John Schmitt

By studying 14,000 fecal pellets of the greater noctule bat, scientists have made a startling discovery: these European bats apparently capture and consume night-migrating birds in midair.

Until now, no bat was known to capture birds in flight, although as many as four different species may occasionally seize birds at rest.

Researchers in Spain found that as many as 70 percent of greater noctule bats had abundant bird remains in their droppings during songbird migration, apparently capitalizing on the millions of birds flying across the Mediterranean en route to Africa each autumn.

Although greater noctules are the largest bats in Europe, they weigh only 50 grams and probably prey on the smallest songbirds. Researchers discovered one bat with the feathers of a European Robin in its claws. They also found a freshly cut wing of a European Robin and a Wood Warbler on the ground where the bats were captured.

The greater noctule is one of the rarest and least-known mammals in Europe. And because it hunts birds migrating in darkness at heights of up to 500 meters, no one has directly observed the aerial feasts of bats on birds.

Although Eleonora’s and Sooty falcons prey on migrating birds in the same region, greater noctule bats are perhaps the most stealthy of the aerial predators: they hunt in the dark and hone in on songbirds using echolocation frequencies too high for their prey to hear.

—Miyoko Chu

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