The Journey South

Script by Francie Von Mertens

Most bird species are migratory, and fall migration is well underway. The wave of birds and birdsong that surges northward in spring is now receding. This seasonal journey is so physically demanding and filled with perils that a logical question arises: why migrate? In spring, why head north in the first place?

If you picture North America, birds head north to an ever-broadening land mass. There's more room to set up nesting territories. More land also means more food and less competition for that food. Summer's longer days provide more daylight hours for foraging as adults feed the annual population explosion of hungry, begging nestlings. The farther north a bird migrates, the longer the days. Birds that stay put in Central or South America often produce fewer, smaller broods than migrants that head to the expansive north.

In late summer, migrants grow restless, feeding more and sleeping less as they fuel up for the trip south. Migratory restlessness grows until, one day, departure is the only choice. Birds leave the shelter of a familiar home territory for unknown perils that include fall storms, collision with skyscrapers and greater exposure to predators.

Each May, we welcome the return of birds and birdsong, Baltimore orioles, for example. Apple trees are in full, glorious bloom when oriole song fills the air. In fall, departures are less noticeable as they lack the courtship songs of spring. One day we realize the backyard oriole, or gray catbird is gone. But our loss is another's gain. I imagine a coffee farming family in Columbia, perhaps, welcoming orioles back in October. Whether north or south, we welcome back the survivors of an impressive and perilous journey.

(Script by Francie Von Mertens)