Bats are often seen as insect eaters, but some species have a surprising diet that includes birds. Scientists recently discovered evidence of bird remains in bat droppings, showing these bats hunt more than just bugs. New research reveals how they manage to catch birds in the dark sky using tiny sensors and clever hunting tactics.

Uncovering the Mystery of Bat Bird Hunting

For years, scientists wondered how certain bats could take down larger, faster prey like birds. To find out, biologist Elena Tena and her team attached ultra-light sensors to the biggest European bat, the greater noctule. These sensors were tiny—only four grams—so they didn’t interfere with the bats’ flight. They recorded sound, altitude, and movement as the bats flew through the Spanish night.

Over two years, the researchers tracked 14 bats and collected detailed data. They discovered that instead of attacking birds at their roosts, the bats ambushed them high above the ground — sometimes reaching altitudes of 1.2 kilometers. The bats would then dive rapidly, using echolocation to lock onto their target. These aerial pursuits lasted from half a minute up to nearly three minutes, much longer than their usual insect hunts.

The Aerial Attacks and How Bats Catch Their Prey

Once a bat identified a bird—often a European robin—it launched a high-speed dive. During the attack, the bat emitted rapid bursts of echolocation sounds to track the bird’s movements. The pursuit was intense and precise, more like aerial dogfights than typical bat hunts. After catching a bird, the bats didn’t land. Instead, they continued flying and ate their prey mid-air.

Researchers found evidence that the bats bit off wings to reduce drag and weight while in flight. They chewed on the birds for about 23 minutes, all while still flying. Eating in mid-air likely helps conserve energy, as landing and climbing back up would be energy-consuming. This method of hunting and eating mirrors their insect-catching tactics—fast, efficient, and done in the air.

Implications and Open Questions

This discovery raises many new questions. How often do these bats catch birds successfully? The study observed only two confirmed attacks—one successful and one unsuccessful—so their success rate might be around 50%. But with limited data, scientists can’t say for sure how common these hunts are.

Another mystery involves how birds respond to these attacks. Since bats use ultrasonic sounds for echolocation, birds might detect danger through wing beats or other sounds. Understanding this predator-prey interaction could shed light on bird defenses and how bats hunt in the dark sky.

Understanding the hunting habits of the endangered greater noctule is important for conservation. Knowing where and how they hunt can help protect their habitats and support their survival. This research opens new doors to understanding the complex ways bats adapt their hunting strategies in the wild.

Inspired by

• https://arstechnica.com/science/2025/10/tracking-bats-as-they-hunt-birds-in-the-skies-above-europe/

Sources

• cambridge.org
• doi.org