This video says about itself:
This stunning slow motion footage shows how bats use echolocation to find water. We know how bats echolocate to hunt insects, but this is the first study to show how they recognise large, flat objects like ponds. Moreover, by testing young bats that had never encountered a pond or river before, the researchers showed that bats seem to have a built-in ability to recognize these important features of their environment. Read the original research paper here.
Translated from Dutch news agency ANP today:
Things are going better again for bats in Europe. Their numbers have increased between 1993 and 2011 by 40 percent, after years of decline. According to a study by the European Environment Agency (EEA), a research group of the European Union.
In the second half of the 20th century the flying mammals suffered much from agricultural intensification, deforestation and destruction of their sleeping roosts, causing entire colonies to be exterminated. Also, many bats succumbed to the toxic dieldrin, a substance for making timber for housing insect free, banned in 2004.