Page 92 - The Miracle of Migration in Animals

THE MIRACLE OF MIGRATION IN ANIMALS

Homing pigeons, before leaving their territory,
have been observed circling above their home one
final time, probably to take another look at the re-

gion’s geographical features. In an experimental trial
the birds’ forward vision was restricted to one or two
meters (a few yards) by the application of opaque
contact lenses, yet they still managed to find their
way home. For a while, it was assumed that the birds
used the position of the Sun to find their way, but
when released on a completely overcast winter’s day,
they were still able to return home. However, when
magnets were attached to their heads powerful
enough to drown the world’s magnetic signals, they
lost their way. From this, it was deduced that the
birds were guided by the Earth’s magnetism, but it is
still not fully understood how birds can perceive it.
In recent years, very small particles of magnetic ma-
terial have been discovered in the pigeons’ skull and
neck muscles. 27
How birds find their way is a most remarkable

mystery, on which a great deal more research will be
conducted. Whatever the methods birds may use, its
miraculous aspect remains unchanged.
If a bird regulates the direction it goes in accord-
ing to changes in Earth’s magnetic field, some struc-
ture in its body must enable it to measure these
changes. This invites certain questions. If a bird does
not come into existence together with this system ap-
propriate to its needs, have such systems developed
by random mutations as the creatures evolve, as the

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