23
January 2003
Bird flight: U and non-U
U-shaped, that is, that birds use most power at low or high speeds and cruise at minimum power at intermediate speeds. That was called into question when the first such power curve was determined (for the magpie), as the curve was notably 'flat' over intermediate velocities. Technically demanding experiments have now been done for two more species, revealing a pronounced U-shaped power curve for cockatiels and an intermediate U-shape for doves. Clearly, power profiles depend on lifestyle and flight patterns. Meanwhile, the frigatebird shows how it can stay continuously aloft by virtue of efficient flight patterns and huge wingspan. These characteristics equip the birds well to exploit the sparse tropical waters in which they hunt.
Comparative power curves in bird flight
B. W. TOBALSKE, T. L. HEDRICK, K. P. DIAL & A. A. BIEWENER
Nature 421, 363–366 (2003); doi:10.1038/nature01284
| First Paragraph | Full Text (HTML / PDF) |
Flight performance: Frigatebirds ride high on thermals
HENRI WEIMERSKIRCH, OLIVIER CHASTEL, CHRISTOPHE BARBRAUD & OLIVIER TOSTAIN
This bird's bizarre physique and sparse hunting grounds account for its languid lifestyle.
Nature 421, 333–334 (2003); doi:10.1038/421333a
| First Paragraph | Full Text (HTML / PDF) |
