Its bare head is capped with a helmet. Unlike the plumage of most birds
its feathers are loose and hair-like, whilst its wings are merely
represented by a few black quills. It is flightless and entirely
dependent on its short powerful legs to carry it out of danger.]
[Illustration: _Photo: Gambier Bolton._
THE KIWI, ANOTHER FLIGHTLESS BIRD, OF REMARKABLE APPEARANCE, HABITS, AND
STRUCTURE]
The herring-gull is by nature a fish-eater; but of recent years, in some
parts of Britain, it has been becoming in the summer months more and
more of a vegetarian, scooping out the turnips, devouring potatoes,
settling on the sheaves in the harvest field and gorging itself with
grain. Similar experiments, usually less striking, are known in many
birds; but the most signal illustration is that of the kea or Nestor
parrot of New Zealand, which has taken to lighting on the loins of the
sheep, tearing away the fleece, cutting at the skin, and gouging out
fat. Now the parrot belongs to a vegetarian or frugivorous stock, and
this change of diet in the relatively short time since sheep-ranches
were established in New Zealand is very striking. Here, since we know
the dates, we may speak of evolution going on under our eyes. It must be
remembered that variations in habit may give an animal a new
opportunity to test variations in structure which arise mysteriously
from within, as expressions of germinal changefulness rather than as
imprints from without. For of the transmissibility of the latter there
is little secure evidence.