00 |1000 : 109 |
|Call (from Mr. Fox) | 717 | 92 |1000 : 129 |
+--------------------+-------------------+-----------------+-----------+

Lastly, I weighed the furcula, coracoids, and scapula of a wild duck
and of a common domestic duck, and I found that their weight,
relatively to that of the whole skeleton, was as one hundred in the
former to eighty-nine in the latter; this shows that these bones in the
domestic duck have been reduced eleven per cent. of their due
proportional weight. The prominence of the crest of the sternum,
relatively to its length, is also much reduced in all the domestic
breeds. These changes have evidently been caused by the lessened use of
the wings.

It is well known that several birds, belonging to different Orders, and
inhabiting oceanic islands, have their wings greatly reduced in size and
are incapable of flight. I suggested in my 'Origin of Species' that, as
these birds are not persecuted by any enemies, the reduction of their wings
has probably been caused by gradual disuse. Hence, during the earlier
stages of the {287} process of reduction, such birds might be expected to
resemble in the state of their organs of flight our domesticated ducks.
This is the case with the water-hen (_Gallinula nesiotis_) of Tristan
d'Acunha, which "can flutter a little, but obviously uses its legs, and not
its wings, as a mode of escape." Now Mr. Sclater[454] finds in this bird
that the wings, sternum, and coracoids, are all reduced in length, and the
crest of the sternum in depth, in comparison with the same bones in the
European water-hen (_G. chloropus_). On the other hand, the thigh-bones and
pelvis are increased in length, the former by four lines, relatively to the
same bones in the common water-hen. Hence in the skeleton of this natural
species nearly the same changes have occurred, only carried a little
further, as with our domestic ducks, and in this latter case I presume no
one will dispute that they have resulted from the lessened use of the wings
and the increased use of the legs.

THE GOOSE.

This bird deserves some notice, as hardly any other anciently domesticated
bird or quadruped has varied so little. That geese were anciently
domesticated we know from certain verses in Homer; and from these birds
having been kept (388 B.C.) in the Capitol at Rome as sacred to Juno, which
sacredness implies great antiquity[455]. Th