Bat Survey Report
Introduction
Historically there have been recorded colonies of bats at Creswell Crags over the
last forty years which have occupied various habitats including the caves, cliffs,
timber structures within Crags Meadow and the Visitor Centre building. A large
colony of pipistrelle bats used the roof space within the original Visitor Centre since
the 1980s with colony numbers peaking to about 380 bats.
In the light of the development proposals to construct a new Museum and Education
Centre at Creswell Crags in 2009 and demolish the old centre, mitigation measures
were put in place to encourage the bats to return and use the new Museum building.
These included the installation of a number pre-fabricated bat boxes on the roof,
small pockets created out of sheet zinc also installed on the roof, and slots leading to
designed cavities behind the wood panelling.
Surveys Post – Building Construction
Since June 2009 regular surveys have been undertaken for signs of bat recolonisation. Surveys have included general inspection of the building perimeter and
during routine maintenance of the roof as well as regular emergent surveys which
have been conducted largely between March and September.
The routine surveys have been conducted by licensed bat workers (Derrick Eames /
Janet Eames) and when more detailed surveys have been required they have been
accompanied by Museum staff who have monitored bat activity by recording
presence / absence by the distribution of bat droppings as well as counting emerging
bats.
Monitoring Results
Bat Box Locations
Mitigation measures to encourage a re-population of the Museum building included
the installation of four Schwegler boxes located on both sides of the parapet wall
above roof level in the proximity of the staff entrance and two Schwegler boxes
located on the parapet wall above the shop. The location of these boxes requires
safe roof access using a man-safe system and therefore have not been inspected as
regularly as locations accessible from ground level.
The pair of boxes at location 1 (Figure 1) facing south west. These were monitored
during the emergence survey on the 2nd September 2010 and there were three bats
recorded emerging from the right hand box. An accumulation of bat dropping was
evident beneath the both boxes and it was clear that there had been sustained
activity by Pipistrelles. This is possibly Pipistrellus pygmaeus, the species that
occupied the roof space roost within the old visitor centre.
The adjacent pair of bat boxes at location 2 (Figure 1) facing north east. These were
inspected during a routine roof inspection and maintenance call to attend a faulty
actuator on a roof light on 7th April 2012. Although no bats were observed during the
inspection a small accumulation of droppings was evident indicating that the boxes
did have infrequent use by one or two bats.
Oak Panel Slots
The building design incorporated a series of slots within the external timber panelling
leading to small cavities created utilising the rear part of a Schwegler box behind
each slot location.
Three slot entrances at location 11 (Figure 1). During the emergence survey on the
2nd September 2010 one bat was observed leaving the right hand slot.
A further six slots at locations 5 and 6 (Figure 1) on the north east facing side of the
building. During the survey on the 2nd September no bats emerged from these
locations but the accumulation of droppings noted throughout the summer indicates
regular use by Pipistrelle bats, again most likely the P. pygmaeus colony from the
original roost.
Zinc Pockets
On the north section of roof the building design included three pockets created from
additional sections of zinc sheeting at locations 7, 8, 9 (Figure 1) creating a small
internal cavity.
Surveys to date have indicated no bat activity at these locations.
Non-Designed for Locations
During survey work around the building perimeter at dusk it appears that bats are
exploring all edges of the building as possible entrances into available roost sites
within roof voids, especially where the zinc roofing sheets lips over the wooden clad
perimeter walls. Activity is particularly evident at locations 4 and 10 (figure 1).
Early survey work suggested that the majority of activity is on the north east side of
the building at locations 5 and 6 (Figure1) and frequent activity all along the roof joint
at location 10 (Figure 1). A large accumulation of droppings was observed on the
ledge beneath the north east corner of the building adjacent to the bottom of the
steps in that area. Further investigation indicated that three bats were roosting in the
crevice between the roof lip and the wooden cladding. The limited view of the bats,
the proximity and the size and shape of the droppings indicated a potential
Daubentons (Myotis Daubentonii) roost site.
During the emergence survey
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conducted on 2 September 2010, a total of six bats emerged at this location.
A sizeable accumulation of droppings was also observed at location 13 (Figure 1)
below the recess to the right hand side of the main entrance. The droppings were
observed during the early part of the year in 2009/11 but that activity decreased
rapidly after 3 – 4 weeks.
During 2011 a new area was discovered with evidence of bat activity at the corner of
the building adjacent to the bin store at location 12 (figure 1). Varying amounts of
droppings were observed on several occasions which steadily increased through the
summer, several emergence surveys concluded the presence of 118 bats and the
roost did not disperse until the second week in September.
The colony has re-appeared this year with the first signs of droppings being noted 4th
May 2012. This timing coincides with previous records and frequent monitoring will
hopefully establish this is the original colony. There was a distinct pattern of activity
with the original colony, towards the end of the season we will know if our suspicions
are correct.
Planning Application 12/00117/FUL - Installation of photovoltaic panels to
south facing roof slope, Creswell Crags Visitors Centre.
A proposal has been submitted to install photovoltaic panels to the south facing roof
space immediately above the exhibition room of the Museum and Education Centre.
The panels would cover an area of approximately 135m² and raised off the roof
surface by 0.3 metres.
Assessment and Mitigation
To date the only new bat activity this season has been at location 12 (Figure 1) and it
is anticipated that activity will become evident in the near future at the other locations
noted.
All of the droppings observed at location 2 (Figure 1) were old and related to activity
from 2011. Unfortunately these bat boxes were not monitored during 2012 and
although activity may become evident it is likely to be minimal as the boxes aren’t
sited in a particularly favourable position.
The location and siting of the proposed photovoltaic panels would not block or
restrict any flight paths of bats emerging from the bat boxes, as the amount of free
fall for emerging bats will not result in the bats flying too close to the panels.
Access to the bat boxes and monitoring of bat activity might be restricted depending
on the final location of the panels and it is recommended that at least a 2 metre strip
of roof be left unobstructed along the side of the roof section from the roof parapet to
enable access (an access strip in excess of 2 metres is indicated on the plans. In
addition it is recommended that a barrier should be erected along the edge of the
panels closest to the bat boxes to create an obstacle that will make bats aware of the
panel locations.
No other bat activity was evident within this section of roof and it is suggested that
this proposal presents no impact on existing or future bat populations within the
building.
Immediately prior to the installation of the panels a survey will be conducted to
ensure no bats will be disturbed. In the event of bats being discovered further actions
will be considered.
Creswell Heritage Trust
May 2012
Figure 1. Aerial View of Museum and Education Centre and locations of bat activity.
Location 3
Location 4
Location 13
Location 5
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Location 9
Location 8
Location 6
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Location 7
Location 2
Location 1
Location 12
Location 10
Location 11