Latest research has shown the common swift is capable of remaining airborne for as long as ten months at a time. This study is the first to demonstrate flights of this length which used continuous monitoring and specially designed micro data loggers to track the birds.

Yet why would a swift want to fly for ten months, and how could they possibly manage it?

Lead researcher Professor Hedenström explains: “Swifts are extremely well adapted to a life in air, where they capture their food (insects). By being so extremely adapted to an aerial life, they become bad at moving on the ground, having very short legs only useful to perch on trees/walls.”

In fact, the graceful aerial acrobatics of the swift contrast horribly with their slow and clumsy movements on land. Staying in the air allows swifts to gather not just food but also nesting materials. They are also able to avoid any land based predators and long periods of flight are thought to reduce their risk of parasitic infection.

The marathon flight studied by the team from Lund University takes the birds from their breeding grounds in Sweden to the warmer climates of the Central African rainforests where they spend the winter, and back again in time for the next breeding season. Some of the monitored birds were found to roost briefly but those with the longest recorded flights did not land once during the whole trip there and back!

The team made this record-breaking discovery using advanced new technology designed specifically for this experiment.  Professor Hedenström describes the problems the team had when planning the experiment and how the issues were overcome with the help of expert engineers.

“We required new technology, which was developed in-house by engineers that work in our group, in close collaboration with scientists. It builds on state-of-the-art micro data loggers and sensors that measure acceleration which, in combination with clever sampling routines, allowed us to monitor flight activity during a year for 13 birds, 5 of them during 2 years.”

It is hoped further work may also be able to study the sleeping habits of the swifts as they undertake these prolonged journeys. One proposed theory suggests these small but mighty athletes could actually be napping mid-flight by drifting on warm air currents to conserve their energy.

With such exciting new equipment at their disposal, these researchers are eager to discover more about the migratory patterns of swifts and of many other bird species as well.

Hedenström, A., Norevik, G., Warfvinge, K., Andersson, A., Bäckman, J., & Åkesson, S. (2016). Annual 10-Month Aerial Life Phase in the Common Swift Apus apus. Current Biology.
Discover the story behind the research through the scientist’s eyes, subscribe to Biosphere digital magazine for access to in-depth articles that bring the natural world to life.