1. An Andean Condor That Flew for 5 Hours Without Flapping
The Andean condor is considered the heaviest bird that relies on soaring, a method of flying without flapping [1]. To put its weight in perspective, 15kg is roughly equivalent to three standard 5kg bags of rice. Researchers fitted tracking devices on eight growing condors and analyzed over 216 hours of flight data [2][3]. The results were striking: the birds spent only about 1% of the time they were flying flapping their wings [2][3]. One condor flew for 5 continuous hours, covering about 172km (107 miles), without flapping at all [2]. Across the 216 hours of flight data, about 1%—roughly 2 hours—was spent flapping. Flapping is the exception, not the rule.
2. Why Condors Flap Mostly During Takeoff
If flapping is so rare, when do the condors use it? The study reports that more than 75% of all flapping occurred during takeoff [4]. It seems that the initial push to lift a heavy body off the ground requires active wing movement. Once airborne, however, the condors spend long periods without flapping. This raises the question: what supports their bodies while they are not flapping? The answer lies in the next section: rising air currents.
3. Thermals: Rising Warm Air Currents That Lift Condors
The condors were riding on updrafts known as thermals. These are currents of air that become lighter than the surrounding air because they are warmed by sunlight hitting the ground [5]. This warm air rises. However, it does not rise in a smooth, continuous column. Instead, it rises in intermittent bubbles, much like the blobs in a lava lamp [1]. The position and timing of these rising bubbles are not fixed. Researchers compared this chaotic movement to the way bubbles move within a lava lamp to explain how the air behaves [1].
4. How Condors Circle in Thermals and Glide to the Next One
When a condor finds a thermal, it circles within it to climb higher. Once it reaches a sufficient altitude, it glides away, descending at an angle while moving forward to search for the next updraft [3]. This cycle of climbing and gliding is repeated. Gliding uses less energy than flapping, but the bird loses height as it moves forward. To compensate, birds that are good at gliding use thermals to gain height and gliding to gain distance [6]. This method of staying aloft by riding rising air is called soaring [6]. It is similar to taking an elevator up and then using a slide to move forward. However, unlike a slide, the bird can choose its direction in mid-air. Although it looks effortless, the condor makes fine adjustments to its balance by tilting its tail feathers left and right [6].
5. The Danger of Gliding Between Thermals
The most precarious part of this flying style is the transition between thermals. If the bird cannot find the next rising air current, it may descend unintentionally to the ground. The study observed that flapping increased when condors were switching between thermals or when they were close to the ground [2]. The reason for this increase is an interpretation by the researchers, not a confirmed fact [2]. For a bird as large as a condor, researchers state that relying on soaring for movement is theoretically the only option [1]. Therefore, the success of finding the next thermal is directly linked to whether the bird can continue flying. We should avoid stating the specific reason for the increased flapping as a definite fact.
6. How Experience and Wind Help Vultures Soar Better
Does skill in soaring improve with experience? A study on white-backed vultures, not condors, compared adult and juvenile birds [7]. In conditions where wind shear (the change in wind direction and strength at different heights) was moderate, specifically on the downwind side of thermals, adults climbed faster than juveniles [7]. The juveniles were less efficient and used more energy [7]. There was no difference in how they selected thermals, but the adults were better at climbing within those conditions [7]. This suggests that technique may improve with experience. Thermals are not the only source of lift. Research on black eagles in Africa shows they also use "orographic lift," which is rising wind created when wind hits a mountain slope or ridge [8]. However, these findings about black eagles cannot be automatically applied to all eagles or condors [8].
7. How You Can Observe Soaring Birds Yourself
In the sky near you, you may see large birds spreading their wings and circling. If you spot one, try counting how many times it flaps and watch which direction it goes afterward. Be careful not to look directly at the sun or step into the road while observing. For further reading in Japanese, the Hiratsuka City Museum's "Various Ways of Flying" is an accessible entry point [6]. The condor research can be read through the University of Swansea's announcement [1] and Tsukuba Science News [3].