After 25 years of suspicion, researchers have confirmed that Europe's largest bat, the greater noctule, hunts and eats small songbirds mid-air more than a kilometer above ground. Using tiny biologgers, the team recorded dives, captures, and feeding sounds during nocturnal chases. The findings, published in Science, reveal the bat's daring predation strategies.
For nearly a quarter century, scientists suspected that the greater noctule (Nyctalus lasiopterus), Europe's largest bat, preyed on small birds during flight. The hypothesis originated from Spanish bat expert Carlos Ibáñez and colleagues at the Doñana Biological Station in Seville, who found bird feathers in bat droppings. Despite evidence from roost monitoring, radar, and GPS trackers, direct observation in the dark proved elusive.
An international team, including researchers from Aarhus University and the Leibniz Institute for Zoo and Wildlife Research, fitted bats with lightweight biologgers. These devices tracked altitude, acceleration, movement, and sounds, including echolocation calls. The data showed bats soaring high to ambush migrating songbirds, which travel at night to evade daytime predators but face threats from ultrasonic-hunting bats.
Biologger recordings captured two chases: one abandoned after 30 seconds, the other succeeding after 176 seconds. In the successful hunt, the bat captured a robin near the ground, eliciting 21 distress calls, followed by 23 minutes of chewing sounds as it fed while flying low. X-ray and DNA analysis of bird wings beneath hunting areas confirmed the process: the bat bites to kill, removes wings to reduce drag, and uses its hind-leg membrane as a pouch to consume the prey airborne.
"We know that songbirds perform wild evasive maneuvers such as loops and spirals to escape predators like hawks during the day -- and they seem to use the same tactics against bats at night. It's fascinating that bats are not only able to catch them, but also to kill and eat them while flying. A bird like that weighs about half as much as the bat itself -- it would be like me catching and eating a 35-kilo animal while jogging," said lead author Laura Stidsholt from Aarhus University's Department of Biology.
Co-author Elena Tena described the recording as thrilling yet sobering: "While it evokes empathy for the prey, it is part of nature. We knew we had documented something extraordinary."
The greater noctule is endangered due to forest habitat loss and poses no threat to songbird populations given its rarity. Understanding its ecology is essential for conservation strategies. The study was published in Science (2025; 390 (6769): 178, DOI: 10.1126/science.adr2475).