For the past week we’ve been mist netting for bats, mainly Lesueur’s wing-gland bats (Cistugo lesueuri) at the Sterkfontein Dam and Nature Reserve in the Free State Province of South Africa which lies on the northeastern side of the Drakensberg Escarpment, about a four-hour drive southeast of Pretoria. The Kingdom of Lesotho lies west of the Drakensberg mountain range. It’s a tiny nation of about 2 million mainly Basotho people atop the windswept escarpment, reached by four-wheel drive vehicles on only the one road. The African subcontinent’s highest peak is Thabana Ntlenyana (beautiful little mountain) in the Drakensberg Mountain Range, an impressive 11,417 feet (3,480m) above sea level.
Each night we set up multiple nets in different parts of the reserve that look like they have potential for finding our bat. But winter is setting in, and we’ve been hammered by gale-force winds and temperatures around 40 degrees F (4 C), conditions where most bats are not active.
Twice we mistook a Cape serotine (Eptesicus capensis) for a Lesueur’s wing-gland bat (Cistugo lesueri), only to find out the disappointing truth upon closer inspection back at our chalet. The two species are easily confused in the field, however they actually belong to different families. The genus Eptesicus is found nearly everywhere and belongs to the family Vespertilionidae. Cistugo has recently been recognized to represent a new family, the Cistugonidae. Despite its distinctiveness, based on skull and genetic characters, it is only recognizable in the field by its pointed tragus, compared to the blunt ones of Eptesicus, sometimes not easily seen in a very small bat when being extracted from a mist net. Merlin has already photographed all 18 of the world’s other bat families, so he wanted to add this one once it was recognized.
These bats have seldom been caught, and previously only in South Africa’s summer. We hoped to still find them in fall. Unfortunately, the cold weather arrived early, precluding our ability to find them despite the expert and tireless efforts of our South African colleagues: Ernest Seamark, Teresa Kearney, Johan Watson and Leon Labuschagne. It’s difficult to imagine having a better informed, harder working team. Night after night they led netting efforts, often under extremely miserable conditions. Last night Merlin was forced to wear both his down vests, a long-sleeved fleece, long underwear and a windbreaker, and he was still cold. All of us were! Thanks to our wonderful and much appreciated team, Merlin was able to photograph four species, despite trying circumstances.