In the autumn of 2011, bat migration was monitored there.
The report about this says that 65 migrating bats were recorded.
All of them Nathusius’s pipistrelles.
This is a Dutch language video on Nathusius’s pipistrelles and common pipistrelles.
ScienceDaily (Feb. 20, 2012) — A distinctive echolocation frequency led to the discovery of a new species of bat within the genus Hipposideros. Although this bat is similar to the species Hipposideros armiger, differences in acoustics, size, and DNA between these bats led to the identification of the new species. This new member of the bat community, which has been found in two locations in Vietnam, has been given the scientific name Hipposideros griffini: here.
Strange New Leaf-Nosed Bat Found in Vietnam: here.
Bat World Sanctuary Earns Verification from the Global Federation of Animal Sanctuaries: here.