Science & Inventions
Why a condor needs only a fifth of a swan's energy
A study published in Science on October 15, 2026, shows how rising air makes flying much cheaper for big soaring birds.
An Andean condor and a trumpeter swan are two of the heaviest flying birds, and both weigh about 11 kilograms. Yet the condor uses only about a fifth of the swan's energy to fly each kilometer. According to a study published in the journal Science on October 15, 2026, the difference comes from the air.
The condor rides currents of rising air, so it flaps its wings for only 0.1 percent of its flight time. The swan, on the other hand, flaps for about 99 percent of the time. Emily Shepard of Swansea University, one of the study's leaders, compares this to riding an elevator to the top floor. She calls natural flows of air “free fuel from the sky.”
Word in this story
To fly high in the air with the wings held out and almost still, often using rising air.
Sensors called accelerometers showed whether an animal was flapping or soaring.