Crossing the world’s largest hot desert in one fell swoop.
Each year, billions of tiny songbirds fly across the Sahara desert to spend the winter in Africa. On such an arduous journey, it was assumed that the birds would need to stop and take breaks during the most scorching parts of the day.
Researchers from the Netherlands were surprised to find that a small songbird called the pied flycatcher flies day and night, non-stop until reaching the desert’s edge. Their study was published in last month’s issue of Biology Letters.
The researchers kept tabs on the flycatchers during their migration by fitting them with tiny data-loggers at their breeding grounds in the Netherlands. The loggers constantly recorded light and temperature over the entire course of the journey.
Data retrieved from the loggers after the migration was complete revealed that some of the birds were flying for 40 to 60 hours straight. Given the speed at which they soar, this was more than enough time to allow the birds to clear the desert.
Preparation appears to be key for the 12-gram flycatchers, who are known to fatten up considerably before the trip.
The researchers suggest that the non-stop flight over the Sahara during spring and autumn migrations may be preferable to intermittently stopping for breaks because it shortens the duration of journey, lowering the risk of birds running out of fuel or getting dehydrated along the way.
Given the benefits of non-stop migration, the researchers now wonder whether other birds might be using this same strategy to cross the Sahara. “The next challenge is to compare species' migration strategies, to unravel how variable these patterns are and their associated costs and benefits,” they wrote.