<< Andean condors, at 10kg or more, are among the world’s heaviest flying birds. Once birds get this big, the energetic costs of flapping are so high they instead rely on currents of rising air to travel long distances. >>
AA << results showed that on average, condors fly for three hours a day, but they flap for less than two minutes of this - just 1% of their flight time. One bird even flew for more than five hours without a single flap, covering 172km. Surprisingly, the amount they flapped hardly changed whether they were in the Andes or the steppe, or whether it was windy or not. >>
<< Nonetheless, even in weak thermal conditions, which may occur in winter, (their) results suggest condors may flap for only around two seconds per km. This remarkably low investment in flapping flight is on a par with albatrosses. In fact, albatrosses appear to flap more than condors – between (1% and 15% of their flight time outside take-off) >>
<< What is particularly striking about our findings is that all the birds we studied were immature. There was some suggestion that flight performance improved with age, but the demonstration that all birds flap so rarely shows that it is possible for even young condors to invest little energy in flying. >>
Emily Shepard. We tagged Andean condors to find out how huge birds fly without flapping. Jul 13, 2020.
H. J. Williams, E. L. C. Shepard, et al
Physical limits of flight performance in the heaviest soaring bird. PNAS. doi: 10.1073/ pnas.1907360117. Jul 13, 2020
