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Descent of Man [ 1871]

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Author Topic: Descent of Man [ 1871]  (Read 6406 times)
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« Reply #135 on: February 09, 2009, 03:12:29 pm »

We have as yet spoken only of the voice, but the males of various
birds practise, during their courtship, what may be called
instrumental music. Peacocks and birds of paradise rattle their quills
together. Turkey-cocks scrape their wings against the ground, and some
kinds of grouse thus produce a buzzing sound. Another North American
grouse, the Tetrao umbellus, when with his tail erect, his ruffs
displayed, "he shows off his finery to the females, who lie hid in the
neighbourhood," drums by rapidly striking his wings together above his
back, according to Mr. R. Haymond, and not, as Audubon thought, by
striking them against his sides. The sound thus produced is compared
by some to distant thunder, and by others to the quick roll of a drum.
The female never drums, "but flies directly to the place where the
male is thus engaged." The male of the Kalij-pheasant, in the
Himalayas, often makes a singular drumming noise with his wings, not
unlike the sound produced by shaking a stiff piece of cloth." On the
west coast of Africa the little black-weavers (Ploceus?) congregate in
a small party on the bushes round a small open space, and sing and
glide through the air with quivering wings, "which make a rapid
whirring sound like a child's rattle." One bird after another thus
performs for hours together, but only during the courting-season. At
this season, and at no other time, the males of certain night-jars
(Caprimulgus) make a strange booming noise with their wings. The
various species of woodpeckers strike a sonorous branch with their
beaks, with so rapid a vibratory movement that "the head appears to be
in two places at once." The sound thus produced is audible at a
considerable distance but cannot be described; and I feel sure that
its source would never be conjectured by any one hearing it for the
first time. As this jarring sound is made chiefly during the
breeding-season, it has been considered as a love-song; but it is
perhaps more strictly a love-call. The female, when driven from her
nest, has been observed thus to call her mate, who answered in the
same manner and soon appeared. Lastly, the male hoopoe (Upupa epops)
combines vocal and instrumental music; for during the
breeding-season this bird, as Mr. Swinhoe observed, first draws in
air, and then taps the end of its beak perpendicularly down against
a stone or the trunk of a tree, "when the breath being forced down the
tubular bill produces the correct sound." If the beak is not thus
struck against some object, the sound is quite different. Air is at
the same time swallowed, and the oesophagus thus becomes much swollen;
and this probably acts as a resonator, not only with the hoopoe, but
with pigeons and other birds.*

  * For the foregoing facts see, on birds of paradise, Brehm,
Thierleben, B. iii., s. 325. On grouse, Richardson, Fauna Bor.
Americ.: Birds, pp. 343 and 359; Major W. Ross King, The Sportsman
in Canada, 1866, p. 156; Mr. Haymond, in Prof. Cox's Geol. Survey of
Indiana, p. 227; Audubon, American Ornitholog. Biograph., vol. i.,
p. 216. On the Kalij-pheasant, Jerdon, Birds of India, vol. iii., p.
533. On the weavers, Livingstone's Expedition to the Zambesi, 1865, p.
425. On woodpeckers, Macgillivray, Hist. of British Birds, vol.
iii., 1840, pp. 84, 88, 89, and 95. On the hoopoe, Mr. Swinhoe, in
Proc. Zoolog. Soc., June 23, 1863 and 1871, p. 348. On the
night-jar, Audubon, ibid., vol. ii., p. 255, and American
Naturalist, 1873, p. 672. The English night-jar likewise makes in
the spring a curious noise during its rapid flight.

  In the foregoing cases sounds are made by the aid of structures
already present and otherwise necessary; but in the following cases
certain feathers have been specially modified for the express
purpose of producing sounds. The drumming, bleating, neighing, or
thundering noise (as expressed by different observers) made by the
common snipe (Scolopax gallinago) must have surprised every one who
has ever heard it. This bird, during the pairing-season, flies to
"perhaps a thousand feet in height," and after zig-zagging about for a
time descends to the earth in a curved line, with outspread tail and
quivering pinions, and surprising velocity. The sound is emitted
only during this rapid descent. No one was able to explain the cause
until M. Meves observed that on each side of the tail the outer
feathers are peculiarly formed (see fig. 41), having a stiff
sabre-shaped shaft with the oblique barbs of unusual length, the outer
webs being strongly bound together. He found that by blowing on
these feathers, or by fastening them to a long thin stick and waving
them rapidly through the air, he could reproduce the drumming noise
made by the living bird. Both sexes are furnished with these feathers,
but they are generally larger in the male than in the female, and emit
a deeper note. In some species, as in S. frenata (see fig. 42), four
feathers, and in S. javensis (see fig. 43), no less than eight on each
side of the tail are greatly modified. Different tones are emitted
by the feathers of the different species when waved through the air;
and the Scolopax wilsonii of the United States makes a switching noise
whilst descending rapidly to the earth.*

  * See M. Meves' interesting paper in Proc. Zool. Soc., 1858, p. 199.
For the habits of the snipe, Macgillivray, History of British Birds,
vol. iv., p. 371. For the American snipe, Capt. Blakiston, Ibis,
vol. v., 1863, p. 131.

  In the male of the Chamaepetes unicolor (a large gallinaceous bird
of America), the first primary wing-feather is arched towards the
tip and is much more attenuated than in the female. In an allied bird,
the Penelope nigra, Mr. Salvin observed a male, which, whilst it
flew downwards "with outstretched wings, gave forth a kind of crashing
rushing noise," like the falling of a tree.* The male alone of one
of the Indian bustards (Sypheotides auritus) has its primary
wing-feathers greatly acuminated; and the male of an allied species is
known to make a humming noise whilst courting the female.*(2) In a
widely different group of birds, namely humming-birds, the males alone
of certain kinds have either the shafts of their primary wing-feathers
broadly dilated, or the webs abruptly excised towards the extremity.
The male, for instance, of Selasphorus platycercus, when adult, has
the first primary wing-feather (see fig. 44), thus excised. Whilst
flying from flower to flower he makes "a shrill, almost whistling
noise";*(3) but it did not appear to Mr. Salvin that the noise was
intentionally made.

  * Mr. Salvin, in Proceedings, Zoological Society, 1867, p. 160. I am
much indebted to this distinguished ornithologist for sketches of
the feathers of the Chamaepetes, and for other information.
  *(2) Jerdon, Birds of India, vol. iii., pp. 618, 621.
  *(3) Gould, Introduction to the Trochilidae, 1861, p. 49. Salvin,
Proceedings, Zoological Society, 1867, p. 160.

  Lastly, in several species of a sub-genus of Pipra or manakin, or
manakin, the males, as described by Mr. Sclater, have their
secondary wing-feathers modified in a still more remarkable manner. In
the brilliantly-coloured P. deliciosa the first three secondaries
are thick-stemmed and curved towards the body; in the fourth and fifth
(see fig. 45, a) the change is greater; and in the sixth and seventh
(b, c) the shaft "is thickened to an extraordinary degree, forming a
solid **** lump." The barbs also are greatly changed in shape, in
comparison with the corresponding feathers (d, e, f) in the female.
Even the bones of the wing, which support these singular feathers in
the male, are said by Mr. Fraser to be much thickened. These little
birds make an extraordinary noise, the first "sharp note being not
unlike the crack of a whip."*
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