"Omnibus animalibus reliquis certus et uniusmodi, et in suo cuique
genere incessus est: aves solae vario meatu feruntur, et in terra, et
in aere."
SELBORNE, _Aug._ 7_th_, 1778.
Dear Sir,--A good ornithologist should be able to distinguish birds by
their air as well as by their colours and shape, on the ground as well as
on the wing, and in the bush as well as in the hand. For, though it must
not be said that every species of birds has a manner peculiar to itself,
yet there is somewhat in most _genera_ at least, that at first sight
discriminates them, and enables a judicious observer to pronounce upon
them with some certainty. Put a bird in motion
"--Et vera incessu patuit--"
Thus kites and buzzards sail round in circles with wings expanded and
motionless; and it is from their gliding manner that the former are still
called in the north of England gleads, from the Saxon verb glidan, to
glide. The kestrel, or wind-hover, has a peculiar mode of hanging in the
air in one place, his wings all the while being briskly agitated. Hen-
harriers fly low over heaths or fields of corn, and beat the ground
regularly like a pointer or setting-dog. Owls move in a buoyant manner,
as if lighter than the air; they seem to want ballast. There is a
peculiarity belonging to ravens that must draw the attention even of the
most incurious; they spend all their leisure time in striking and cuffing
each other on the wing in a kind of playful skirmish, and, when they move
from one place to another, frequently turn on their backs with a loud
croak, and seem to be falling to the ground. When this odd gesture
betides them, they are scratching themselves with one foot, and thus lose
the centre of gravity. Rooks sometimes dive and tumble in a frolicsome
manner; crows and daws swagger in their walk; wood-peckers fly _volatu
undoso_, opening and closing their wings at every stroke, and so are
always rising or falling in curves. All of this genus use their tails,
which incline downward, as a support while they run up trees. Parrots,
like all other hooked-clawed birds, walk awkwardly, and make use of their
bill as a third foot, climbing and descending with ridiculous caution.
All the _gallinoe_ parade and walk gracefully, and run nimbly, but fly
with difficulty, with an impetuous whirring, and in a straight line.
Magpies and jays flutter with powerless wings, and make no despatch;
herons seem encumbered with too much sail for their light bodies, but
these vast hollow wings are necessary in carrying burdens, such as large
fishes and the like; pigeons, and particularly the sort called smiters,
have a way of clashing their wings the one against the other over their
backs with a loud snap; another variety, called tumblers, turn themselves
over in the air. Some birds have movements peculiar to the season of
love. Thus ringdoves, though strong and rapid at other times, yet in the
spring hang about on the wing in a toying and playful manner; thus the
cock-snipe while breeding, forgetting his former flight, fans the air
like the wind-hover; and the green-finch in particular, exhibits such
languishing and faltering gestures as to appear like a wounded and dying
bird; the king-fisher darts along like an arrow; fern-owls, or
goat-suckers, glance in the dusk over the tops of trees like a meteor;
starlings, as it were, swim along, while missel-thrushes use a wild and
desultory flight; swallows sweep over the surface of the ground and
water, and distinguish themselves by rapid turns and quick evolutions;
swifts dash round in circles; and the bank-martin moves with frequent
vacillations like a butterfly. Most of the small birds fly by jerks,
rising and falling as they advance. Most small birds hop; but wagtails
and larks walk moving their legs alternately. Skylarks rise and fall
perpendicularly as they sing; woodlarks hang poised in the air; and
titlarks rise and fall in large curves, singing in their descent. The
white-throat uses odd jerks and gesticulations over the tops of hedges
and bushes. All the duck-kind waddle; divers and auks walk as if
fettered, and stand erect on their tails: these are the _compedes_ of
Linnaeus. Geese and cranes, and most wild fowls, move in figured
flights, often changing their position. The secondary _remiges_ of
Tringae, wild-ducks, and some others, are very long, and give their
wings, when in motion, a hooked appearance. Dabchicks, moorhens, and
coots, fly erect, with their legs hanging down, and hardly make any
despatch. The reason is plain, their wings are placed too forward out of
the true centre of gravity, as the legs of auks and divers are situated
too backward.