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Derbyshire Underground Sites Project; Phase II
This blog gave updates from the autumn swarming trapping project which took place last autumn.
You can read the background to the project on the project background page.
DNA Results Returned
The 26 samples from our autumn swarming surveys have been returned. None of the samples we sent off were returned as Alcathoe's but were all either whiskered or Brandt's bats. This is great news as it means we know that fur clipping is a viable method for obtaining DNA samples so we'll continue with this method next year. It has also confirmed yet more records of Brandt's bat in Derbyshire for us and was well worth doing.
The full results are now being written up in a 2015 summary report which will be available in the coming weeks.
(4th) All Surveys Complete
The final survey for the 2015 project was at Good Luck mine & 8 volunteers braved the cold night air. We had two traps located at Silver Eye mine and two mist nets at Good Luck mine. Another cold night with temperature range of 7°C to 3.5°C. A slightly better evening than the night before with 4 bats caught (3 Natterer's and a Daubenton's). Despite the small number caught, the species trend fits with previous studies that the end of the season is the Natterer's bat mating period.
The next step for the project is to submit the 16 DNA samples for analysis. These are from 'small' Myotis species which are either whiskered/Brandt's/Alcathoe's bats. Once this data has been returned we can start to work on the analysis of the data & subject it to statistical tests. Keep checking back for the results of the DNA analysis!
If we confirm Alcathoe's bat, it will be the first record for Derbyshire & the Peak District.
Above: Surveyor checks the mist net & one of the Natterer's bats we caught (top left) and the single Daubenton's we caught (right). Note the warts on its nose.
(3rd) Penultimate Survey
The fourth & final survey at Owl Hole cave was a very cold affair with the temperature crashing to 0.1°C! Luckily the saturated air meant it kept from freezing.
The pothole was a little warmer with the circle of trees above it. As we're getting to the end of the bat mating season the numbers are starting to decline & with last night's cold weather we caught just 1 Natterer's bat (below).
Above: Surveyors check the harp traps at Owl Hole cave in Derbyshire & the Natterer's bat we caught. Note the warts on its ear.
(29th) Project reaches caving community
On the last weekend of September, DBCG had its inaugral visit to Hidden Earth, the UK's National Caving Conference. Member's Jess & Steve each gave a lecture on the Saturday morning on bats underground and our autumn swarming project.
Both talks recieved lots of questions and raised several discussions about bats underground. We disseminated some of the results from the current dataset (some results will be made available here following the last two surveys next weekend.)
We also had a bat group stand present at the event with lots of free information available for the 300 or so caving delegates at the event including bat cookies baked by Jess!
Above: Our stand at the National Caving Conference, Hidden Earth.
(5th) Dataset reaches 300 bats
On Saturday 5th September we completed the 4th and final survey of Jug Holes cave.
No real swarming activity was observed, there was a steady catch of bats as individuals came to visit the site to see whether any swarming activity was taking place. Importantly we caught our 300th bat of the two-year project during this survey (a Daubenton's).
We caught 21 bats of 5 species:
1 brown long-eared
Project leader Steve is away for the next few weeks so our next survey won't be until Friday 2nd October.
Above: whiskered bat showing the dark inner-ear
(4th) Warm-ish night at Owl Hole
We normally get a bit chilly when surveying at Owl Hole cave given it's exposed nature. However we had balmy temperatures of 10°C on 4th September & a total of 17 bats:
1 brown long-eared
We're seeing more female bats during our catches now as they have begun to leave their summer roosts and visit swarming sites.
Above: a female Daubenton's bat
We've uploaded a short video to show you bats falling into a harp trap. Our next survey is this coming Friday so keep an eye on this page for further updates.
(28th) First Site Completed
Last Friday evening we headed to one of our study sites in the Via Gellia and for the first time this year, we caught 5 species in the same evening. This site has now been surveyed 4 times - the number of surveys per site we're aiming for. We have four more surveys to undertake on the project in total and that will be the end of this year's survey effort.
Above: a brown long-eared bat and the distinctive S-shaped calcar on the tail membrane of a Natterer's bat
(22nd) A good haul
Back to Jug Holes cave on Saturday for survey 3 of 4 and we caught 33 bats.
2 brown long-eared
2 Myotis species awaiting DNA confirmation
1 Natterer's (only the second bat of this species during this year's project)
The Daubenton's swarming season has really kicked off so we are expecting to see a fall in whiskered/Brandt's bat catches as the number of Daubenton's and Natterer's increases.
Top-left - A Daubenton's bat being processed. Bottom: The difference between whiskered (left) and Brandt's (right) bat penis shape.
(20th) Possible New Species
During a survey on a Thursday evening we caught a bat which was a likely candidate for Alcathoe's. This species has not been confirmed in Derbyshire as of yet. We took DNA samples from the bat and these will need sending off for analysis.
During the survey we caught 27 bats:
2 brown long-eared
2 Myotis species awaiting DNA confirmation
The Daubenton's bat mating season has finally arrived with just a few days difference!
(17th) Halfway House
We undertook our 8th survey on Saturday which means each of our sites have been surveyed twice and have two more each to go. It was a cold night with the start temperature at 6°C which dropped away to 2°C by the end. We caught 7 bats (4 brown long-eared and 3 Daubenton's.)
We have undertaken more surveys in August this year as whiskered/Brandt's & Alcathoe's bats swarm earlier than other species and we wanted to collect a dataset from these species. Last year's surveys concentrated on swarming in September.
(14th) Rain doesn't stop play
Despite a poor forecast we headed out to the Matlock area once again to one of our study sites; bats still swarm in the rain if there's a break in the weather. Basecamp was a homely affair with tarps to keep us dry.
The rain got heavy from 11:30pm onwards and at 1am decided enough was enough, but only after we caught 6 bats of 3 species (whiskered, Brandt's and Daubenton's). The total number of bats caught for the project so far this year is 69 & we're out again on Saturday.
Above: Oli & Sam set up the tarps for basecamp Below: Processing a Brandt's bat including weighing.
(10th) Swarming season underway
With a slow start to the catch rates last week, the past three surveys have shown that just one week later has made all the difference. The reduction of the full moon has also likely had a postive impact.
As of 10th August, following 6 surveys at our 3 sites, we've caught 63 bats, almost half of which are Brandt's. Given that there are less than 40 records of Brandt's bat within the DBCG database, this is a really significant find! Species Breakdown:
11 Brown long-eared
4 Myotis species awaiting DNA confirmation
Above: The team process bats and the teeth and nostril of a whiskered bat. Below: The epididymis of a brown long-eared bat (the two black dots either side of the tail bone and the same bat ready for release.
(2nd) All sites surveyed
Over the past week each of out sites have been surveyed once. It's been a good start to the season with four species caught, albeit in low numbers. On Friday 31st July under a blue moon we caught a Brandt's and brown long-eared and on 1st August we caught a whiskered, Brandt's and brown long-eared.
This year we're marking the bats we catch with water-based liquid chalk so that we know how many individuals we catch (see below). The chalk only lasts a couple of days.
Surveys Get Underway
On Saturday 25th July 2015 we undertook the first survey of this year's project. We were at our most northerly site which last year gave us the second-highest catch rate. A chilly night (the temperature dropped to 2°C) meant we caught just a single Natterer's bat. Nevertheless it is still useful data for the project!
So what's happening in 2015?
We have just published our report from last year's surveys, download it by clicking on the image below.
We have renewed the licence for the 2015 period with some minor alterations (these are outlined in the report) and will be continuing with the project this autumn, concentrating on three sites.
We've just purchased a brand new harp trap for the project and have opted for a triple-bank as these have been found to have higher catch rates due to fewer bats flying through the string banks.
The results from 2014 and 2015 will be amalgamated to provide a larger dataset to work with, which in turn will help us understand more about the use of Derbyshire's caves and mines by bats.
Halfway through the 2015 trapping period a couple of members from the project will be attending Hidden Earth, one of the UK's national caving conferences. They will present the 2014 data and what we have from the 2015 period, together with presenting the work DBCG have been undertaking to educate the caving community here in Derbyshire and the progress from that collaboration.