THE BIRD’S BEAK
“There are many other small birds that live almost exclusively on
insects, and in so doing render a great service to agriculture. A full
account of them all would take too long; and, besides, you are familiar
with the greater number, seeing them daily in the woods, fields,
orchards, and gardens. I will confine myself, therefore, to the chief
difference between insect-eaters and birds that live on seeds and
grain; and then a glance at some of the habits of the most important
species will complete our rapid review.
“The food of small birds falls into two classes, seeds and insects.
Certain birds require millet, hemp-seed, pips, and similar seeds of all
kinds, while others need grubs, larvæ, insects. The choice of one or
the other sort of food is determined by the shape of the beak, just as
a mammal’s diet depends on the structure of the animal’s teeth. The
molars of the horse and the ox call for forage to grind under their
flat, wide crowns; but those of the wolf and the cat, with their sharp
edges, need flesh to cut to pieces. In the same manner the bird’s beak,
according to whether it is shaped this way or that, whether large or
small, thick or slender, strong or weak, requires hard seeds that crack
under the mandibles and in opening yield their kernels, or the tender
grub that is swallowed without having to be crushed. Show me your
teeth, we said to the mammal, and I shall know what you eat. Show me
your beak, we might now say to the bird, and I shall know whether you
live on insects or seeds.
“The beak of the bird that lives on seeds or grain—that is, the
granivorous bird—is thick, conical, wide at the base, and strong in
proportion to the hardness of the seeds it has to crack open; but the
beak of the bird that lives on insects—that is, the insectivorous
bird—is thin, slender, delicate, and weak in proportion to the softness
of the insects it catches. In our everyday speech we note this
difference by applying to the small granivorous birds the general
designation grosbeak, while the insect-eaters are often called
slender-beaked birds. Let us remember these two expressive words and
formulate the general principle thus: Seeds for the grosbeak, worms for
the slender beak.
“And now without further delay we will put the rule into practice. Here
is a bird whose diet is perhaps a matter of uncertainty to you. If I
ask you what, to judge from the shape of its beak, is its customary
food, shall you be at a loss how to reply?”
“That strong beak, so wide at the base, must be meant for crunching the
very hardest seeds,” was Jules’s opinion.
“Yes,” Emile chimed in, “that bird certainly lives on seeds; it is
written all over its big face.”
“It is, indeed, a consumer of all kinds of seeds; it is the greenfinch
of our copses, greenish underneath and with a yellow border to its
tail. The dominant color of its costume, green mixed with yellow, has
given it the name of greenfinch. And this one?”
“Seeds for the grosbeak, worms for the slender beak,” repeated Emile.
“The beak has no strength; it is rather long but thin; the bird is an
insect-eater.”
“And one of the greediest, for it belongs to the family of warblers,
those delightful songsters that would be afraid of getting hoarse if
they ate dry, farinaceous grain. To keep their vocal cords flexible
these artists must have the gentle lubricant furnished by caterpillars
and the succulent flesh of larvæ. They take good heed not to touch
coarse seeds, which would injure the voice. This bird is the
reed-warbler, which lives on dragon-flies, small June-bugs, mosquitoes,
and horse-flies, snapping them up on the wing. It builds its nest among
the reeds in willow thickets. It is reddish brown above and yellowish
white underneath.
“Finally, let us look at this third one.”
“Another slender beak,” said Emile; “another insect-eater.”
“Yes; you see it isn’t difficult. The bird has three names among us:
washerwoman, wagtail, and little shepherdess. Washerwoman, because it
frequents the waterside in company with those that wash linen; wagtail,
because it wags its tail at every step it takes; and little
shepherdess, because it likes the society of shepherds and flocks. It
is ash-colored above, white underneath, and black on the back of the
head and also on the throat and breast.
“Wagtails go hopping along in a lively manner over the sand at the
water’s edge, looking for little worms. Every now and then they fly up
a few feet into the air, balance, pirouette, and alight again on some
slight elevation. They may also be seen skipping across the fields
among the sheep and standing on the backs of the latter even in the
shepherd’s presence, in order to get the parasitic insects lurking
under the wool. They live on small slugs, moths, flies, and larvæ.
“Midway between birds eating only seeds and those eating only insects
must be placed, in respect to their food, those that have a mixed diet
and eat, according to season, place, and circumstances, insects and
seeds, larvæ and berries. Their beak has neither a strong, conical
structure like that of purely granivorous birds, nor a delicately
slender form like the beak of the insect-eaters, but is between these
two extremes. This beak, instrument of general utility, is found in the
lark, that bringer of gladness to our plowed fields; in the thrush and
the blackbird, lovers of grapes and juniper-berries, but not less fond
of insects; in the oriole, that superb black and yellow bird so
appreciative of cherries flavored with toothsome larvæ; and in the
starling, devourer of figs, grapes, insects, slugs, and various kinds
of seeds.
“The starling is a magnificent bird almost as large as a blackbird,
brilliant with glints of metallic luster on a dark background. Its
color is black with greenish sheen on head and wings and violet on
breast and back. Most of the feathers are adorned with a reddish-white
spot at the very end. It nests under the roofs of buildings, in
dove-cotes, and in hollow tree trunks. The nest, composed on the
outside of straw, and within of dry grasses and feathers, contains four
spotless whitish eggs. Starlings come to us in the autumn. They fly in
large flocks, whirling about like grain winnowed in a sieve and sending
forth piercing cries from high up in the air. They alight in marshes
and damp meadows, where they destroy much vermin.”