The secrets of the travels of migratory bats, revealed

While bird migration is well documented and studied, the same is not true for seasonal bat migration, especially for the few long-distance migratory species. Recent research reveals previously unknown details about how these animals make such trips.

These bats, nocturnal travelers, face significant challenges, such as high energy demands, anthropogenic threats, declining insect populations, and global climate change.

Recent evidence also shows changes and reductions in the ranges of migratory bats.

Bats’ migration decisions seem linked to local climate, especially favorable winds that facilitate both foraging and movement. However, due to technological limitations, the migratory patterns of these bats have not been fully tracked.

With the aim of helping to correct this situation, a team led by Edward Hurme, from the Max Planck Institute of Animal Behavior in Germany, developed a new biotelemetry technology that uses tags of the type known as the “Internet of Things.” (IoT), weighing 1.2 grams. These tags were used to track 71 female common noctule (Nyctalus noctule) during their annual spring migration through central Europe.

These IoT tags, connected to a 0G wireless network, collect location, activity and environmental temperature data, transmitting it daily without the need to recapture the bats.

Hurme and his collaborators discovered that the bats traveled up to 1,116 kilometers in 46 days, with flights that reached 383 kilometers in a single night, distances much greater than those recorded to date.

Common noctule bat. (Photo: Kamran Safi / Max Planck Institute of Animal Behavior)

It was also found that many bats preferred to synchronize the trip to their maternity roosts with warm nights and storm fronts, taking advantage of the tailwinds to reduce energy expenditure, which, colloquially, we could describe as “surfing the winds.”

However, the animals also showed surprising flexibility in determining migration times, demonstrating their ability to move under different conditions when necessary. However, females migrating towards the end of the season faced higher energetic costs due to the weight gain associated with mothering and less favorable wind and weather conditions.

The study is titled “Bats surf storm fronts during spring migration.” And it has been published in the academic journal Science. (Source: AAAS)