Introduction: A surprising apex of the nocturnal skies
While bats are widely celebrated for eating insects, a striking exception exists high above Europe’s forests. The greater noctule bat (Nyctalus lasiopterus), Europe’s largest bat, hunts nocturnally migrating birds in flight. A recent study employing high-resolution biologging tags confirms that these bats climb above 400 meters to intercept and capture birds mid-air, then sustain an extended meal during descent. This discovery reshapes our understanding of nocturnal food chains and highlights how a single predator can exploit a resource traditionally considered inaccessible.
Methods: following a flight path with high-tech trackers
Researchers led by Laura Stidsholt equipped 14 greater noctules with advanced biologging devices capable of recording altitude, echolocation signals, and 3D movement. The devices allowed the team to correlate hunting bursts with precise aerial maneuvers and to identify when a bat targeted a bird rather than its typical insect prey. By combining acoustic data with video- or audio-confirmed prey calls, the scientists could verify successful captures and subsequent consumption. This approach addresses long-standing questions about where, when, and how these formidable aerial pursuits occur, moving beyond indirect evidence from wing fragments or fecal pellets.
Two dramatic hunts: high-altitude chases and a confirmed capture
Across the study, the bats demonstrated a remarkable shift from the common low-altitude insect hunts to two distinct high-energy pursuit events. In both, bats climbed to elevations exceeding 400 meters to spot migratory birds. The hunts featured prolonged, rapid downward chases punctuated by more than 40 successive echolocation buzzes—an unmistakable signature of sustained pursuit of a single target. One hunt did not end in a capture, but the other culminated in the successful capture of a European robin. The event was corroborated by audio recordings of the robin’s distress calls, which were captured during the encounter.
Following capture, the bat yanked the prey into flight, where the bird was dispatched, likely via a lethal bite. The team detected chewing sounds recorded mid-flight, interspersed with ongoing echolocation, indicating that the bat consumed the bird in flight for about 23 minutes without losing altitude. This remarkable behavior demonstrates not only the bat’s hunting prowess but also its ability to sustain a large, complex meal while maintaining flight performance.
What this means for our understanding of predator–prey dynamics
The findings illuminate a specialized aerial predation strategy that few vertebrate predators employ. Only three fast-flying, echolocating bat species are known to exploit the migratory bird resource at night, and the greater noctule appears uniquely equipped for this niche. The study’s analysis of wings and debris beneath hunting grounds—supported by predator DNA barcoding and x-ray imagery—reveals that these bats often remove wings in flight to immobilize large prey, reduce drag, and simplify handling. Such techniques echo aerial-hawking strategies historically associated with large insects, yet here applied to avian prey. This aerial prey handling distinguishes bats from birds of prey and other carnivorous bats, which typically consume large prey while perched rather than mid-air.
Ecological and evolutionary implications
Seasonal nocturnal bird migration creates predictable, high-value foraging opportunities. The greater noctule’s ability to exploit this resource suggests a nuanced ecological balance in European forests, where energy budgets, predator avoidance, and prey dynamics intersect. The behavior may influence migratory timing, stopover ecology, and even the spatial distribution of nocturnal predators. Moreover, documenting such high-altitude hunting expands our appreciation for bat diversity in foraging strategies and underscores the adaptive versatility of echolocation and flight mechanics.
Conclusion: a remarkable aerial adaptation in a changing world
As climate and migratory patterns shift, understanding how top foragers like the greater noctule navigate new food landscapes becomes ever more critical. This study provides the first direct, high-resolution evidence that Europe’s largest bats can and do hunt migratory birds in flight well above the ground, feeding mid-air before concluding their chase. The greater noctule’s success adds a vivid chapter to the story of nocturnal predation and invites further inquiry into how such rare, high-energy hunts influence forest ecosystems across Europe.
