Could Evolution Do This?

Swiftlets are small birds that live in southwestern Asia and Australia.
They make their nests far back in dark caves. These birds have
small eyes and the caves are pitch black. With fast wings, such as swallows
have, the swiftlet flies at high speed into its cave. Rapidly it flies
directly to one tiny nest among hundreds. As soon as the bird enters the
cave, it begins making a series of high-pitched clicks. The little bird
has the ability to vary the frequency of the sounds and, as it approaches
the wall, it increases the number of clicks per second until they are
emitted at about 20 per second. The time required for the clicks to
bounce off the wall and return reveals the distance to the wall. Scientists
have tried to figure out why the clicks vary in frequency as the bird
gets closer to the wall. They eventually discovered that the tiny bird—
with a brain an eighth as large as your little finger—does this in order
to hear the return echo! The problem is that the click must be so short
and so exactly spaced apart, that its echo is heard by the ear of the
bird—before the next click is made. Otherwise the next click will drown
the sound of the returning echo. By the way, how did the swiftlet identify
its own nest by those clicks? There are hundreds of nests in the
cave. Scientists try to solve such problems, but they are unable to do
so. Somehow, evolutionary theory does not seem to be of any help.


- The Evolution Cruncher