Migrating birds face many risks

October 17, 2004|By Alan Tennant

IN FOLLOWING peregrine falcons, the most affecting thing I found was the magnitude of their transcontinental journeys. During the course of these global pilgrimages, tundra-living Arctic falcons -- like the countless smaller migrants streaming northward on spring migration below our little Cessna -- awed my pilot and me with what I can only call their grandeur of purpose.

It was a determination to reach some far shore that is also expressed in the epic journeys of a few mammals, reptiles and fish. Yet nothing equals the existential courage of birds.

That valor is what makes the preservation of these small travelers' nesting grounds so important. Already, returning songbirds, winging in to our eastern woodlands from ever more deforested winter ranges in the tropics, find their natal trees bulldozed into shopping malls and parking lots.

Shorebirds that, after long flights up from South America, drop onto coastal beaches and mud flats see only oceanfront condominiums. And prairie-living species look down, on their arrival every spring, at alien blankets of just-framed residential rooftops spread across their ancestral grasslands.

Longer distance travelers -- those making even more heroic pilgrimages to breeding in the Arctic, now find their chill northern Eden on the brink of similar destruction. Like their relatives to the south, the doughty heroes of 10 million annual flights to the tundra may soon find that fragile ecosystem irreparably changed -- sacrificed to satisfy, at most, a few months' worth of our prodigious appetite for oil.

As veteran aviator George P. Vose and I followed our falcon -- one we named Amelia after long-distance pioneer Amelia Earhart -- during her long flight north, it gradually became clear that every pair of wings aloft around us carried a small, determined soul that, with every dawn once more flung itself into the air, filled with the incandescent expectation of seeing its place of birth.

That is what moved me most about our companion travelers: their devotion. Devotion to place; sometimes to mates. The single-ounce specks of life that are white-crowned sparrows, when trapped and carried by researchers to the far side of the continent, nevertheless somehow find their way back, faithfully returning to the same brushy fields where they first saw the light beyond their hatching shells.

Many migrants, of course, fail to make it. Often, their lives are lost on ocean passages. Sadder by far are the deaths of the warblers, vireos and thrushes that, after a long night and most of the following day in flight over the Gulf of Mexico, struggle ashore three feet off the last waves, only to be smashed on the grills of vacationer traffic streaming along Texas' coastal highways.

A few migrants have always fallen to the birds of prey that shadow their flocks like wolves trotting beside nomadic bison herds. But such hunters never bring the arrogant, indifferent death dealt by mankind's new technology. Instead, by filling their captors' crops with food, the bodies of fallen songbirds still go on, fueling the river of migration of which they remain a part.

But what of the tundra falcons? True Zhivagos in their commitment to mates and home, breeding pairs may spend three quarters of every year apart, completing their mysterious autumn journeys to the tropics entirely alone. Yet, as spring moves north across the hemisphere, they somehow know to once more dig the samurai blades of their slender wings into the currents of air and, from half the globe away, loft themselves onto the long highway toward the lands below the northern pole. The strongest arrive from the Caribbean or South America, then perhaps -- like our Amelia -- follow the Rockies' Front Range on to the Yukon or Alaska.

There, they will rendezvous with the same long-remembered partner they saw last under the falling sun of the previous September. In the sky over their always sunlit summer bluffs they'll once more court, spinning wing-borne Ferris wheels in the air above familial aeries that may house lineages of peregrines stretching back to the Pleistocene.

No Spring Break traffic will smack them here, but in their blood and tissue some of these Arctic wanderers carry traces of the agricultural chemicals -- including the DDT still used by village exterminators from the Yucatan to Venezuela. Other falcons bear petroleum residue first ingested by their shorebird prey. Easy kills when sickened by feeding on organochlorine-saturated invertebrates picked from the banks of the open sludge ponds of the Latin American petrochemical industry. Wading birds metabolically concentrate the signature toxins that last in the bodies of their predators, weeks and thousands of miles later in the far reaches of the Arctic.

Now, however, this remote northern Eden faces a more direct threat from the intrusion of man. Because oil exploration on the Arctic Slope takes place far from public view, its impact is almost as invisible, making the drilling easy to rationalize, and partly because of that increased petrochemical activity here remains one of this administration's primary energy objectives.

It is not worth it. Expanded Arctic Slope petroleum development would cost the earth one of the few remaining stages large enough to display not only the drama but the essential optimism of life itself. For with the sacrifice of this last Arctic Serengeti would go the chance -- ours and that of everyone else on earth -- to participate in the spectacle of the small, courageous lives that every spring struggle back with so much heart, and from so far away, to reach it.

Alan Tennant is the author of On the Wing: To the Edge of the Earth with the Peregrine Falcon.

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