||In order to enable the bird to see so distant
an object, the eye has been exercising its telescopic powers, and yet,
in a second or two, when the Vulture is close to its prey, the whole form
of the eye must be changed, or the bird would mistake its distance and
dash itself to pieces on the ground.
By means of its powerful eyes the Vulture
can see to an enormous distance, and with great clearness, but neither
so far nor so clearly as is sometimes supposed. It is true that,
as soon as a carcase is discovered, it will be covered with Vultures, who
arrive from every side, looking at first like tiny specks in the air, scarcely
perceptible even to practised eyes, and all directing their flight to the
same point. 'Where the carcase is, there will the vultures be gathered
together.' But, although they all fly towards the same spot, it does not
follow that they have all seen the same object. The fact is they see and
understand each other's movements.
A single Vulture, for example, sees a dead
or dying sheep, and swoops down upon it. The other Vultures which are flying
about in search of food, and from which the animal in question may be concealed,
know perfectly well that a Vulture soars high in the air when searching
for food, and only darts to the earth when it has found a suitable prey.
They immediately follow its example, and in their turn are followed by
other Vultures, which can see their fellows from a distance, and know perfectly
well why they are all converging to one spot.