In the second table we have eight birds, with their beaks much
longer than in the rock-pigeon, both actually and proportionally
with the size of body, and their feet are in an equally marked
manner longer, namely, in proportion, on an average by ·29 of an
inch. I should here state that in Table I there are a few partial
exceptions to the beak being proportionally shorter than in the
rock-pigeon: thus the beak of the English Frill-back is just
perceptibly longer, and that of the Bussorah Carrier of the same
length or slightly longer, than in the rock-pigeon. The beaks of
Spots, Swallows, and Laughers are only a very little shorter, or of
the same proportional length, but slenderer. Nevertheless, these
two tables, taken conjointly, indicate pretty plainly some kind of
correlation between the length of the beak and the size of the
feet. Breeders of cattle and horses believe that there is an
analogous connection between the length of the limbs and head; they
assert that a race-horse with the head of a dray-horse, or a
grey-hound with the head of a bulldog, would be a monstrous
production. As fancy pigeons are generally kept in small aviaries,
and are abundantly supplied with food, they must walk about much
less than the wild rock-pigeon; and it may be admitted as highly
probable that the reduction in the size of the feet in the
twenty-two birds in the first table has been caused by disuse,[38]
and that this reduction has acted by correlation on the beaks of
the great majority of the birds in Table I. When, on the other
hand, the beak has been much elongated by the continued selection
of successive slight increments of length, the feet by correlation
have likewise become much elongated in comparison with those of the
wild rock-pigeon, notwithstanding their lessened use.
As I had taken measures from the end of the middle toe to the heel of
the tarsus in the rock-pigeon and in the above thirty-six birds, I have
made calculations analogous with those above given, and the result is
the same— namely, that in the short-beaked breeds, with equally few
exceptions as in the former case, the middle toe conjointly with the
tarsus has decreased in length; whereas in the long-beaked breeds it
has increased in length, though not quite so uniformly as in the former
case, for the leg, in some varieties of the Runt varies much in length.
Public-domain text, read in full here on John Shaqi.
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