Adit hibernation surveys - National Bat Monitoring Programme
By Nicola Faulks, Jan 23 2019 08:26PM
The first set of NBMP hibernation surveys have now been completed. We had enough people for two teams for the January surveys, including new surveyors, a new pair of waders and a new pair of wellies!
In the highest adit surveyed, we found two brown long-eared bats (both had moved from 23/12/2018) and one Daubenton's bat, we have seen three bats on all counts this year. On 04/12/2018 a Daubenton's bat was found 81m into the adit, on 23/12/2018 one was at 91m (into the adit) and by 12/01/2019 one was back at 81m, in the same spot. I would love to know if this really is the same bat.
Our other well used adit held fewer bats. In January we refound one Natterer's bat which had not moved since 23/12/2018 and a Daubenton's bat in a new crevice. We recorded one Natterer's bat and three Daubenton's bats on 23/12/2018, so we lost two bats, either they were hiding or they had moved.
No bats were seen in three of the usual adits, despite searching one much further than ever before, as the water level is now below wader depth! A bat was found in one of the lower altitude adits, a Daubenton's bat at 43m in, only the second bat ever found in this adit, the other was a Natterer's bat seen in January and February 2015! We have surveyed this adit 15 times now and found a bat on just three occasions.
In the other valley system, on 12/01/2018 the Daubenton's bat was not where we left it in December and was not refound. Team 2 went into a culvert which doesn't get checked much as it never seems to have bats in it; however a brown long-eared was recorded this time! We have surveyed this site in January 2014, 2016 and 2017 and February 2017 and not seen a bat there before.
We also saw a lot of moths, with a total count of 255 heralds and 18 tissues in January (two types of moth!). The highest herald counts in individual adits were 74, 51, 35 and 22 with heralds recorded in all 10 sites surveyed; the tissues were found across 7 adits with a high of 8 in one site.
Thanks to all three teams for your help, what amazing results!