SELBORNE, _Nov._ 20_th_, 1773.
Dear Sir,--In obedience to your injunctions I sit down to give you some
account of the house-martin, or martlet; and if my monography of this
little domestic and familiar bird should happen to meet with your
approbation, I may probably soon extend my inquiries to the rest of the
British hirundines--the swallow, the swift, and the bank-martin.
A few house-martins begin to appear about the 16th April; usually some
few days later than the swallow. For some time after they appear the
hirundines in general pay no attention to the business of nidification,
but play and sport about, either to recruit from the fatigue of their
journey, if they do migrate at all, or else that their blood may recover
its true tone and texture after it has been so long benumbed by the
severities of winter. About the middle of May, if the weather be fine,
the martin begins to think in earnest of providing a mansion for its
family. The crust or shell of this nest seems to be formed of such dirt
or loam as comes most readily to hand, and is tempered and wrought
together with little bits of broken straws to render it tough and
tenacious. As this bird often builds against a perpendicular wall
without any projecting ledge under, it requires its utmost efforts to get
the first foundation firmly fixed, so that it may safely carry the
superstructure. On this occasion the bird not only clings with its
claws, but partly supports itself by strongly inclining its tail against
the wall, making that a fulcrum; and thus steadied, it works and plasters
the materials into the face of the brick or stone. But then, that this
work may not, while it is soft and green, pull itself down by its own
weight, the provident architect has prudence and forbearance enough not
to advance her work too fast; but by building only in the morning, and by
dedicating the rest of the day to food and amusement, gives it sufficient
time to dry and harden. About half an inch seems to be a sufficient
layer for a day. Thus careful workmen, when they build mud-walls
(informed at first, perhaps, by this little bird), raise but a moderate
layer at a time, and then desist, lest the work should become top-heavy,
and so be ruined by its own weight. By this method in about ten or
twelve days is formed a hemispheric nest with a small aperture towards
the top, strong, compact, and warm; and perfectly fitted for all the
purposes for which it was intended. But then nothing is more common than
for the house-sparrow, as soon as the shell is finished, to seize on it
as its own, to eject the owner, and to line it after its own manner.
After so much labour is bestowed in erecting a mansion, as Nature seldom
works in vain, martins will breed on for several years together in the
same nest, where it happens to be well sheltered and secure from the
injuries of weather. The shell or crust of the nest is a sort of rustic
work, full of knobs and protuberances on the outside; nor is the inside
of those that I have examined smoothed with any exactness at all; but is
rendered soft and warm, and fit for incubation, by a lining of small
straws, grasses, and feathers, and sometimes by a bed of moss interwoven
with wool. In this nest they tread, or engender, frequently during the
time of building; and the hen lays from three to five white eggs.
At first when the young are hatched, and are in a naked and helpless
condition, the parent birds, with tender assiduity, carry out what comes
away from their young. Was it not for this affectionate cleanliness the
nestlings would soon be burnt up, and destroyed in so deep and hollow a
nest, by their own caustic excrement. In the quadruped creation the same
neat precaution is made use of, particularly among dogs and cats, where
the dams lick away what proceeds from their young. But in birds there
seems to be a particular provision, that the dung of nestlings is
enveloped in a tough kind of jelly, and therefore is the easier conveyed
off without soiling or daubing. Yet, as nature is cleanly in all her
ways, the young perform this office for themselves in a little time by
thrusting their tails out at the aperture of their nest. As the young of
small birds presently arrive at their ἡλικία, or full growth, they
soon become impatient of confinement, and sit all day with their heads
out at the orifice, where the dams, by clinging to the nest, supply them
with food from morning to night. For a time the young are fed on the
wing by their parents; but the feat is done by so quick and almost
imperceptible a flight that a person must have attended very exactly to
their motions before he would be able to perceive it. As soon as the
young are able to shift for themselves, the dams immediately turn their
thoughts to the business of a second brood; while the first flight,
shaken off and rejected by their nurses, congregate in great flocks, and
are the birds that are seen clustering and hovering on sunny mornings and
evenings round towers and steeples, and on the roofs of churches and
houses. These congregatings usually begin to take place about the first
week in August, and therefore we may conclude that by that time the first
flight is pretty well over. The young of this species do not quit their
abodes altogether; but the more forward birds get abroad some days before
the rest. These approaching the eaves of buildings, and playing about
before them, make people think that several old ones attend one nest.
They are often capricious in fixing on a nesting-place, beginning many
edifices, and leaving them unfinished; but when once a nest is completed
in a sheltered place, it serves for several seasons. Those which breed
in a ready finished house get the start in hatching of those that build
new by ten days or a fortnight. These industrious artificers are at
their labours in the long days before four in the morning. When they fix
their materials they plaster them on with their chins, moving their heads
with a quick vibratory motion. They dip and wash as they fly sometimes
in very hot weather, but not so frequently as swallows. It has been
observed that martins usually build to a north-east or north-west aspect,
that the heat of the sun may not crack and destroy their nests; but
instances are also remembered where they bred for many years in vast
abundance in a hot stifled inn-yard against a wall facing to the south.
Birds in general are wise in their choice of situation; but in this
neighbourhood every summer is seen a strong proof to the contrary at a
house without eaves in an exposed district, where some martins build year
by year in the corners of the windows. But, as the corners of these
windows (which face to the south-east and south-west) are too shallow,
the nests are washed down every hard rain; and yet these birds drudge on
to no purpose from summer to summer, without changing their aspect or
house. It is a piteous sight to see them labouring when half their nest
is washed away and bringing dirt . . . "_generis lapsi sarcire ruinas_."
Thus is instinct a most wonderful unequal faculty; in some instances so
much above reason, in other respects so far below it! Martins love to
frequent towns, especially if there are great lakes and rivers at hand;
nay, they even affect the close air of London. And I have not only seen
them nesting in the Borough, but even in the Strand and Fleet Street; but
then it was obvious from the dinginess of their aspect that their
feathers partook of the filth of that sooty atmosphere. Martins are by
far the least agile of the four species; their wings and tails are short,
and therefore they are not capable of such surprising turns and quick and
glancing evolutions as the swallow. Accordingly they make use of a
placid easy motion in a middle region of the air, seldom mounting to any
great height, and never sweeping long together over the surface of the
ground or water. They do not wander far for food, but affect sheltered
districts, over some lake, or under some hanging wood, or in some hollow
vale, especially in windy weather. They breed the latest of all the
swallow kind: in 1772 they had nestlings on to October 21st, and are
never without unfledged young as late as Michaelmas.
As the summer declines the congregating flocks increase in numbers daily
by the constant accession of the second broods, till at last they swarm
in myriads upon myriads round the villages on the Thames, darkening the
face of the sky as they frequent the aits of that river, where they
roost. They retire, the bulk of them, I mean, in vast flocks together
about the beginning of October, but have appeared of late years in a
considerable flight in this neighbourhood, for one day or two, as late as
November 3rd and 6th, after they were supposed to have been gone for more
than a fortnight. They therefore withdraw with us the latest of any
species. Unless these birds are very short-lived indeed, or unless they
do not return to the districts where they are bred, they must undergo
vast devastations somehow and somewhere; for the birds that return yearly
bear no manner of proportion to the birds that retire.
House-martins are distinguished from their congeners by having their legs
covered with soft downy feathers down to their toes. They are no
songsters, but twitter in a pretty inward soft manner in their nests.
During the time of breeding they are often greatly molested with fleas.