How do migratory songbirds cross the Sahara?

Many European songbirds winter in Africa south of the Sahara.Along their migratory routes they must fly over the huge desert belt of the Sahara twice a year. For decades ornithologists have assumed that most migrants cross this 'ecological barrier' in one long non-stop flight of thousands of kilometres. Results of recent research, however, suggest that many of the songbirds that migrate across the Sahara follow an intermittent migratory strategy with regular stopovers in the desert.