Ten months in the air without touching the ground

Swifts (Apus apus), a small migratory bird of the family Apodidi, it seems shaped by air and air. In flight resembles a crescent moon, with a small head and tail which accompany the progress of the curvature of the wings. It was known for some time that this bird can fly for days without stopping, never settling anywhere, but now a research finds that it may even take 10 months in flight without alight.

He falls to the ground only when it has to build the nest, deposit and hatch eggs, because in flight can also mate.

A LITTLE REST FOR A MOMENT. Anders Hedenström, biologist at the University of Lund (Sweden), has conducted its study on Swift (see Current Biology, English) with the aid of detectors, in 1.1 grams, include accelerometer and light sensor, for determine the bird's location day and night.

In this way they were "followed" 19 swifts, between 2014 and 2015, who have spent the winter in West Africa and the summer in Europe.

Three of them have never laid on the floor, literally; others fell on rare occasions, during the night, and only for a few minutes. The fact is that on average the birds remained in flight for 99 percent of the time, with the exception of nesting period.

THE MYSTERY OF SLEEP. The recordings have allowed to verify that throughout the year, especially at dusk, the birds can soar up to over 2 km altitude. Hedenström believes that, when they arrive at these heights may rest until he fell asleep while continuing the flight as a glider. It is difficult to explain how the swifts and other birds, are able to sleep in flight: it should perhaps ricorrerere to brain sensors on their heads, but the ones available today weigh too much.