grass, and a few
tufts of down form the bedding for the prospective brood.
“So far there is nothing to differentiate the structure from ordinary
nests; but now we behold the exhibition of a special talent on the
magpie’s part. The entire nest, and more particularly its upper part,
is surrounded by a thick rampart, a sort of fortified enclosure
composed of thorny twigs securely intertwined. One would take the whole
thing for a shapeless mass of brushwood. Through this rampart, on the
side that is most strongly defended, an opening is left of just
sufficient size to admit of the mother’s entrance and exit. It is the
only door to the aërial fortress.
“Let us turn now to a bird that builds upon piling. It is a warbler of
large size, called the great sedge-warbler or river-thrush. It selects
a cluster of four or five reeds that project above the surface of a
pond, with their stalks rooted in the mud under the water and growing
near together. These slender piles, the tops of which the bird brings
into such proximity as may be desired and fastens with connecting
strands, are made to bear an interlacing of flexible materials, such as
rushes, bark-fibers, and long blades of grass. It is a basket-weaver’s
job, with a framework of reeds as a basis for the structure. Finally,
in this basket, which is made much longer than wide, is placed the nest
proper, a warm little bed of cotton-like down, spiders’ webs, and wool.
“But this abode resting on piles above the water is exposed to two
dangers,—the swaying of the reeds which, bent over by the wind, might
incline the nest so that it would spill its contents either of eggs or
of young birds; and secondly, the spring freshets, which might rise so
high as to submerge the nest. These dangers, however, have been
foreseen by the bird. The nest is very deep, and furthermore the edges
of the opening bend inward and form a parapet. In this way is avoided
the risk of a fall when the reeds that bear the nest are swayed by the
wind. Finally, since the sedge-warbler is at liberty to build her nest
at any desired height above the surface of the pond, she places it
always high enough to be beyond the reach of the rising water, even in
great floods. One suspects the bird of being able to foresee, months in
advance, the coming inundation; for she builds her nest at a greater or
less elevation according to the high-water mark destined later to be
reached by the surface of the pond.
“The cisticola is a small warbler very common in the marshes of
Camargue, at the mouth of the Rhone. Its nest is placed in the middle
of a cluster of grass and rushes, and takes the form of a purse with a
small round opening. Fine dry leaves form the bed on which the eggs
rest, while other and larger leaves are fixed all around it to form an
enclosure.
“For this work the bird turns tailor, cutting the leaves and lapping
them over one another. Along the border of each leaf it punches holes
with the point of its beak and through these holes it passes one or
more threads made of cobwebs and the down from certain plants. Its
distaff for holding the thread—namely, the beak—does not admit of using
very long strands; hence the needleful, so to speak, goes only twice
or, at most, three times from one leaf to the next one. But no matter;
the sewing is strong enough to fasten the whole into a sort of purse
which keeps out the rain.
“The orthotomus, or grass-warbler, a small bird of India, is an even
more skilful tailor, and in fact is commonly known as the tailor-bird.
It selects two large leaves, still living and attached to the branch on
which they grew. These are brought together, with their longer edges
touching, and are sewed border to border with strong cotton thread made
by the bird’s beak. The seams run only half the length of the leaves,
in such a manner that the two together, hanging down as they do, form a
conical sac with its mouth upward. In this sac the nest is placed,
hidden by its protecting envelope, which so blends with the rest of the
foliage that even after a person has once found the nest he can with
difficulty find it again.
“In South Africa there is a bird scarcely larger than our swallow and
known as the social republican from its living in large societies with
one nest in common. This nest, a sort of bird village, is shaped like
an enormous mushroom, spreading out all around the trunk of a tree,
which serves as its stalk, while the lower branches also furnish their
support. This colossal edifice is of such bulk and weight as to make a
wagon-load, and if one wishes to see the interior structure it must be
chopped to pieces with an axe. It is formed wholly of dry grass
arranged much like the thatch on our rustic roofs.
“Indeed, this structure, built at public expense by all the associated
birds, is nothing but a roof, a dome, destined to shelter the real
nests, which are attached to the inside of the thatched covering. Here
are to be found a multitude of round holes presenting all together
somewhat the appearance of a honeycomb. Each hole gives access to a
small cell, a veritable nest and the separate work of a single pair.
The grass roof, then, is built in common by the whole society, after
which each family provides for its exclusive use a little apartment
attached to the lower side of the roof. The number of inhabitants may
reach as high as a thousand.”