The Andean Condor is a giant vulture that lives along South America’s west coast. It’s one of the heaviest flying birds in the world, weighing more than 30 pounds. Yet it can stay aloft for hours at a time.

How do condors do it? Efficiency!

The condor launches itself from a high peak or cliff, spreads its massive wings—the largest in surface area of any living bird—and soars.

It will then ride thermals, currents of hot air rising from the ground, scanning the land below for carrion to scavenge.

If the condor doesn’t find a meal, it soars on, transitioning from one thermal to the next. 

Scientists recently tracked one bird and found it could fly this way for five hours, covering more than a hundred miles, without flapping even once!

In fact, condors have been shown to flap their wings only one percent of their total flight time, with 75 percent of their energy expended just getting airborne.

Because takeoff is so energy intensive, the big birds must avoid unnecessary landings. Meaning they have to manage their flight path very carefully.

How can they navigate from one invisible rising air current to another? Perhaps they watch the behavior of other birds or have learned to read the landscape to look for terrain that could produce updrafts.

Scientists still don’t know; a mystery that perhaps one day we’ll be able to reveal on EarthDate.