I met slightlyfoxed at Honor Oak Park, and we partook of sourdough pizza while waiting for the witching hour of 9PM. Then we joined a motley group of bat enthusiasts and our personable leader, who announced "You're all here for the slug walk, right?" and informed us that if we were really lucky, we might see two leopard slugs mating.
This was followed by ninety minutes of tramping through increasingly dark woodland, stopping at likely bat haunts to listen to the crackles of the bat detectors (radios) in hopes of hearing squeaks.
The bats weren't very cooperative, possibly because the moths weren't either. In one clearing we heard a fusillade of chirps, but I missed the single pipistrelle which subsequently shot overhead. Later there were lower-frequency sounds which the leader explained were probably made by a larger bat, perhaps a noctule or rare Leisler's. We waited in the hope that it would return, but it didn't.
It was a lovely evening, though, and I learned lots. For instance:
- Common pipistrelles transmit at 45kHz while soprano pipistrelles are on 55kHz
- There is only one known example of the mouse-eared bat in Britain, and he's probably a bit lonely
- Bats are massive mansluts: it's not uncommon to open a bat box and find one male with a harem of six or seven females
- You need to do 200 hours of volunteer work to get a bat-handling licence
We also admired the twinkling lights of London from a gun emplacement constructed during the First World War to take pot shots at Zeppelins. What an ace park!