‘Magical’: 17m insects fly each year through narrow pass in Pyrenees, say scientists

Exeter University study has origins in 1950 discovery by ornithologists who chanced upon a spectacle'

It is a weird and wonderful sight: millions of migratory insects funnelling through a single narrow pass high in the Pyrenees, looking like a dark flying carpet and emitting a low, deep hum.

A team of scientists from a British university that has been studying the phenomenon for the last four years has now concluded that more than 17 million insects fly each year through the 30 metre-wide Puerto de Bujaruelo on the border of France and Spain.