Page 40 - The Miracle of Migration in Animals

THE MIRACLE OF MIGRATION IN ANIMALS

tion. And so there is only one true explanation: God has created this
characteristic in migrating creatures.
Animals in the wild are evidence of God’s power, and that He is
the Almighty, Who creates incomparably. Those who persist in ignor-
ing this evidence and who look for a creator other than God are
clearly misguided. In a verse of the Qur’an, God tells of such people:

Say: “He is the All-Merciful. We believe in Him and trust in
Him. You will soon know who is clearly misguided.”
(Qur’an, 67:29)

How Do Birds Decide to Migrate?

Several factors prompt birds’ migrations. When one or a few of
these prevail, the migration marathon begins. One of these factors is
the gradual shortening of the days, since change in the length of day-
light has an effect on birds’ hormonal system.
Experiments have shown that the lengthening of the day stimu-
lates animals in different ways. Light primarily affects the hypothala-
mus, the nerve center in the brain that controls hunger and satiety. At
the same time the neighboring areas of the brain are stimulated, trig-
gering secretion of prolactin in particular, and corticosterone and sex
hormones from the adrenal glands. These hormonal changes cause an
extreme increase in birds’ appetite, and they begin to feed intensively
to build up the fat deposits necessary for migration, eating 40% more
than at other times of the year. The fats they accumulate are stored as
large deposits under the skin, in flight muscles, and in the abdominal
cavity. When the birds are not migrating, their body weight consists
of 3 to 5% fat, but at the time of migration, the rate increases to 15% in
birds flying short to medium distances, and 30 to 50% in those flying
long distances. These fat deposits fuel the flying muscles and also en-
sure the least fatigue on long distance flights. 8

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