Night riders on the storm

BATS are chancers that ride the storm when migrating up to 1,000 miles - amazing scientists who expected them to follow a handful of flight paths.

- By Stephen Beech

Researchers attached sensors to common noctule bats leaving Switzerland on their annual spring journey to northern Europe. The tiny tags tracked their route but also recorded information like energy expended and air temperature.

Dr Edward Hurme revealed they saw a "striking" pattern: "On certain nights, we saw an explosion of departures that looked like bat fireworks.