WASHINGTON - Weighing in at 150 pounds or more, the all-time biggest bird couldn't just hop into the air and fly away, researchers say. A team led by Sankar Chatterjee of Texas Tech University used computer programs originally designed for aircraft to analyze the probable flight characteristics of Argentavis magnificens, a giant bird that lived in South America 6 million years ago. Like today's condors and other large birds, Argentavis would have had to rely on updrafts to remain in the air. Doing so, it could have soared for long distances, they conclude in a paper in Tuesday's edition of...