This video is called Bat (Common Noctule) drinking water.
Translated from the Dutch Mammal Society:
Monday, July 16, 2012
During the weekend of 29 June to 1 July 2012, the Mammals Working Group of South Holland province and the Field Working Group of the Mammal Society organized a bat weekend on Voorne island. The aim of the weekend was to detect and count maternity colonies of arboreal bats. Particular attention was paid to the common noctule bat, a species that has some times been observed foraging on Voorne, but which traditionally is lacking on Voorne and on the islands of Zealand further south. During the weekend, eight maternity colonies of bats were found in old trees.
Most colonies were present in an old tree-lined avenue on the northern edge of the estate Mildenburg owned by the South Holland Conservation Foundation. No less than three trees were used by common noctule bats, at least thirty animals totally. The remaining colonies were Daubenton’s bats‘. Besides Mildenburg and Reigersnest estate, two colonies of Daubenton’s bats were found on the small estate Olaertsduyn.
It is the first time that common noctules’ colonies have been found on Voorne. The species seems to expand its range along the coast and seems to be able to find the relatively isolated old trees from the vicinity of The Hague.
Dutch wind turbines and bats: here.
Common noctules — one of the largest bat species native to Germany — are searching for their fellows during their hunt for insects above farmland. Scientists show that bats forage on their own in insect-rich forests, but hunt collectively in groups over insect-poor farmland: here.