Woodland Bats

Greater Horseshoe Bats © Can Stock Photo, remus20

Greater Horse­shoe Bats © Can Stock Photo, remus20

Ear­lier this sum­mer we had the loan of a bat detec­tor from the Devon Wildlife Trust, which was left in Trera­gin Wood for three days.  More reg­u­lar read­ers will realise that Trera­gin is in Corn­wall, but the Devon Greater Horse­shoe Bat sur­vey includes areas of East Corn­wall close to known breed­ing sites, and we just squeaked in.

Treragin bat records

Trera­gin bat records

My first fear was that I had set up the detec­tor incor­rectly, and that there would be no records, but thank­fully that was not the case.  The results were released recently, and showed a total of 57 bats fly­ing past dur­ing the three days.  Pip­istrelles were the most com­mon, but a sin­gle record for a Daubenton’s bat was a slight sur­prise.  They like still open water, but then again like many species they also like to roost in old mine shafts and work­ings.  And there are plenty of those around Trera­gin!  The Lesser Horse­shoe bat is also quite rare, but we have had a stray one in White Cot­tage before, so that was less unexpected.

I was quite pleased with records, but this was put to shame by a friend, who I had alerted to the bat sur­vey, who had 967 records for his place!  That included three passes by the elu­sive Greater Horse­shoe bat.  He has a small­hold­ing with old species rich flower mead­ows, a stream and lots of mature hedges and sur­round­ing wood­land, so ideal bat habi­tat.  I guess it goes to show that Trera­gin Wood, at a mere 20 years old, still has a way to go to develop a full wood­land ecosystem.

Our woods at Hol­ford are also a spe­cial place for bats, as they form part of a Spe­cial Area of Con­ser­va­tion (SAC) and also a Site of Spe­cial Sci­en­tific Inter­est (SSSI).  The SAC des­ig­na­tion is pri­mar­ily because the old oak woods in the area host Bar­bastelle bats.  Thanks to vol­un­teer bat sur­veys we even know which trees in our woods are used as a roost by the Bar­bastelles.   Let’s hope they don’t fall vic­tim to a gale!

Bats love hollows and cracks in old tree trunks

Bats love hol­lows and cracks in old tree trunks

Harrowbarrow Mine chimney

Har­row­bar­row Mine chim­ney, just up the val­ley from Treragin

We also under­take bat sur­veys as part of our eco­log­i­cal ser­vices, and these are often required for build­ing devel­op­ments that involve con­ver­sions or demo­li­tions.  How­ever, bats used to man­age with­out cosy cen­trally heated attics, and old trees and caves were two of their favoured haunts.  Bat num­bers have sta­bilised after many years of decline, and some of this is due to bet­ter legal pro­tec­tion of roosts.  But as the sur­vey results for Matt’s small­hold­ing empha­sise, the sur­round­ing habi­tats and farm­land are at least as, if not more, impor­tant.  The insects that bats fed on are asso­ci­ated with open water, old species rich flower mead­ows, and indeed mature native wood­lands.  Species pro­tec­tion is no sub­sti­tute for wider coun­try­side con­ser­va­tion.  Hope­fully Trera­gin Wood will become a grad­u­ally increas­ingly impor­tant part of that jigsaw.

Stephen