Sunday, May 22, 2011

A river of birds

I keep an old National Geographic map posted on my wall. It is a map of the Americas with the flyways of migratory birds, long undulating arrows, some stretching from Canada and Alaska all the way to the southern tip of South America.

I was stunned the first time I saw that map and became instantly a bird watcher. I wanted to know more about this amazing phenomenon. Every autumn, these tiny feathered creatures develop the urge to move south. Some are veterans that have done the journey several times before; others are novices, with no knowledge of where they are going.

They know nothing beyond the nest where they were born just a couple of months before and the piece of land surrounding that nest. Now they are taken by this uncontrollable need to move. Are they following their parents or some ancestral instinct imprinted in their genetic material? In either case, they are inexorably pushed forward grueling hour after grueling hour, day after day. Most fly by night and choose higher altitudes to avoid being cooked alive by the heat of exertion and, perhaps, to escape predators.

So, they fly over meadows and forests, valleys and mountains and, most remarkably, over open ocean. An early Spanish explorer sailing through the Caribbean described a river of birds passing overhead.

Many know that they have arrived when they see the verdant forests of the Amazon and settle there for a few months, until the urge to move again brings them back to northern latitudes. Others keep going, on and on, five thousand miles and more, all the way to the Argentinean Pampas and to Patagonia. Only then they rest.

The roster of these long distance travelers is impressive. Starting with the most famous one, the peregrine falcon, the list goes on to smaller fliers: plovers, sandpipers, gulls, swallows, even a nighthawk and the tiny red eyed vireo. They all leave Canada and the United States in the late summer or fall, cross the equator and reach the Pampas at the start of the southern summer. There, they rest and wait until it is time again to start moving north in their quest to raise a family.

What captured my imagination the first time I saw that National Geographic map was the realization that the same bird I saw here in Pennsylvania in the summer may be arriving a couple of months later at my home town in Cordoba, Argentina. I told my family: If you see a bobolink, a swallow or a sandpiper, say hello to them. They are carrying my greetings from here.

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