RRCPC Newsletter
Volume 45 Number 1 Article 2
March 2008

Autumnwatch

Live broadcast from a Cave

On Monday November 12th BBC Natural History Unit broadcast live from Link Pot, part of the Ease Gill Caverns system. The sequence of links from the entrance and inside the cave was shown as part of the Autumnwatch series on BBC2 and featured hibernating bats in the cave. The presenter Simon King was seen descending the 15 metre pitch on SRT and on arrival in Hylton Hall in Link Pot he interviewed Prof. John Altringham from Faculty of Biological Sciences at the University of Leeds. The BBC used Bullpot Farm as a base on the 11th-13th November and worked with members of the Red Rose Cave and Pothole Club and John's research team to set up the programme. We think this is the first live broadcast from a properly wild cave in the UK although research has shown that there was a Wookey Hole Show Cave live broadcast on the Noel Edmunds show - not only live, but of a cave dive as well. That was 1986 - See Descent (73) p33.

Andy Hall was first contacted back in September by the BBC production team with a view to the BBC using the Farm as a base. He spoke to Chris Howard and Martin Hughes-Games who had worked on the recent caving programme "Ultimate Caves" featuring Kate Humble and Steve Backshall caving in various locations across the country. The BBC needed a base for their equipment and personnel during the broadcast and the rehearsals due to take place on the Sunday. The club was happy to help out with this and the landowner was contacted for his permission, which was readily given.

One challenge for such a location was that after a site visit it was found that it was not possible to get a direct satellite link from the entrance of Link Pot. This meant running fibre optic cables for almost 2 kilometres across Casterton Fell from Bullpot Farm to the entrance. It would be dark at the time of transmission requiring the setting up a surface location at the entrance with studio lights etc. All this meant lots of gear to be transported to the entrance and returned afterwards.

The initial idea as mentioned to John Altringham was to film bats swarming at the entrance (see Descent 187, pp 20-21), but November was a little too late in the season for this behaviour. John suggested that a descent of Link Pot to see hibernating bats would make equally good TV (provided the bats were there!) From his earlier research he was fairly sure he would find some.

John and his team have good evidence now that at least five species of bat (Natterer's, Daubenton's, Whiskered, Brandt's and brown long-eared) use the Ease Gill system (and many other caves in the area) in the autumn for mating (when they gather in substantial numbers after dark, making temporary visits from their summer roosts) and in the winter for hibernation (when most of them are well hidden). The team has found roosting bats or evidence of bats in virtually every part of the system they have examined.

They are most likely to be seen near entrances (in the first 100 m or so), but they can be seen far into the system, in places such as the Graveyard Series, the Earby Series and Easter Grotto. The most numerous species is Natterer's bat, but the other species are not uncommon. Bats are caught and ringed in the autumn at entrances - by far the most effective method - to estimate population sizes and follow movements. Ease Gill Caverns has a visiting bat population that runs into thousands, perhaps as many as ten thousand, with several hundred turning up at each of the major entrances every night. Bats ringed in the Ease Gill area make these nightly journeys from as far away as Lancaster and Long Preston and probably a lot further.

On the Sunday morning a large group assembled at Bullpot Farm and vast amounts of communications gear was sorted out ready to be carried over to Link Pot. Meanwhile Tim and Pam Fogg had arrived from N Ireland. They were to deal with the Health and Safety aspects of rigging the entrance pitch of Link plus getting the BBC team consisting of Simon King and cameraman down the pitch. Simon needed to brush up on his SRT skills so one of the trees at the Farm was used for some SRT practice. John had brought some of his PhD students with him to help carry gear and several Red Rose members were also available to help out as well. After several trips across the Fell all the cable had been laid, the pitch rigged and all the gear needed was at the entrance. Simon King descended the pitch without much difficulty and John and Anita Glover (one of his team) had found some bats only 20 metres from the bottom of the pitch.


John Altringham and Tim Fogg at the entrance to Link Pot


Just some of the gear needed at Link Pot for the outside broadcast

During the broadcast John was able to explain to Simon how the bats use the cave system as a hibernaculum during the winter months from November to March. During this time their body temperature drops to that of the cave ambient temperature: in Link Pot this can be as low as 4°C. Their heartbeat drops to only 10 beats per minute, compared to 1000 beats per minute when they are active. They may breathe as infrequently as once every 90 minutes. The end result is a metabolic rate so low that a couple of grams of stored fat will fuel them through the winter. It was also shown how mating can take place during hibernation, with the females knowing little or nothing about it!

On the evening of the broadcast all went well as the weather was cold but dry. Much of the gear was carried back that night and the work completed by next morning. The BBC expressed their gratitude for the sole use of Bullpot Farm for the three days, especially as the weather was at times very cold and wet, and the help given by members of the Red Rose.

Andy Hall & John Altringham
Photos by Andy Hall

Volume Contents

Main Contents