Greater noctule bats prey on and consume passerines in flight.

Despite billions of passerines seasonally migrating during the night at high altitudes, only three bat species have been found to consistently tap into this rich prey resource. However, it remains unknown where and how these bats locate, catch, and ingest relatively large passerine prey. Here, we used high-resolution biologging tags to reveal that greater noctule bats (Nyctalus lasiopterus) ascend to high altitudes, engage in long echo-guided chases, and consume migrating passerines in flight. By using a private sensory channel through ultrasonic echolocation, prolonged chasing, and mid-air prey consumption, these predators can hunt nocturnally migrating passerines at high altitudes and therefore exploit a rich food resource that remains largely inaccessible to most predators. Editor's summary: Bats have evolved to be efficient aerial predators for a wide array of prey. Although most people think of them as insectivores, there are bats that eat mammals and amphibians and even birds. Three bat species have been recorded preying on birds, but how and when they do this has been mostly unknown. Stidsholt et al. monitored greater noctule bats in flight and found that individuals track migrating birds using echolocation and consume them on the wing. These observations suggest that these efficient aerial predators have also evolved to prey on migrating birds. —Sacha Vignieri [ABSTRACT FROM AUTHOR]