The Wilder Side of Vienna

Notes from Nature: May 2010

Columns | R S Hughes | May 2010

It’s approaching 7:30 p.m. as I walk through the Stadtpark, one of Vienna’s most central oases, cocooned by busy roads, hotels, apartments and city life. The sky is a glowering grey-white and it’s raining heavily. Occasional businessmen scurry past under umbrellas, homeward-bound. One holds a newspaper awkwardly above his head in a semi-successful attempt to remain dry.

"It’s probably not the best weather for bats," Ulrich Hüttmeir had warned me in an email earlier in the day. Still, bats are revered in the Stadtpark, where the strains of Die Fledermaus still float through the French windows of Kursalon where Johann Strauss himself would host his legendary dance soirees.

One of Vienna’s foremost authorities on bats, Ulrich meets me under the shelter of the Stadtpark U-bahn station as the last of the day’s gloomy light fades. As we talk, traffic trundles past on the wet roads, drowning our conversation and spraying passers-by. We turn our backs on the city, and wander into the park, now in near darkness and virtually devoid of people.

"I thought this was the best place to come to spot a good range of species," says Ulrich. "We caught more than 20 bats in one night here last year – an absolute record in Vienna."

Austria has 26 species of bat (or maybe even 27, pending scientific investigations into an apparently new species caught in Carinthia recently) and Vienna is home to 21 of them. The city’s smallest is the soprano pipistrelle (Pipistrellus pygmaeus) – a minuscule 4cm fuzz of rusty brown/black fur with a wingspan of about 20cm. At the other end of the spectrum is the greater mouse-eared bat (Myotis myotis), a comparative colossus with a wingspan of around 45cm and, as its name suggests, prominent, mouse-like ears.

Austria’s bat numbers declined massively during the 1960s and 1970s, due mainly to the use of insecticides and pesticides, but thanks to today’s increased awareness, their protected status and to some extent to climate change (bats like it warm), the numbers of most species are growing again. Some remain critically endangered though; five or six thousand long-winged bats would winter in Austria in earlier times, but by the mid 1990s, numbers had dwindled to just six individuals. "We hope they are coming back now," says Ulrich.

The rain eases and we saunter towards Ulrich’s preferred viewing spot – a central ornamental lake – through puddles full of floating tree blossom and over wooden bridges so wet they shine when caught in the light of the Stadtpark’s lantern-like lamps. He turns on a small electronic device to detect the ultrasound echo-location calls – only very young girls have keen enough ears to hear the high frequency calls of some bats without help.

For a few moments we are silent. Mallards drift gently on the water and a rat scuttles across the path behind us. We’re listening for the da-da-da of the device, as it detects bats hunting for insects over the water.

"These detectors are very interesting," says Ulrich. "If you record and slow down the social call of a nathusius bat by a factor of 10, it’s very melodic, almost like bird song. I’m always lucky when I find this on my recording."

We have no such luck tonight. It seems that Vienna’s bats, only recently woken from their long winter hibernation, have decided to conserve energy and stay at home in hollow trees, holes in buildings, attics and lofts, and under bridges and tunnels across the city. "I think it’s very unlikely that we’ll see or even hear a bat tonight," says Ulrich eventually, lighting up a cigarette in resignation.

As we say our goodbyes, Ulrich invites me to a bat walk he’ll be hosting later in the year. "Let’s meet again when it’s a little bit warmer," he says.


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