Most bats feast upon night flying insects, fruit, lizards, small rodents, or in the case of the vampire bat by drinking the blood from smaller mammals, etc. It is not common for bats to eat birds. However it was recently discovered that one species in particular might be doing just that. Giant noctules or Nyctalis lasiopterus are among the largest bats in Europe and can often be found flying thousands of feet in the air using their sonar to locate prey beneath them.
Every spring, billions of migratory songbirds in Europe fly north to their breeding grounds. Most of these birds can be found flying at night when there are fewer predators around. However, researchers have recently discovered that the giant European bats mentioned above have been plucking the migrating birds out of the night sky and making them their dinner.
This discovery took place in 2007 when the group of bat researchers spent a night recording the sounds of a marshy Spanish forest. When they played the recordings back at full speed the only thing they could hear were the croaking of frogs. However when they played the recordings back at one-tenth the normal speed, they noticed audible shrieks (the sonar call of the giant noctule bat.)
This giant bat is hairy and brown and has a wingspan slightly bigger than a blue jay’s. It spends most of its time hiding out in the tops of tall trees. It is one of Europe’s largest bats and has a very large mouth full of scary looking teeth. This bat is also one of the least known bats in all of Europe.
It has been well known for a long time that these specific bats feed on flying insects but the discovery of them eating songbirds came as quite a surprise to researchers. In fact, they might be the only bat that eats birds.
It is thought that the giant European bat starts its hunt thousands of feet in the night sky where it can use its sonar calls to lock in on the migrating birds beneath it. Once the giant winged creature locates the bird it swoops in for the kill and wraps the bird between its wings and tail membrane, trapping the bird in a sort of death cage. The bats eat only the profitable parts of the bird such as the breast where the birds accumulate the most fat and muscle.
Once these bats get close to the ground they can be found opening their giant wings and dropping the mangled carcasses below. Although their have not yet been any sightings of this bat eating birds, researchers have confirmed the theory as they have been pulling feathers out of the bat’s feces (guano) for years. Blood and tissue tests also confirm that the birds are a major food source for the giant noctule bats.
Even more interesting were the tests that were performed by researchers. The team compared the different chemical fingerprints that both insects and birds leave in the bats that have eaten them. (Eww). Surprisingly enough, researchers found that in the summer, the bats are only eating insects, but during the spring and fall migrations, they are eating a lot of birds.
While these gigantic bats are far too rare to pose a major threat to the migratory songbird, the bat’s choice of food is still attracting plenty of attention and many scientists find the bat’s diet fascinating. Researchers are continuing their studies and are working with electronic radars in the hopes of catching one of the bats as it hones in on a flying songbird.