The Swainson's hawk has been migrating between the Western United States and Canada and its winter home in the Pampas since long before hemispheric trade and globalized agriculture became hot topics.
But now that Pampas farmers are looking to produce for a world market - and turning to a cupboard full of pesticides to do it - the hawk with the world's longest-recorded migratory path is in serious decline.
All around the province of La Pampa, where the hawks gather to sit out the North American winter, posters with a drawing of the familiar, regal bird ask local farmers: "Help your ally - Don't use monocrotophos."
Monocrotophos is a chemical compound used mainly to kill grasshoppers. It was withdrawn from the US market in 1988 for its adverse effect on wildlife - but that didn't stop foreign production, or impede the shipment of US stocks of the chemical to other countries, including Argentina.
The cause of the hawk's decline was understood only recently. But then, the decline was noticed only relatively recently. And what researchers from the US, Canada, and Argentina found is that the decline coincided with changes in Argentine agriculture, primarily in La Pampa.
When the Pampas region was dedicated mostly to cattle, alfalfa, and wheat, there was little use of damaging pesticides. But with a partial shift over the last decade to new and internationally sought crops like sunflowers and soy beans - crops that are susceptible to annual grasshopper plagues - new pesticides like monocrotophos became popular.
"This is a typical globalization problem," says Ricardo Thornton, public information director at the Santa Rosa office of the National Agricultural Technology Institute. What everyone has to realize, he says, is that pesticide use can no longer be looked at simply on a country-by-country basis.
The problem is that Swainson's hawks feed on grasshoppers and small rodents. In fact, their name in Argentina is aguilucho langostero, or locust-eating hawk. So farmers looking to control grasshoppers with new pesticides were in fact doing in one of their chief allies.
Recent studies suggest that 5 to 10 percent of the hawks were dying annually over recent years, with some experts claiming the population has declined by a whopping 90 percent. In response, several US and Canadian agencies, together with INTA and other Argentine agencies, have mounted an international project to intensify hawk monitoring and to educate farmers about the bird's plight.
As a result, the Swainson's hawk appears to be somewhat safer. "Use [of monocrotophos] is already much less than before, but we'll still have to put [Swainson's hawk] on our endangered list" if annual kills don't decline still further, says Santiago Krapovickas, conservation director at the Ornithological Association of La Plata in Buenos Aires.
The key will be education, Mr. Thornton says. "This is long process, and it involves not just this pesticide and this species, but demonstrating to the farmers they can do just as well without endangering the whole natural system," he says.
Thirty percent of Argentina's threatened bird species live in grasslands, according to the Ornithological Association of the Plata. Their biggest threat is loss of habitat. The Eskimo curlew already may be extinct, and the austral rail is critical. Other species in danger: cock-tailed tyrant, ruddy headed goose, and ochre-breasted pipit.