Return of the bat: European species make a comeback

 Defying years of shrinking habitat and disappearing roosts, #bats are making a comeback in #Europe.

#Bat numbers – collected from 6000 hibernation sites in nine #European countries – have increased by 43 per cent between 1993 and 2014, according to a new report by the European Environment Agency (EEA). The study, which tracks 16 of Europe's 45 bat species, is the most comprehensive population study of #bats on the continent to date.

"This trend is a definite sign of hope," says Karen Haysom, director of science at the British Bat Conservation Trust, a partner in the study.

Armed with a statistical method that proved key in earlier EEA studies of European butterfly and bird population trends, Haysom and her collaborators input decades of national bat data into a dataset that revealed how bat numbers changed from winter to winter according to species and region. Never before had such data – reported by scientists and also by thousands of amateur bat enthusiasts, who counted hibernating #animals in local caves and other roosts – been consolidated over such a broad time span and geography, Haysom says.

"This is giving us a chance to put our numbers in a different and very valuable context, and think about why some bat species are doing well in some countries compared with others," she says. Population trends were calculated in Latvia, Hungary, The Netherlands, Austria, Portugal, Slovenia, Slovakia, Germany and the UK.