I had the privilege today of hearing a fascinating presentation by John Haddow of Central Scotland Bat Group about the Nietoperek Bat Reserve in Poland.
Nietoperek is something of a legend in the bat world: a massive underground system of world war 2 fortifications: with 32 kilometres of tunnels, an amazing thing in itself. But what really adds the thrill is the fact that they are used as a hibernation site by mind-boggling numbers of bats.
For several years John has been taking part in the annual census of hibernating bats, when a large group of skilled bat-workers from across Europe come together to count the bats in the tunnel system. The numbers are incredible: over 30,000 bats were present this year. The predominant species are Greater Mouse-eared Bats (Myotis myotis), with many other species represented, including Daubenton's Bat (Myotis daubentonii), Natterer's Bat (Myotis nattereri), Brown Long-eared Bats (Plecotus auritus) and Barbastelles (Barbastella barbastellus).
Why do they gather in such huge numbers and (more importantly for us!) why don't they do so over here? The numbers of bats we see in Scottish hibernacula are tiny by comparison! According to Frank Greenaway, it's all a matter of our Atlantic climate versus the continental climate of Poland. Put simply, it gets a lot colder in winter in Poland and stays that way for longer, so bats have a greater imperative to find an underground site with a stable temperature.
I also came across a wonderful new word: Chiropterology: The visitor centre near Nietoperek is called The Chiropterological Information Centre. I now know what to say when people who know nothing of ecology ask what I do for a living: I'm a chiropterologist!
The Chiropterological Information Centre: http://www.mos.gov.pl/strona/pl/cicinfouk.htm
Frank Greenaway's video on bat torpor: http://www.nhm.ac.uk/nature-online/life/mammals/webcast-torporinbatsvid/no-mamm-torporinbatsvid.html
This site describes a visit to Nietoperek: http://www.iol.ie/~corkbatgroup/Nietoperek.htm
My website: http://plecotus.co.uk