Jeffrey Hamilton
By Stephen Beech
Bat Migration Revealed: Flying on Storm Fronts for Thousands of Miles
Imagine tiny winged creatures riding storm fronts as they journey thousands of miles across continents. This incredible behavior has been discovered by a team of researchers from the Max Planck Institute of Animal Behavior (MPI-AB) in Germany. Their findings unveil a fascinating aspect of bat migration, previously shrouded in mystery, and published in the journal Science.
How Bats Use Storms for Migration
The researchers studied 71 common noctule bats during their spring migration across Europe. Advanced sensors, weighing only 5% of the bats’ body mass, were attached to track their movements and environmental data. The study uncovered that bats utilize the warm air currents of storms to travel farther with less energy.
Dr. Edward Hurme, the study’s first author, emphasized the importance of sensor data, stating, “We don’t just see the path that bats took; we also see what they experienced in the environment as they migrated. This context provides insight into the crucial decisions they made during their journeys.”
Tracking Technology Breakthrough
The innovative tracking device, developed by engineers at MPI-AB and named ICARUS-TinyFoxBatt, revolutionizes the study of bat migration. By compressing 1,440 daily measurements into a 12-byte message, these tags transmit data via a network similar to a cell phone network. This allows researchers to monitor bats over vast distances.
Senior author Dr. Timm Wild explained, “The tags communicate with us from wherever the bats are because they have coverage across Europe much like a cell phone network.”
Bats’ Migration Patterns and Challenges
The study revealed that bats do not follow predefined migration corridors. Instead, they move over a broad landscape in a general northeastern direction, breaking the known record for the species by migrating almost 250 miles in a single night.
Dr. Dina Dechmann, a senior author of the study, highlighted the unique migration pattern, stating, “There is no migration corridor. We had assumed that bats were following a unified path, but we now see they are moving all over the landscape in a general north-east direction.”
Fueling Migration
Bats alternate between migratory flights and frequent stops to feed, continuous refueling being crucial for their survival. In contrast to migratory birds that gain weight before migrating, bats need to refuel nightly. This results in a “hopping pattern” rather than a straight journey.
Dr. Dechmann further elaborated, “Unlike migratory birds, bats don’t gain weight in preparation for migration. They need to refuel every night, so their migration has a hopping pattern rather than a straight shot.”
The Role of Storms in Migration
Researchers detected a significant pattern in the bats’ departure times, discovering that they left on nights with dropping air pressure and increasing temperatures. The conditions indicated the approach of storms, and the bats took advantage of the warm tailwinds to conserve energy.
Dr. Hurme noted, “They were riding storm fronts, using the support of warm tailwinds.” This observation confirms that bats, like birds, harness invisible atmospheric energy to power their continental flights.
Bat Migration Implications and Conservation
Understanding bat migration patterns and triggers can greatly impact conservation efforts. Migratory bats often collide with wind turbines, which pose a significant threat to their survival. Knowledge of migration timings and locations can help prevent such collisions.
Dr. Hurme suggested a proactive approach, “We can be stewards of bats, helping wind farms to turn off their turbines on nights when bats are streaming through.”
The Future of Bat Migration Research
The findings from this research open up new avenues for studying bat migration. Future studies could develop systems to forecast bat migration, enhancing conservation efforts and reducing human interference.
Dr. Hurme expressed optimism, saying, “More studies like this will pave the way for a system to forecast bat migration. This is just a small glimpse of what we will find if we all keep working to open that black box.”
