Evening star., 1909-03-04
SOME BIRDS BEAKS.
How They Are Adapted to the Gath
ering of Food.

ering of Food.
From the Westminster Gazette.
Besides the few extraordinary examples
of birds beaks dealt with in our last
weeks column of Mature Notes." there
are many other very striking modifica-
tions that bear directly on the different
methods of gathering food. In reviewing
some of these examples one cannot help
being struck by the fact that in some
cases nature has devised very widely diff
fering implements that serve one and the
same purpose. A notable instance Of
this is seen in the beak of the shoveler
duck and that Of the flamingo. Both these
birds obtain their food by sitting out
the mud Of shallow Hgoons and waters.
and their beaks are both provided with
soft transverse lamellae-to use. perhaps.
rather exaggerated comparison-not
quite unlike the whalebone grill of the
toothless cetaceans, to assist in the sitting
of the particles of disturbed mud and
weed: but whereas the beak of the duck
is somewhat fiattened and spatulate in
form, that of the fiamingo is bulky and
decidedly Roman in character. for the
beak takes d Suddes downward bend in
the middle. as if it had been broken: SO
much decurved is it, indeed that the bird.
in order to sift the watery ooZe. is obliged
to do so with the crown of the head held
downward. the top of the beak on the
surface Of the ground, and with eyes
looking backward between the long legs
Although we see that the method of feed
ing is the same In the two species. and
both forms of beaks are provided with
special facilities for sitting their food by
means of the transverse lamellae nature
recognized that the spatulate form would
be useless for the lOng-legged. .long- g-necked
fiamingo and the arched beak worse than
useless for the short-necked squat shovel
er ducks. Such errors of nature are not
allowed to be. and any tendency toward
defect or bad development Is almost in
stantly checked, for the individual i'm
which it appears is Immediately put at
a disadvantage in the keen struggle for
existence. So we may be pretty sure that
however grOtesque any modification may
be- or however little we understand the
and continuance of that species show
only too clearly that nature has discov-
cred for herself the proper equipment
The bill of the mersanser. a fish-eating
diving species of duck, shows a very
marked popularity. for both the lower
and upper mandibles are provided with
numerous tooth-like serrations directed
backward. These are not teeth In the
sesses teeth, but merely horny denticula-
tions. It is obvious that owing to these
serrations there Is less chance of any slip
perry denizen OF the waters wrggltng out
of the grip of its captor. The bills of
the nightjars are almost absent, as is also
that of the swift. Their cape. however.
is enormous for they rely on catching
their insect prey during their aerial evo-
lutions. for which purpose a bill of small
est dimensions and a cape of the biggest
with the extra assistance of numerous
stiff briStles at either side are invaiu-
able. No one who examined the strong.
hooked beak of a bird Of prey could fail
to admire the adaptability Of this shape
for III OYSTER.
catcher, which wanders ''long-shore" with
its shrill whistle, could not have been
better equipped than with its fairly long
but straight, stout beak for prizing linn
pets off the rocks or breaking open mus
sci shells. The curlew of our shores, which
lives by probing in the mud and sand
for worms and molluscs, as well as pick
ing up fairly OmnivorouS diet, Is re-
marka BILE for its long. curved beak; while
the avocet. which does not PROBE. but
merely picks up its food which Is SWIM
ming or floating on shallow water, pos
sesses a long delicate beak curved up
ward, exactly the reverse OF that Of the
curlew.
The SKINNER of North America Is
peculiar form, for this bird. which gath
ers its food from the surface Of the
water, has the lower mandible much long.
er than the upper the lower one being
so thin laterally that it almost resembles
a knife blade. while the shorter upper
mandible Is capable of a certain vertical
In gathering its food while
ON the wing the lower knife-like mandi-
BILE cuts through the surface Of the water,
making the least disturbance possible.