OREANDA-NEWS. August 13, 2015. It’s not a problem commonly faced by energy companies, and it’s left staff at Invergarry power station feeling – quite literally – left out in the cold.  The 12-strong SSE hydro workforce has been ‘evicted’ from the station’s mess building for the past three years thanks to some uninvited little guests: many hundreds of soprano pipistrelle bats.

Over 500 of the furry, flying mammals have taken up residence in the walls and roof space of Invergarry hydro’s mess building, only a few hundred feet from the 20MW power station which sees water carried from Loch Garry by a tunnel near the mouth of the River Garry on Loch Oich, before being churned through the plant’s generators to generate electricity. 

Emerging at dusk every summer evening to feed before returning to their mess room roost at sunrise, the bats lodge themselves in tightly to create warmth.  A negative side effect of the bats’ presence however is the overpowering smell of ammonia given off by their droppings: extremely unpleasant for human noses!  So bad is the problem that SSE’s Invergarry team has resorted to hiring a portable cabin in which to spend tea breaks and down time to escape the overpowering stench in summer months.  This is proving expensive as time goes by and is not a long term solution when the newly-built, permanent mess room is right next door and lying dormant other than as a summer house for bats.

This year, SSE’s dedicated wildlife biologist Alastair Stephen has risen to the challenge of relocating the soprano pipistrelles, working under the close supervision of SNH and with expert help from bat ecologist Robert Bell of Ecus Ltd.  To allow the exclusion of bats from the mess room a licence must first be obtained by SNH. It is essential the bats are not left without a home and to this end a replacement roost structure, comprising a small hut, is being designed for construction on the banks of Loch Oich. To further encourage the bats to utilise this new accommodation, three small bat boxes have been placed on adjacent trees and the new roost building will be primed with bat droppings taken from the existing mess building to create a distinctive ‘bat’ aroma!

With the licence in place, the soprano pipistrelle roost in the mess building will be closed in winter 2015-2016, when the bats are absent.   The mess building also supports a trouble free brown long-eared bat colony, which roosts in the roof void, an area not used by the pipistrelles. New openings from the exterior into the roof void will be built to allow continued access for the brown long eared bats in future years. Through our preferred approach of retaining bat roosts where they present minimal issues, whilst constructing replacement facilities to allow exclusion of problem roosts, SSE is doing its bit to protect Scotland’s bat populations. 

Alastair Stephen said:

“A key priority for us is to ensure the bats are relocated safely and without disruption to their natural behavioural patterns.  SSE has enlisted the help of SNH and Robert Bell from Ecus Consulting to advise on and manage all aspects of the procedure.  SNH is the gatekeeper of the bat relocation process and Robert is experienced at conducting what is a very delicate and specialised procedure.  My day job tends to focus on fisheries management for SSE to ensure our hydro plant is working in harmony with native salmon populations and other aquatic wildlife interests, so dealing with the bats is slightly different but immensely interesting.  Our Invergarry team will also be thankful to be reinstated in their own mess room before too long”.

Robert Bell of Ecus Ltd said:

“It’s great to see companies like SSE taking a creative and responsible approach by undertaking best practice procedure for bat relocation.  I am excited to be a part of this particular process at Invergarry where SSE has one of the biggest roosts of soprano pipistrelles I’ve ever encountered.  Bats comprise a range of hugely important species worldwide and protective legislation of the highest level rightly exists across the UK to protect this unique mammal, which has suffered historic declines in abundance.  Scotland tends to have larger roosts than England – it’s not really known why but is likely to do with either differing weather conditions or a lack of roosting opportunities. Much is still unknown about the mysterious behaviour of bats and surveys being undertaken at Invergarry help us understand the character of the existing bat roost in order tod design an effective mitigation approach for this species .  The process also enables important commercial practices like electricity generation to coexist in harmony with the wonderful wildlife in this part of the country”.