In-flight meal

Natural History, Dec, 2001 by Erin M. Espelie

Though bats and birds are both aerial creatures, records of their interaction have been extremely rare. Carlos Ibanez, of the Estacion Biologica de Donana in Seville, Spain, and fellow researchers have demonstrated that a large, carnivorous European bat is interacting regularly with certain groups of birds. In a massively messy undertaking, these scientists have sifted through 14,000 guano samples from the bat species known as the greater noctule (Nyctalus lasiopterus), hoping to identify what the bats were feeding on every night: flies, moths ... birds? They found that the bat droppings contained quite a few feathers, particularly during the two periods a year when flocks of small passerines make their seasonal migrations, mainly at night, through the bat's Mediterranean domain.

A few species of tropical bats occasionally capture and consume roosting birds, but N. lasiopterus is the only bat now known to regularly prey on birds in temperate climates. It may in fact hunt and attack a bird while both animals are in flight.

Ibanez's group studied the wing shape and sonar patterns of the greater noctule and found that they differ significantly from those of other carnivorous bats. N. lasiopterus has a long, low-frequency echolocation call, making it well equipped for detecting airborne prey at considerable distances. In addition, the wings of the greater noctule--designed for speed--lack the maneuverability that would be required for hunting a bird in a confined nesting space. According to Ibanez et al., this rare bat made an easy transition from hunting large insects to capturing small birds in midair. ("Bat

Predation on Nocturnally Migrating Birds," Proceedings of the National Academy of Sciences 98:17, 2001)