Cerulean Warbler
One of the great evidences of design in the cosmos is the migratory
behavior of living things on the earth. There are countless examples,
but one of the most amazing are the songbirds that migrate across the
Gulf of Mexico to spend their summer in northern latitudes. The staging
grounds for these birds as they prepare to migrate north are the area
between Honduras and the Yucatan Peninsula of Mexico. The cerulean
warbler has come some 2,000 miles to this area from the Andean
foothills where it spent the winter. It breeds in Wisconsin or Ontario,
so by the time it gets to the edge of the Gulf of Mexico it has a
considerable distance yet to go.
The cerulean warbler is a tiny bird which normally
weighs about a
third of an ounce (nine grams). Before it makes the flight across the
Gulf it will add as much as four grams of fat. In the days before its
departure the warbler will act restless, flitting up into the sky just
after sunset, but then settling back to continue to eat. Finally a
night will come when there is a tail wind, and this bird along with
millions of other warblers, thrushes, vireos, flycatchers, orioles, and
tanagers will take off right after sundown and head across the Gulf of
Mexico. The bird will have difficulty climbing to a cruising altitude
of several thousand feet due to the extra weight, but as the hours pass
the weight burns off. The birds' wings beat at 20 times a second, but
its air speed is still only 20 mph. Without the tail wind it would be
impossible for the bird to make the crossing.
Southerly winds prevail in the Gulf at this time of year and the
birds make the trip in 15-24 hours. If a cold front comes in, the birds
will fly higher as the warm winds ride over the cold air mass. If that
does not work, the birds may have to force their way through the cold
air mass which can add 16 hours to their trip. Once the fat reserves
are gone, the bird's metabolism will start to pull energy from its
breast muscles. Very rarely does a healthy bird run out of what is
necessary to make the trip.
From a chance viewpoint, such a journey is difficult to understand.
It would seem that birds that migrate over land routes would be much
more likely to survive and would dominate the population. The design
features that are built into this beautiful little bird enable it to be
able to move quickly between distant habitats and populate ecosystems
in the north that would be greatly restricted in life forms without it.
Knowing where to go, when to overeat, how high to fly, what to do in
a cold head wind, and when to take off all are processes that are
critical to survival and yet cannot be reasoned out by such a small
creature. There is an intelligence which has designed this into the
birds, and that designer is the same God who tells us we can know that
He is "through the things He has made" (Romans 1:19-22).
--Reference: Nature Conservancy,
Spring 2004, Volume 54, Number 1, page 41.
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Does God Exist?, NovDec04.