As I'd not surveyed the roost for over a week I thought I would tonight. So I checked it after work and could still hear bats inside, although quieter than usual.
With sunset at 21:16 I arrived at 21:07. The first bat left at 21:19 and by 21:30 I'd had 30 out and thought that was it. But they just kept popping out, so I stayed on. By 22:23 - 75 ! (SEVENTY FIVE!) had left the roost and still noises were coming from the roost.
At 21:55 one bat flew back to the mouth of the roost, then dropped away, seconds later another or the same bat then re-entered the roost and moments later it or another left the roost (I did not count this second exit).
I could also clearly see 2 'myotis' bats feeding above and in the canopy. Strangely though I didn't detect any pipistrelles?
My highest ever count of the roost was 57 on the 1st of June, with the average count being under 30. So does this mean the 30 ish have all had a pup each? Or, I've not stayed at the roost long enough to count the bats out after the first main batch has left? Answer on a postcard please.