August 16, 2001. Copyright, 2001, Graphic News. All rights reserved

Bats favour birds as fast food treat
By Elisabeth Ribbans

LONDON, August 16, Graphic News:  MILLIONS of small birds that make the long seasonal migrations between tropical and temperate climes risk ending up as a late night snack for EuropeÕs biggest bats, according to startling new research conducted by scientists in Spain. Until now, a mere handful of the worldÕs 1,000 bat species had been known to prey on birds Ð and these were mainly tropical varieties that might occasionally capture a creature at rest. But a study just published in the U.S. journal, Proceedings of the National Academy of Sciences, suggests that the greater noctule bat Ð Òone of the rarest and least known mammals in EuropeÓ Ð actually chases, catches and eats large numbers of small birds, such as robins and wood warblers, on the wing.

Carlos Ib‡–ez, who conducted the research with colleagues from the Estaci—n Biol—gica de Do–ana in Seville and the University de Alcal‡ de Henares in Madrid, says millions of small birds cross the worldÕs temperate regions during migration, mainly at night, but Òno nocturnal predators had been known to benefit from this enormous food resourceÓ. The team believes this first evidence of bats preying regularly on nocturnal migrating birds Òopens new perspectives to the study of evolutionary interactions between [the two species]Ó.

The greater noctule (Nyctalus lasiopterus), which lives in southern Europe, is one of the largest aerial-hawking bats in the world, with a wingspan reaching 45 centimetres. Although it was thought Ð like most bats Ð to feed exclusively on insects, Ib‡–ez says it could easily overpower small birds flying at night. Because its echolocation frequency is far above the birdsÕ audible range, it can surprise its prey without being detected.

The scientists made their discovery by analysing 14,000 droppings from around 250 bats in Spain. During the March-May and August-November migration periods, abundant bird remains were found in the faeces. Compared with other known carnivorous bats, which forage for resting birds and carry the quarry back to the colony for consumption, the shape and form of the greater noctuleÕs wings is geared to fast pursuit in open areas rather than agile attack in cluttered habitats. The important findings come, incidentally, in the International Year of the Bat.
/ENDS

Sources: Bat Conservation Trust (UK), UN Eurobat programme