The goal of all this work is to ensure that hibernacula - the most vulnerable of all bat roosts - are protected and also to to contribute as much data as possible each year to the National Bat Monitoring Programme.
Having reached a stage when I've arrived at the bottom of my list of possible sites, when we're running out of winter and when frankly I've seen enough wet, muddy and claustrophobic underground places to last a lifetime, I thought it would be interesting to take stock.
Including surveys of exisiting hibernacula, both in the Lothians and in Dumfries and Galloway, in the past three months I have surveyed:
- 6 limestone mines
- 1 copper mine
- 7 lime kilns (one of them flooded to about half an inch higher than my waders!)
- 2 tunnels
- 4 castles
- 2 soutterains
- 1 WW2 underground bunker
- 2 pill-boxes
- 3 air-raid shelters
Out of all those sites, the following records were made:
- 16 Natterer's Bats (Myotis nattereri)
- 5 Daubenton's Bats (Myotis daubentonii)
- 1 Unidentified myotis bat (Myotis sp.)
- 6 Brown Long-eared Bats (Plecotus auritus)
- 16 Pipistrelles (Pipistrellus sp.)
The frustration is that all the bats were in the sites where we expected to find them. In other words: no, we haven't found any new hibernacula! That said, there are several sites which have strong potential and will be revisited next year. The disappointing result is probably only to be expected. Bats are extremely discerning about sites they use for hibernation: their requirements regarding temperature, humidity, constancy of both and lack of disturbance are very precise. That is exactly why it is so important to find and protect these sites.