Can you do anything for 10 months straight without stopping? Dance, ride a bike, drive a car, stand in one place? No? Didn't think so. Humans aren't set up for that sort of thing. We lack that kind of monumental endurance.
But that's not true for some animals. Biologists just discovered that a little bird called the common swift (Apus apus) can fly for 10 months straight without landing. Using a new type of data logger that detects both light and the movement of the birds, researchers at Lund University in Sweden discovered that while some individuals might land occasionally for brief periods, most remain airborne for their entire 10-month migration period, landing only for their two-month breeding season. The study was published in the journal Current Biology.
"This discovery significantly pushes the boundaries for what we know about animal physiology. A ten-month flight phase is the longest we know of any bird species – it's a record", says Dr. Anders Hedenström, a Lund University biologist, in a press release.
Many birds can fly long distances. The wandering albatross, for instance, can travel 10,000 miles (16,090 kilometers) without flapping its wings even once. And earlier this year researchers determined that hummingbirds can fly 29 million times the length of their own body without stopping.
What's mystifying about the common swift, though, is that its flight requires almost constant wing-flapping, making its grueling migratory habits even more of a physiological mystery than that of a soaring bird like the albatross, which is basically a big hang glider. When do the swifts sleep? Do they sleep? How could they possibly eat enough to stay so active for so long? What is their deal?!
The researchers don't have answers to any of these questions yet. They found that the birds that never landed a single time in the 10-month period had molted all of their flight feathers and had grown new ones, whereas the birds that landed occasionally didn't molt their wing feathers. Still, there is a small, seemingly insignificant difference in flight time between those that rested and those that didn't – of the 13 birds wearing data loggers, even the individuals that occasionally took a load off stayed on the wing 99.5 percent of the time during the 10-month period.
"Whether they moult or not could indicate small differences in their general condition or burden of parasites," says Hedenström, "and explain the flight behaviour of individual birds within the species."
So the next time you have a hard time getting off to the gym, just be grateful you're not a common swift, exercising endlessly for nearly an entire year.