Study Finds Common Swift Can Fly Nearly Ten Consecutive Months Without Landing

Posted on October 28, 2016

Common Swift in flight

A new study conducted by researchers from Lund University in Sweden has found that the common swift can fly for nearly ten straight months without ever landing. The researchers used a new type of microdata log to study the birds long duration flights.

Professor Anders Hedenström at the Department of Biology in Lund, says in a statement, "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."

The researchers followed 13 individual birds for as long as two years. A lightweight microdata log was attached to each bird that enabled researchers to determine whether the birds were in the air or not. It also provided data about their acceleration and where they had been at any given time. Data from some of the birds indicates that they did not land a single time in ten months. The other birds landed during short periods at night, sometimes during an entire night. However, even these birds spent more than 99.5% of their ten-month migration and hibernation period in the air.

The birds that never landed were all found to have moulted and gained new flight feathers, while the majority of those who, on some occasion, landed had not moulted their wing feathers. Results of the study were published in Current Biology.

Hedenström also says, "Whether they moult or not could indicate small differences in their general condition or burden of parasites, and explain the flight behaviour of individual birds within the species. They might do as the frigate bird and sleep while gliding. Every day, at dusk and dawn, the common swift rises up to an altitude of about two–three kilometres. Perhaps they sleep during a declining glide, but we're not sure."



Photo: N. Camilleri