July 2, 2007 — The old line, "It's a bird! It's a plane!" could once have applied to the world's largest known bird, Argentavis magnificens, which, with a 23-foot wingspan, was about the same size as a Cessna 152 light aircraft.
A study published in today's Proceedings of the National Academies of Science found that the bird was probably too big to accommodate both wing-flapping in flight and standing takeoff by its own muscle power.
The 159-pound bird, which lived in Argentina six million years ago during the Miocene period, had its own way to taxi down a runway.
"A short run, about 30 feet on a moderate slope, would give enough power — 600 watts — to become airborne," lead author Sankar Chatterjee told Discovery News.
Argentavis then had two lazy means for staying in the air. The first involved soaring over updrafts produced in the Andes foothills, explained Chatterjee, a professor of geosciences and curator of paleontology at the Museum of Texas Tech University.
In the pampas, or plains, where such updrafts are uncommon, the bird could switch to hitching a ride on thermals — columns of air that rise due to natural, sun-fueled heating.
"Once it entered in a thermal, which should have been plenty in the pampas, like modern eagles and vultures, it would circle and climb vertically within the rising column," Chatterjee explained.
