This video is called Bats in America are dying and scientists are trying to figure out why.
According to Dutch mammalogists, several bat species in the Netherlands are recovering after declines during the twentieth century.
Especially Geoffroy’s bat is on the rise; numbers now are 2000% of the 1986 figures. For Natterer’s bat, this is 1500%. For whiskered bats, 350%.
There were also, not so spectacular, increases for brown long-eared bats (see also here), greater mouse-eared bats, pond bats, and Daubenton’s bats (see also here).
The research results are limited to those seven bat species. Other species, like the common pipistrelle, are more difficult to count, so there are no numbers for them in the survey.