Page 63 - The Miracle of Migration in Animals

Finding the Shortest
Migration Route

As well as a sense of direction, birds also possess
navigation ability. While "sense of direction" can be defined as
guessing in which direction home lies, navigation in seamanship
means accurately defining one’s position on a map, to bring a ship
from one place to another. As already pointed out, experiments have
proven birds’ excellent navigational ability. In one such experiment,

a manx shearwater (Puffinus puffinus) taken from its habitat on the
coast of Wales and released from Boston 5,000 kilometers (3,100
miles) across the ocean, returned home in 12 days. 18
Depending on circumstances, birds use various clues in naviga-
tion. Missing one of these clues, they orient themselves by another.
Birds can generally read landmarks such as coastlines, rivers and
mountains. In addition, experiments have produced ample evidence

of their making use of the Sun and stars. To illustrate how complex it
can be to conceptualize birds’ direction-finding skill, consider the
black-winged stilt.
With the arrival of spring in their winter habitat of West Africa,
these birds leave for Siberia. They fly non-stop along the East
Atlantic shore for a total distance of 4,300 kilometers (2,600 miles)
until they reach the Dutch Wadden Sea.

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