Dear A. M. Costa Rica
The article [Friday] hit on different topics about migratory birds visiting here and further south for the winter in North America.
There is an added discussion on this migration by many ornithologists. Are they really migrating from the North America or are they migrating to North America? If we look at the total time spent in one area, the migratory birds actually spend much less time in North America and more time in Central and South America. They actually only go north to raise a family and as soon as the family is ready to head south they do just that.
So the question, one may ask is, why would they fly all the way to the U.S. just to have their babies instead of just having their young down here. There are several good reasons to go north.
First there are many less predators to deal with when raising their young in a nest in North America.
Secondly, the birds arrive in Spring. Spring time is a time when insect populations explode. Thus there is an abundance of food to feed baby birds.
A third point is the days are longer in the north and there is more time to spend feeding those babies. So as soon as these babies are able to fly a long distance the family is ready for their journey south to live most of their life, only returning to North America to have another family.
Henry Kantrowitz
Punta Leona
EDITOR'S NOTE: Mr. Kantrowitz is a recognized expert on birds.
