In 2011, Felix Lietchi and his colleagues at the Swiss Ornithological Institute attached electronic tags that log movement to six alpine swifts. The small birds—each weighs less than a quarter of a pound—spend the summer breeding in Europe, then migrate to Africa for the winter, thousands of miles away.
For more than 200 straight days straight, as revealed by his team’s study published today in Nature Communications, the birds stayed aloft over West Africa. The tags only collect data every four minutes, so it’s impossible to rule out the chance that they touched down occasionally in between these intervals—but every single one of the data points collected for more than six months in a row indicated that, at the time, they were either actively flying or at least gliding in the air.
It’s still a mystery how the birds are able to physiologically accomplish this feat. The diet aspect is relatively straightforward—they largely feed on airborne insects—but until now, opinions differed over the question of whether birds could sleep while aloft. Sleep patterns in birds are fundamentally different than in mammals, and the difficulty of studying the brainwaves of migrating birds makes it very hard to fully understand how they rest while in motion. But the fact that these swifts never touch down for such a long time indicates that they’re able to rest in midair.
This amazing report surprises me! I wonder how they can accomplish this? Lots more to learn!
thank you Ruth - I love reading about birds and their flight