Bats surf storm fronts during spring migration

Area of Science:

• Ornithology and Mammalogy
• Animal Ecology and Behavior

Background:

• Long-distance migration is well-documented in birds but poorly understood in bats.
• Bats exhibit diverse migratory strategies, with long-distance movements being particularly rare and understudied.

Purpose of the Study:

• To investigate the migratory behavior of female common noctule bats (Nyctalus noctula) using advanced tracking technology.
• To determine the distances, routes, and environmental factors influencing bat migration.

Main Methods:

• Utilized lightweight, 1.2-gram Internet of Things (IoT) tags with onboard processing to monitor bat location, temperature, and activity.
• Tracked 71 female common noctules over three spring migration seasons across central Europe, covering distances up to 1116 kilometers.

Main Results:

• Observed bats migrating tens to hundreds of kilometers nightly, often coinciding with favorable warm fronts that provided wind support.
• Documented significant migratory flexibility, with bats adapting to diverse environmental conditions.
• Identified increased activity per distance traveled in late-season migrants, suggesting a potential trade-off for flexible timing.

Conclusions:

• Common noctule bats undertake extensive spring migrations, challenging previous notions of limited bat migratory distances.
• Bat migration is influenced by weather patterns, particularly warm fronts, but bats demonstrate notable adaptability.
• Flexible migration timing may incur energetic costs for female bats.