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___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
1
Bat Surveys of Hurn Forest Dorset
For
Hurn Parish Council
Report Author
Colleen Hope, BSc, MCIEEM
Surveyors Colleen Hope & Dr Paul Hope BSc (Hons), MCIEEM
January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
2
Bat Surveys of Hurn Forest Dorset
Contents
Executive Summary 1
1.0 Site Overview & Background 2
2.0 Survey Methodology 4
3.0 Survey Results 8
4.0 Evaluation 12
5.0 Recommendations 19
6.0 Conclusions 22
7.0 References 23
Appendices
Appendix 1 Surveyor Experience
Appendix 2 Legislation & Policy
Appendix 3 Status & Distribution of Species Encountered
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
1
Bat Surveys of Hurn Forest Dorset
Executive Summary
Hurn Forest lies to the northeast of Bournemouth in Dorset, just west of the New
Forest National Park. Hurn Parish Council (HPC) manages a 370ha area of
predominantly coniferous woodland and heathland. HPC have appointed various
ecological specialists to conduct a Biodiversity Audit of the site.
Ecological Consultancy Services Ltd (ECS) was appointed by HPC to undertake
bat surveys of Hurn Forest. ECS conducted three capture surveys and two
transect routes over a total of four evenings between May-September 2013. A
total of seven bat species were confirmed to be present including a single male of
the rare species of Bechstein’s bat Myotis bechsteinii.
This report presents the methodology and results of these surveys. An overview
is given of the value of the habitats present within the site for bats together with
some observations on how future management could improve habitats for
foraging and roosting.
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
2
1.0 Site Description, Background & Overview of Proposed Works
1.1 Site Description
Hurn Forest encompasses an area of 370 ha comprised mainly of coniferous
plantation and heathland. The site is long and relatively narrow (approximately 5
x 13km). It is in proximity to residential areas and wider tracts of Forestry
Commission owned woodland and heathland. A wide gravel track runs
north/south through the site. There are two car parks (one at the north and one at
the south end) and the site is in regular use by dog walkers and cyclists. There is
a holiday park adjacent to part of the north west of the site. Bournemouth
International Airport is situated within 0.5km to the west.
The Moors River Site of Special Scientific Interest (SSSI) runs along much of the
western perimeter. Small streams associated with this watercourse flow across
the site towards its northern end. Part of Hurn Common SSSI is also within and
adjacent to the site. The Avon Valley Special Protection Area (SPA), Ramsar site
and SSSI is within 1.5km to the east of the site and the New Forest National Park
within 2-3km. Dorset Heaths Special Protection Area (SPA), Special Area of
Conservation (SAC) and Ramsar site are situated approximately 5km to the west.
The location of the Hurn Forest is shown on Map 1.
1.2 Background
Ecological Consultancy Services Ltd (ECS) was appointed by HPC in spring 2013
to undertake bat surveys of the site. HPC (with funding from other partners1)
have appointed a number of specialist ecologists to survey species and habitats
such as birds, reptiles, invertebrates and flora in order to feed into a Biodiversity
Audit of the site. SW Environmental is managing the ecology team and reporting
back to the parish council. The data will be used to inform future management
with particular respect to the woodland and heathland elements of the site.
1 Bournemouth Airport Community Fund, Lottery Awards for All & The Forestry Commission
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
3
Map 1 To Show Site Location
Ordnance Survey © Crown copyright (2007) All rights reserved. Licence number 100050545
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
4
2.0 Survey Methodology
2.1 Survey & Reporting Standards
Surveys & assessments were undertaken with reference to Bat Conservation
Trust2 (BCT) and Natural England survey and mitigation guidelines3 and conform
to the Chartered Institute of Ecology & Environmental Management (CIEEM)
assessment and reporting standards4. Information on surveyor background and
experience is provided in Appendix 1. Appendix 2 provides details of legislation
and policy relating to bats.
2.2 Desktop Research
A data search of bat records from within 2km of the site was commissioned from
Dorset Environmental Records Centre (DERC) by SW Environmental in spring
2013.
2.3 Visual Assessment of the Site
The site was visited on 6 April 2013 by Colleen Hope of ECS. The majority of
tracks and paths were walked noting key changes in habitats from coniferous to
deciduous woodland, healthland and pasture fields/riparian habitats. The site visit
and Forestry Commission Stock Maps were used to design two transect routes
for subsequent detector surveys. These aimed to encompass as much of each
habitat type as possible including potential foraging areas and commuting routes
whilst gaining coverage across most of the site. Each transect route was
designed to take 90-120 minutes.
Time did not permit a detailed assessment of trees for potential roost sites.
2.4 Evening Transect Surveys
Two experienced ECS surveyors5 walked two transect routes on 28 June 2013.
These are referred to as the north and south transects and are identified on Map
2 . Surveyors waited at the start of the transect route from sunset for 20 minutes
before commencing the walk. Each survey continued for 2 hours.
Both surveyors used a Petterson D240x time expansion detector and Edirol R09
recorder. Any time expansion calls needing subsequent analysis were assessed
2 Bat Surveys, Good Practice Guidelines, BCT (2012)
3 Bat Workers Manual (2004), Bat Mitigation Guidelines, (2004) both published by Natural England (formerly English
Nature)
4 IEEM Guidelines for Ecological Impact Assessment in the United Kingdom (June 2006).
5 Colleen Hope & Paul Hope. Colleen was accompanied by Simon Weymouth
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
5
using Batsound V3 software. Surveyors noted the species and activity of bats
they saw and heard.
2.5 Capture Surveys
Capture surveys were conducted on 16 May, 15 August and 2 September 2013
by the same surveyors6. Mist nets (2.6-12m x 2.6m Avinet bat nets) were set
across tracks and rides to capture commuting bats. A two bank harp trap (2.4 x
1.8 m Austbat) was used. An acoustic lure7 (Sussex AutoBat and/or Petterson
D1000x) was used an hour after sunset to attract bats into more cluttered areas
of vegetation.
Capture sites were focussed in two areas at the south and west of the site.
These included an area of former water meadows and woodland edge (capture
site 1) and an area of coniferous woodland (capture site 2). Nets were set in two
locations within each site. Between 8 & 9 nets and one harp trap were erected on
each survey evening. Surveys avoided the peak maternity season (June/July) to
avoid stressing pregnant or lactating bats. The two capture sites are shown on
Map 2.
Time of capture, species, sex, sexual status, weight and forearm measurements
were recorded for each bat. Tragus width and thumb length were recorded for
long-eared bats (an aid to the separation of brown and grey long-eared bat
species). All bats were released at the place of capture.
The use of mist nets, harp trap and acoustic lure were under licence WML CL19
& WML CL20 (levels 3 & 48) registration number CL502415.
Although the surveys focussed on capturing bats, surveyors also made informal
records of any bats heard on detectors. These results are shown on Maps 3a &
3b.
2.6 Survey Limitations and Precautionary Approach to Evaluation
Bat detectors have limited ranges. The calls from some species such as
pipistrelle, noctule Nyctalus noctula and serotine Eptesicus serotinus bats are
more likely to be heard than quieter species such as long-eared bats and those in
the genus myotis.
6 Accompanied by Simon Weymouth or Jay Doyle.
7 Playing pre-recorded or digitally processed bat social calls through ultrasound speakers to attract bats
towards nets/harp trap this permits the capture of bats using these methods up to three times in any one year per site without the
need for a specific project licence
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
6
The first capture evening was unseasonably cold which almost certainly
influenced the very low bat activity levels.
Bats move roosts and frequently alter foraging areas according to a number of
factors including time of year, weather, seasonal availability of food sources and
temperatures. Each survey should therefore be seen a ‘snap shot’ in time.
Signs of bat roosting are rarely present outside a tree roost entrance. Resources
did not permit a detailed assessment of trees for potential roost features.
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
7
Capture site 2
capture site 1
North Transect
South Transect
Map 2 To show key features of the site and locations of the transects and capture sites
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
8
3.0 Survey Results
3.1 Data Search
DERC held a number of records for the following species: common pipistrelle
Pipistrellus pipistrellus, soprano pipistrelle Pipistrellus pygmaeus, unidentified
pipistrelle Pipistrellus sp., long-eared bat Plecotus sp., brown long-eared bat
Plecotus auritus, noctule, serotine, Daubenton’s bat Myotis daubentonii,
unidienfied myotis sp. ‘myotis sp.’ and simply ‘unidentified bats’. Roost sites were
recorded for both common and soprano pipistrelle, brown long-eared bats. No
records were held for Bechstein’s bat and no roost records were held for serotine
bat.
3.2 Site Assessment
This is detailed in Section 4.2.
3.3 Evening Transect Surveys
3.3.1 28 June 2013 (sunset 21.24)
North Transect
Three species were encountered. Common and soprano pipistrelle bats were
heard commuting and foraging throughout the area with bats focusing along
tracks and rides. Four serotine bat passes were heard in two areas in the centre
and southern part of the transect.
South Transect
A greater diversity of species was encountered in the southern transect with six,
possibly seven species recorded. Common and soprano pipistrelle bats were
heard throughout the survey area with serotine bats focused more towards the
southern end. A noctule bat pass was also heard. Bats in the genus myotis
including one Daubenton’s Myotis daubentonii bat were heard at the far western
end of the transect near the Moors River and meadows. Two other ‘myotis’
recordings were made, one with a broadband call which may have been a
Natterer’s bat Myotis nattereri, the other with a narrowband call. A small number
of long-eared bat passes were also heard within the area.
Four small bats were seen at the beginning of the transect near the Matchams
Lane car park between 21.37 and 21.45. Their size suggested that the species
could only be pipistrelle, small myotis species or lesser horseshoe Rhinolphus
hipposideros bats. All of these species emerge relatively early in the evening.
The slow agile flight around low vegetation suggested that they were not
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
9
pipistrelle bats. Their early arrival suggests that they were roosting nearby.
Recordings could not be made as the bats were not echolocating.
3.4 Capture Surveys
3.4.1 16 May 2013
Seven mist nets and a harp trap were set at capture site 1 in the field east of the
river and the adjacent woodland edge. Bat activity levels were extremely low with
only a few common and soprano pipistrelle bat passes heard and no bats
captured. The temperatures dropped quickly which no doubt curtailed activity.
The following days were also cold after a brief warm spell in an otherwise wet
spring.
Table 1 Results of Capture Survey 16 May 2013
Mist net survey Hurn (16.05.2013)
Sunset: 20.51 Temp: 9.7-7.1 Cloud: 10 Wind: 0
End: 00.00 Surveyors: Colleen Hope, Paul Hope, Simon Weymouth
Time Species Sex Status F/Arm Weight (g) Thumb Tragus Other
no bats captured
During the surveys a noctule was seen and heard foraging above the field shortly
after sunset (21.10) suggesting it may have been roosting nearby. Between one
and two common and soprano pipistrelle bats foraged over the field and adjacent
woodland edge throughout the survey period.
3.4.2 15 August 2013
Eight mist nets and a harp trap were set near the Matcham’s Lane carpark
towards the south of the site at capture site 2. Two adjacent locations were
chosen which included the area where four non echolocating bats had been seen
during the transect survey. These bats were not encountered during this August
survey. Four species were captured including a juvenile noctule, two serotine,
two brown long-eared and one juvenile Natterer’s bats. One of the serotine as
well as both brown long-eared bats were parous (breeding) females. The
serotines were heard early in the evening suggesting they were roosting very
nearby, almost certainly in a building. Brown long-eared bats have a small range
normally within 1km of their roost sites and so this species is also likely to have
been roosting nearby.
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
10
A soprano pipistrelle bat was heard shortly after sunset at 20.20 which must have
been roosting nearby. Other than the species captured no other bats were heard.
Table 2 Results of Capture Survey 15 August 2013
Mist net survey Hurn (15.08.2013)
Sunset: 20.26 Temp: 19-17.8 Cloud: 0 Wind: 0
End: 23.30 Surveyors: Colleen Hope, Paul Hope, Simon Weymouth
Time Species Sex Status F/Arm Weight (g) Thumb Tragus Other
21.15 Nn m juvenile 52.4 28
22.30 Mn m adult 39 9
21.00 BLE f P 37.1 8 7.4 5.1
21.00 BLE f P 5.1 6.4
21.40 ES f P 51.3 22
21.40 ES m adult 54.5 20.5
Species code: Pa = Plecotus auritus, W/B = Myotis brandtii/ mystacinus, Pip = Pipistrellus sp,
Mn= Myotis nattereri, Mbec= Myotis Bechsteinii, ES=Eptesicus serotinus, Nn=Nyctalus noctula
Status code: p= parous, np= nulliparous, lac= lactating, a = Adult, j =juvenile
3.4.3 2 September 2013
Seven mist nets and a harp trap were set at capture site 1. Again activity levels
were low with only a few common and soprano pipistrelle bat passes heard. A
single adult male Bechstein’s bat was captured at 21.35 along the woodland edge
part of the site (see Photo 1).
The only other bats encountered throughout the evening were a single or small
number of common pipistrelle and one long-eared bat.
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
11
Table 3 Results of Capture Survey 2 September 2013
Mist net survey Hurn (02.09.2013)
Sunset: 19.50 Temp: 16.3-11.2 Cloud: 10 Wind: 0
End: 23.00 Surveyors:
Colleen Hope, Paul Hope, Jay Doyle
Time Species Sex Status F/Arm Weight (g)
Thumb Tragus Other
21.35 Mbec m adult 41.1 9.5
Species code: Pa = Plecotus auritus, W/B = Myotis brandtii/ mystacinus, Pip = Pipistrellus sp,
Mn= Myotis nattereri, Mbec= Myotis Bechsteinii, ES=Eptesicus serotinus, Nn=Nyctalus noctula
Status code: p= parous, np= nulliparous, lac= lactating, a = Adult, j =juvenile
Photo 1 Bechstein’s bat caught in September 2013.
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
12
4.0 Evaluation
4.1 Species Accounts
Table 4 below shows the status and distribution of the bat species encountered at
Hurn.
Table 4 To Show Status and Distribution of Bats in the UK (combined data from 9JNCC & 10IUCN).
Common name
Scientific name
Status JNCC Distribution JNCC
Status and population trend IUCN
Common Pipistrelle
Pipistrellus pipistrellus
common widespread LC stable
Soprano Pipistrelle
Pipistrellus pygmaeus
common widespread LC unknown
Brown Long eared bat
Plecotus auritus
common widespread LC stable
Daubenton’s bat
Myotis daubentonii
common widespread LC unknown
Natterer’s bat Myotis nattererri
frequent widespread LC stable
Noctule bat Nyctalus noctula
frequent frequent LC unknown
Serotine bat Eptesicus serotinus
frequent restricted LC unknown
Bechstein’s bat
Myotis bechsteinii
rare restricted NT decreasing
NT not threatened LC least concern
Annex 3 provides details of the basic ecology and habitat preferences of each of
the bat species recorded at Hurn.
Key to Maps 3a & 3b
Pp common pipistrelle
Ps soprano pipistrelle
ES serotine
Nn noctule
M myotis sp.
9 JNCC Habitat Management for Bats (2000)
10IUCN Red data list of threatened species (2008)
Md Daubenton’s
Mn Natterer’s
Unid unidentified bat (seen not
heard)
LE long eared
(f) foraging
(c) commuting
(s) social calling
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
13
Map 3a Results of North Transect 28/6/2013
Pp (c) 23.05
Ps (f) 23.07
Ps (f) 23.10
Pp (c) 22.43
2 x Pp (f) 22.34
Pp (c) 22.30
Ps (f) 22.16
ES 22.07 & 22.10 (c)
Ps (c) 22.02
2 x Pp (f) 21.54
Pp 21.50
Pp (c) 23.24 Ps (c) 23.47
ES 23.42 & 23.50 (c)
Date: 28/6/2013 Sunset time: 21.20
Surveyor/s: Paul Hope
start end
Start/end time 21.41 23.25
temperature 16.4C 16.4C
Cloud cover % 100 100
precipitation 0 0
wind 1 1
Species encountered:
Common pipistrelle, soprano pipistrelle,
serotine
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
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Map 3b Results of South Transect 28/6/2013
Pp 23.28 ES 23.30
ES 23.15
M/LE 23.16
4 x Unid 21.37-21.45 Nn 12.40 2 x Pp 21.40
ES 21.53 Pp 21.53
Pp 22.06 ES 22.08
Pp 22.24
Ps & Md 22.25
M (Mn?) 22.30
Pp (f) 22.37
Pp & Ps (f) 22.47 Pp & Ps (f) 22.50
2 x LE 22.40 Pp 22.40
M 22.52
Pp (f) 22.59
Date: 28/6/2013 Sunset time: 21.20
Surveyor/s: Colleen Hope/Simon
Weymouth
start end
Start/end time 21.40 23.40
temperature 17C 17C
Cloud cover % 100 100
precipitation 0 0
wind 0 0
Species encountered:
Common pipistrelle, soprano pipistrelle,
serotine, noctule, myotis sp,
Daubenton’s, long-eared, unidentified
bat sp.
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
15
4.2 General Site Evaluation
4.2.1 Overview of Habitats
The majority of the woodland in the site is coniferous plantation. Much of this is of
a similar age and there are large tracts of woodland where tree cover has
suppressed the shrub (field) and ground layers. This has resulted in a
homogenous habitat with limited species or structural diversity. In turn this limits
the diversity and numbers of invertebrates (upon which bats feed). The bat
species which are associated with open areas and edge habitats such as noctule,
serotine, Leisler’s Nyctalus leislerii and pipistrelle bats are more likely to utilise
the wide woodland rides and track as well as the woodland/heathland edge and
open habitats. Not surprisingly noctule, serotine and pipistrelle bats were all
common and reasonably widespread during the surveys.
Species such as long-eared, horseshoe bats and those in the genus myotis are
strongly associated with more dense woodland habitats where they are able to fly
amongst vegetation and in some cases ‘glean’ insects off the leaves. These
species thrive best in deciduous or mixed woodland particularly where a dense
and diverse understorey shrub layer is present. These habitats are lacking at
Hurn Forest; they are limited to the edges (particularly the western edge near the
Moors River) and a few wetter areas where streams run across the site. It is
probably no coincidence that the greatest diversity of bats captured and heard
during the surveys were in the areas with more diverse and dense shrub layer.
4.2.2 Foraging Habitats & Commuting Routes
There were no particularly well defined foraging areas identified during the
transects. Pipistrelle bats tended to utilise all suitable areas but were not found in
any areas in great densities. This probably reflects the homogeneous habitat
which does not provide focal sites for invertebrates.
Surprisingly the activity levels were also relatively low along the water’s edge.
This was evident not only during the transects but also during the capture
surveys.
Three to four serotine bats foraged north and south of the car park near
Matcham’s Lane for most of the survey period in August. Serotine bats were
heard on both transects. The early registrations for this species at capture site 1,
parous female caught in August and early registrations at the beginning of the
south transect strongly suggest that a maternity roost was present nearby,
possibly within 0.5km of Matcham’s car park. The activity and results of the
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
16
capture surveys suggest that there is also a maternity brown long-eared bat roost
nearby.
Pipistrelle and serotine bats commuted along woodland rides and tracks to some
extent but no clearly defined commuting routes were identified. This is probably a
reflection of the relatively small number of individual bats using the site. It should
also be noted that due to the quiet echolocation call of long-eared bats, their
commuting routes are harder to detect.
4.3 Assessment of Specific Habitat Types
4.3.1 Coniferous Woodland, Tracks & Rides
This is the dominant habitat within the site with Scott’s pine Pinus sylvestris &
Corsican pine Pinus nigra spp. the most commonly occurring species. As already
noted, its even age and structure result in limited foraging opportunities for bats
(see Photo 2). The tracks and rides are used by commuting pipistrelle and
serotine bats moving between foraging areas. They are also used by these ‘edge
habitat’ specialists as foraging sites in themselves. The most valuable tracks and
rides are those where light has reached and stimulated growth in the field layer
resulting in small shrubs and bushes which in turn support invertebrates (see
Photo 3 shows a more diverse edge to one of the rides (although this could be
improved further). Wetter areas also support more invertebrates (for example the
area immediately north of capture site 1).
More mature trees with signs of damage such as split or twisted trunks, limbs,
areas of rot or flaking bark provide potential roost sites for bats. Cavities
accessed by woodpeckers also provide roost sites for bats. All of these features
are limited in Hurn Forest.
Photograph 2: Homogenous stand with little structure along ride edges
Photograph 3: This ride has a more diverse edge with heather in the ground layer. It could
still be improved by selective thinning and possibly planting a shrub layer.
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
17
4.3.2 Deciduous woodland
This habitat is fairly limited in Hurn Forest. Although some planted mixed
woodland is present deciduous trees are mainly focused around the edges of the
coniferous woodland stands where trees have self sown (see Photo 4). These
trees still tend to be quite young and so although providing more structural
diversity there are few trees which are mature enough to support roost features.
Deciduous trees are also more prevalent along the sides of the watercourses
(e.g. silver birch Betula pendula and willow Salix sp.), some of which traverse the
site. These areas are potentially valuable bat foraging habitats in the context of
the more homogenous coniferous woodland.
4.3.3 Moors River & Adjacent Meadows
Although there is more structural diversity and there are wetter conditions along
this western perimeter (see Photo 5) the bat activity levels recorded during the
capture surveys and transects were surprisingly low. This may not be easily
explained (although one of the evenings was unseasonably cold). A large part of
the area to the west of the river corridor is open and dominated by the airport.
This lack of habitat may play a role in reducing activity in the area adjacent to it.
4.2.6 Heathland
Bats were recorded over the more open areas of heathland although this was
limited to pipistrelle and serotine bats. Few recordings were made of noctule bats
suggesting that a significant roost was not present nearby when the surveys were
conducted. Noctule bats favour more open areas for foraging and heathlands
provide good numbers of invertebrates.
Photograph 4: Woodland edge at capture site 1. Location of captured Bechstein’s bat
Photograph 5: Wetter habitat along field edge adjacent to Moors River at west of
site.
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
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Although the open nature of the heathland may not suit many species of bats it
may be an important source of invertebrate food which then migrates to the
woodland/healthland edges where it becomes more available.
Photograph 6: Heathland edge with open area in the background at Hurn Forest.
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5.0 Recommendations
5.1 Habitat Diversity
A long-term approach should be taken to diversify the age structure of some of
the trees by selective thinning/felling. Any new planting should be of deciduous
trees with the aim of increasing not only the diversity of the standard trees but
that of the under storey species.
Some individual trees may be selected for ring barking11. This eventually kills the
tree and provides standing deadwood habitats which encourage a diversity of
invertebrates (particularly beetles). It may also attract woodpeckers which create
holes which bats may use to access cavity roost sites. Flaking bark may also be
used by bats as a roost sites.
5.2 Tracks and Rides
Many of the tracks and rides are straight in plan view with abrupt vertical sides
showing little structural diversity. A varied ‘edge’ habitat is valuable for bats and
should be encouraged by creating meanders and bends in tracks and rides where
possible. This not only effectively increases the total length of the ‘edge habitat’
but prevents the track/ride acting as a wind tunnel. The structure of the tracks
and rides should be diversified by cutting back some of the edge trees and
encouraging or planting a field layer. This will encourage light and in turn more
vegetation and invertebrates and consequently food for bats.
11
Ring barked trees will eventually die and become unstable. They should be sited away from areas used by the public
Photograph 7: More varied structure to track edge (Fox Hunting Inclosure New Forest) with bracken and bramble grading into
holly and yew with standard trees (beech, pine and fir)
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5.3 Glades
Glades mimic areas around fallen veteran trees which in the past would have
been a natural dynamic of the woodland ecosystem. There are few glades within
any of the woodland blocks at Hurn Forest. Creating glades is another means of
increasing ‘edge habitat’ and species/structural diversity within woodland blocks.
A series of glades should be created in the homogenous woodland stands at
Hurn Forest. Ideally a woodland management plan should show how these will
eventually be linked to one another through subsequent selective thinning or
felling.
5.4 Water bodies
The wetter areas are valuable as they provide a greater diversity in both the
canopy and field layers. Many invertebrates also require water to breed. Any
opportunities to create new ponds should be taken. Networks of smaller ponds
are generally more valuable for species than single large bodies of open water.
5.5 Bat Boxes
Artificial roost sites can be created using bat boxes. Hurn Forest offers
comparatively few potential roost sites in trees and so these could offer a
valuable conservation method for habitat creation.
5.6 Community Involvement
Dorset Bat Group should be approached and their members encouraged to get
involved in the proposals. Most bat groups will be able to monitor sites e.g.
checking bat boxes and giving guided walks for the public. They rely on
volunteers and so a small contribution may be offered to cover expenses. Help
promoting public walks is also normally appreciated.
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Figure 1 To illustrate positive woodland management principals in coniferous woodland
(extract from JNCC, Habitat Management for Bats (2001)
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6.0 Conclusions
Seven bat species have been recorded within Hurn Forest during surveys in
2013. Most of these are common and nationally or locally widespread species
adapted for open or ‘edge’ habitats. The woodland habitats available within the
site are rather homogeneous in structure with low plant species diversity. A large
proportion of the site is open healthand. This results in a landscape which is
dominated by open and edge habitats. Potential roosting sites in trees on the site
are limited.
Notwithstanding this, a male Bechstein’s bat was captured along one of the more
diverse woodland edges and breeding brown long-eared (and serotine) bats are
apparently foraging in the more diverse woodland habitat towards the south of the
site.
There are good opportunities for improving the tree/shrub species and structural
diversity of the site without undertaking major woodland management works. By
altering the nature of rides and tracks and creating glades the number and
diversity of invertebrates will increase which will in turn benefit bats. Bat boxes
could also be erected to provide new roosting sites.
The recommendations made in this report will benefit a range of other species
such as birds, small mammals (including dormice if present), reptiles and
amphibians. The increased biodiversity and the more varied visual experience
will also enhance the site for the local community as well as visiting public. This
in turn could have the added advantage of reducing pressure from some of the
more sensitive sites such as the adjacent New Forest and Dorset Heaths.
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7.0 References
Bat Conservation Trust (2012) Bat Surveys-Good Practice Guidelines 2nd Ed
Bat Conservation Trust Species information leaflets – various (2005)
Boonman M Roost selection by noctules (Nyctalus noctula) and Daubenton’s bats
(Myotis daubentonii) Journal of Zoology (2000)
Davidson-Watts I & Jones G Differences in foraging behaviour between
Pipistrellus pipistrellus (Schreber, 1977) and Pipistrellus pygmaeus (Leach, 1825)
(Journal of Zoology (2005)
Davidson-Watts I, Walls S & Jones G Differences in habitat selection by
Pipistrellus pipistrellus & Pipistrellus pygmaeus identifies distinct conservation
needs for cryptic species Biological Conservation (2006)
Fitzimmon P, Hill D & Greenaway F Patterns of habitat use by female
Bechstein’s bats (Myotis bechsteinii) from a maternity colony in a British
woodland (2002)
Gloor S, Stutz Hans-Peter B, & Zisinler V Nutritional habitats of the noctule bat
Nyctalus noctula (Schreber 1774) in Switzerland Myotis (1995)
Hope PR & Jones G Warming up for dinner: torpor and arousal in hibernating
Natterer’s bat (Myotis naterreri) studied by radio telemetry. Journal of
Comparative Physiology (2012)
The Conservation (Natural Habitats &c.) (England & Wales) Regulations 2010 (as
amended).
Institute for Ecology and Environmental Management (IEEM). (2006). Guidelines
for Ecological Impact Assessment in the United Kingdom. Approved Version 26
June 2006. IEEM Document.
JNCC (2000) Habitat Management for Bats
National Planning Policy Framework (April 2012) Department for Communities &
Local Government
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Natural England Bat Mitigation Guidelines (2004)
Natural England Bat Workers Manual, 3rd Ed (2004)
Natural England website: http://www.natural-
england.org.uk/regions/east_of_england/ourwork/standingadvice/protectedspecie
s/bats.aspx
Natural England (2009) WML-G12-EPS Mitigation Licensing-How to Get a
Licence – Version 5
ODPM (2006) Planning for Biodiversity and Geological Conservation: A Guide to
Good Practice Office of the Deputy Prime Minister
Planning Policy Statement 9: Biodiversity and Geological Conservation Office of
the Deputy Prime Minister. June 2009 ODPM (2005)
Racey P & Swift S Feeding ecology of Pipistrelleus pipistrellus during pregnancy
and lactation .I. foraging bechaviour Journal of Animal Ecology (1985)
Robinson M F & Stebbings RE Home range and habitat use by the serotine bat,
Eptesicus serotinus, in England J Zoology (1997)
Robinson M F & Stebbings RE Activity of the serotine bat, Eptesicus serotinus, in
England Myotis (1997)
Siemens B & Swift S Differences in sensory ecology contribute to resource
partitioning in the bats Myotis bechsteinii and Myotis naterreri (Chiroptera:
Vespertilionidae) Behavioural Ecology & Sociobiology (2005)
Yalden D The history of British Mammals Poyser Natural History (1999)
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Annexes
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Annex 1 Legislation & Policy
Legislation
The two key pieces of legislation affording protection to bats and their roosting
sites are the Conservation of Habitats and Species Regulations 2010 (as
amended)12 and the Wildlife & Countryside Act 1981 (amended 2007).
Under the Conservation of Habitats and Species Regulations 2010 (as amended)
it is an offence to deliberately kill, capture or injure a European protected species,
or to damage or destroy the breeding site or resting place of such an animal.
Disturbance of a European protected species is also an offence if done in such a
manner as to be likely to significantly to affect:
(a) the ability of an EPS to survive, breed, or reproduce, or to rear or nurture
young, to hibernate or migrate; or
(b) the local distribution of that species.
All species of bat in the UK are European protected species (EPS) and thus
protected by this legislation. Because bats return to roost sites on a regular basis,
the roost site is considered to be legally protected even when the bat is not
present. If any activities relating to development which could result in any of the
offences above are undertaken it is necessary to obtain a licence from Natural
England (formerly issued by Department for Environment, Food and Rural Affairs,
DEFRA). In order for a licence to be granted the following conditions must be
satisfied:
� The proposal must be necessary ‘to preserve public health or
public safety or other imperative reasons of overriding public
interest including those of a social or economic nature and
beneficial consequences of primary importance for the
environment’;
� ‘There is no satisfactory alternative’;
� The proposals ‘will not be detrimental to the maintenance of
the population of the species concerned at a favourable
conservation status in their natural range’.
The Wildlife & Countryside Act (WCA) 1981 was amended by the recent changes
to the Conservation (Natural Habitats &c) Regulations 1994 (amended 2010).
The WCA also makes it an offence to intentionally or recklessly disturb bats to
obstruct access to roost sites, and to sell or advertise bats for trade. The
12
(referred to as the ‘Habitats Regulations’ and formerly the Conservation (Natural Habitats &c) Regulations 2010 (as amended), (England & Wales, as amended),
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Countryside & Rights of Way Act 2000 (CROW) strengthened the WCA by adding
the word ‘recklessly’ to these offences.
The Natural Environment & Communities Act (NERC) 2006 states (s40) that
‘Every public body must, in exercising its functions, have regard, so far as is
consistent with the proper exercise of those functions, to the purpose of
conserving biodiversity.’
Section 40(3) also states that
‘conserving biodiversity includes, in relation to a living organism or type of habitat,
restoring or enhancing a population or habitat.’
Priority species are listed in s41 of the NERC Act. These include the
following bat species: soprano pipistrelle Pipistrellus pygmaeus, brown long-
eared bat Plecotus auritus, Bechstein’s bat Myotis bechsteinii, noctule
Nyctalus noctula, barbastelle bat Barbastella barbastellus and greater and
lesser horseshoe bats Rhinolophus ferrumequinum/ R. hipposideros.
Policy
The National Planning Policy Framework (NPPF) became effective on 27 April
2012. This sets out the Government’s planning policies for England & Wales and
how they should be applied. Although policies in local plans (and the London
Plan) should not be considered out-of–date simply because they were adopted
prior to the publication of the NPPF, the NPPF policies are material
considerations which local planning authorities should take into account. The
NPPF must also be taken into account during the preparation of local and
neighbourhood plans.
The NPPF effectively made Planning Policy Statement 9; Biodiversity and
Geological Conservation (PPS9) redundant. Circular 06/0513 remains an active
document to be used in conjunction with the NPPF rather than PPS914 15.
The main thrust of the NPPF is that is has a clear:
13
ODPM Circular 06/2005: Biodiversity and Geological conservation-Statutory Obligations and Their Impact within the Planning System (Circular 06/05). 14
The Government will “now embark on a new exercise to consider what underpinning guidance continues to be needed”. A timetable for this process has not as yet been set (May 2012) however “until such time as the guidance review is complete, the existing guidance where relevant can still b used.” 15
However, for 12 months from the day of the publication of the NPPF decision makers may continue to give full weight to the relevant polices adopted since 2004 (e.g. PPS9 & PDPM 06/05) even if there is a limited degree of conflict that the NPPF.
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“presumption in favour of sustainable development, which should
be seen as a golden thread running through both plan-making
and decision-taking.” (Para 4)
With regard to protecting the natural environment, planning should still enhance
the natural environment and where possible provide net gains for biodiversity16.
Para 118 states that:
“Opportunities to incorporate biodiversity in and around
developments should be encouraged”
and that planning policies should
“ promote the preservation, restoration and re-creation of priority
habitats, ecological networks and the protection and recovery of
priority species populations, linked to national and local targets,
and identify suitable indicators for monitoring biodiversity in the
plan” (Para 117).
The NPPF states that with regard to conserving the natural environment the
planning system should contribute to and enhance the natural and local
environment by:
• protecting and enhancing valued landscapes, geological
conservation interests and soils;
• recognising the wider benefits of the ecosystem services;
• minimising the impact on biodiversity and providing net gains in
biodiversity where possible, contributing to the Government’s
commitment to halt the overall decline in biodiversity, including by
establishing coherent ecological networks that are more resilient to
current and future pressures;
• preventing both new and existing development from contributing
to or being put at unacceptable risk from, or being adversely
affected by unacceptable levels of soil, air, water or noise pollution
or land instability; and
• remediating and mitigating despoiled, degraded, derelict,
contaminated and sustainable land, where appropriate.” (Para
109)
Section 11 of the NPPF (Conserving and enhancing the natural environment)
also identifies how planning policies should plan for biodiversity at a landscape
scale, and take an active role in promoting and enhancing (and re-creating)
16
The NPPF also emphasises the importance of ecosystem services and soils.
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priority habitats and ecological networks as well as protecting and supporting the
recovery of priority species populations.
Species and habitats listed in UK BAPs were identified as priority consideration
for biodiversity conservation by public authorities through Sections 40-42 of the
NERC Act 2006) in England and Wales. ‘Biodiversity 2020: A Strategy for
England’s Wildlife and Ecosystem Services (2011)’ replaced the previous
‘England Biodiversity Strategy’. The ‘UK BAP’ was also replaced with the ‘UK
Post-2010 Biodiversity Framework (2012)’. Biodiversity issues are now devolved.
What are still sometimes referred to as ‘BAP species’ and ‘BAP habitats’ are now
referred to as ‘Species and Habitats of Principal Importance for Conservation in
England’, (or simply ‘Priority Species’ and ‘Priority Habitats’). This list of habitats
and species remains unchanged and is still derived from S41 of the NERC Act
(2006). Consequently these species and habitats are a material consideration for
planning purposes.
Priority species listed on S41 of the NERC Act include the following bats:
soprano pipistrelle Pipistrellus pygmaeus, brown long-eared bat Plecotus auritus,
Bechstein’s bat Myotis bechsteinii, noctule Nyctalus noctula, barbastelle bat
Barbastella barbastellus and greater and lesser horseshoe bats Rhinolophus
ferrumequinum/ R. hipposideros.
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Annex 2 Surveyor Experience
Colleen Hope (nee Mainstone), BSc, MCIEEM
Director, Ecological Consultancy Services Ltd.
I am joint Director of Ecological Consultancy Services Ltd (ECS), a locally based
ecological consultancy which I established in 2008. Prior to this I was employed
in a senior role at a consultancy based in Winchester for six years.
ECS employs two permanent staff who undertake surveys for a wide range of
protected species including reptiles, great crested newts, dormice, otters, water
voles, bat and barn owls. ECS specialises in surveying and assessing sites for
bats.
ECS has a wide client base including local authorities, the Environment Agency,
Forestry Commission, National Trust and large, small and medium sized planning
consultancies. ECS also provides specialist bat survey services to other
ecological consultancies mainly with regard to Environmental Impact
Assessments (EIA).
I hold Natural England survey licences (levels 3 & 4) and am licenced to train
individuals to licence level. I have successfully obtained over 55 DEFRA/Natural
England EPS (bat) development licences for a range of sites including modern
and historic buildings, barns, trees, large scale new town developments, wind
farms and road schemes. I am a Registered Ecological Consultant under Natural
England’s Trial Low Impact Licence scheme.
Over the last 12 years I have managed a number of county and borough wide bat
surveys including a capture, ringing and radio tracking study into the distribution
of Bechstein’s and barbastelle bats in the New Forest, Hampshire. Bat survey
work has taken me overseas to India, Burma (Myanmar) and Vietnam.
Dr Paul Hope, BSc (Hons), MCIEEM
Director, Ecological Consultancy Services Ltd.
Paul is also joint Director of ECS and based in Romsey, Hampshire. He
undertakes site appraisals for a range of species including reptiles, badgers,
watervoles, dormice and species and specialises in surveying for bats.
Paul has held Natural England bat survey licences for over 12 years and has 8
years experience undertaking a range of surveys for both bats and reptiles. He is
licenced trainer for Natural England (Conservation licences) and also trains
consultants for bat survey licences.
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Paul is just completed a part time PhD at the University of Bristol studying the
hibernation ecology of British bats. He has extensive experience in the collection
and analysis of field data using of a range of monitoring devices including bat
detectors (time expansion, frequency division and heterodyne), infrared motion
sensors and radio telemetry equipment for receiving and data logging.
During the process of surveying for environmental impact assessments both Paul
and I have undertaken radio tracking and ringing studies of seven bat species.
We each have over 1000 hours radio tracking experience radio tracking a range
of bat species in relation to impact assessments for development and providing
information for bat conservation.
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Annex 3 Status & Distribution of Species Encountered
Common & Soprano pipistrelle
Common and soprano pipistrelle bats are common and widespread throughout
the UK and most of Europe (BCT, 2003). They are morphologically cryptic
species, however in most cases they can be identified by their echolocation calls
at 46 & 55 KHz respectively. Racey & Swift (1985) radio tracked pregnant and
lactating common pipistrelle bats in a lowland agricultural area with extensive
foraging resources and by contrast an upland area with less available resources.
The mean distance flown by pregnant bats in the agricultural landscape was
1.8km between roost sites and foraging areas with a maximum distance of 5.1km.
Distances were reduced to 1.3 and 3.7km respectively during the lactation period.
Distances travelled in the upland area averaged 1km with a maximum of 2.5km in
both the pregnancy and lactation periods.
Racey & Swift observed that bats moved along a regular route and were sighted
at the same place and the same time on successive nights. Individual foraging
beats were rarely defended with large numbers of bat foraging in small areas
where insect densities were high. Foraging beats were usually over water, along
hedgerows or around individual trees.
Davidson Watts, Walls & Jones, (2006) demonstrated different habitat
preferences between the two species. Soprano pipistrelle bats favoured riparian
habitats over all other potential habitats and foraged mainly on flies with an
aquatic larval stage whilst common pipistrelles were more generalist foragers
including a wider range of dipteran families in their diet and foraging more widely.
Compositional analysis was used to show and rank the preferred habitat used by
each species (>>> reflects a significant difference between adjacent habitats).
Common pipistrelle favoured deciduous woodland>grassland>riparian>suburban
mixed woodland>arable>>conifer woodland.
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Soprano pipistrelle favoured riparian woodland>riparian grassland>>>deciduous
woodland>suburban>>>mixed woodland>conifer>arable
Davidson Watts & Jones (2005) found that common pipistrelle bats made more
flights to a greater number of foraging areas that soprano pipistrelle bats however
the distances travelled by common pipistrelle bats was shorter. The larger
distances flown by soprano pipistrelle bats probably reflected its selectivity in
foraging areas techniques.
The average colony size of common pipistrelle bats in the UK is estimated to be
between 68 bats. The average colony size of soprano pipistrelle bat in the UK is
estimated to be between 288 (BCT, 2005).
Noctule bat
The status and distribution of noctule bats in the UK is described as ‘frequent’
occurring throughout England and Wales and southern Scotland although they
are scarce in intensively agricultural areas. Noctule bats are a one of the largest
species in the UK. Their narrow wings allow them to fly fast (30mph/50kph) and
cover large distances in a short period of time; they may commute between 6km
and 10km between roost and foraging sites (BCT, 2005). They are one of the
first species to emerge and can be seen in almost daylight; they often forage for
the first two hours after dusk before returning to the roost and foraging again for
approximately 30 minutes at dawn. Their favoured habitats are deciduous
woodland, parkland, pasture, water bodies and forest edges (BCT, 2005).
Noctule bats forage on insect swarms in summer often forming large groups of
bats that employ a filter feeding technique. Insects remains found in droppings of
noctule bats in a study in Switzerland revealed trichoptera and diptera families
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many of which have a larval stage dependent upon water. In spring and autumn
noctule forage on larger beetles (Gloor, Stutz & Ziswiler, 1995). Noctule bats are
often seen foraging over water bodies and are confident flying away from
vegetation.
Roost sites are almost exclusively in trees in the UK although buildings are used
on the continent. Boonman (2000) studied 81 noctule summer roosts in the
Netherlands and found a strong holes but to a lesser extent). Roost sites were
close to woodland edges probably to reduce commuting journeys to foraging sites
but also for thermoregulatory reasons.
In April, mixed sex roosts are evident but males form solitary roosts in
midsummer. In autumn males call loudly from mating roost sites. Females will
move maternity roosts frequently even carrying young with them.
Noctule bats are a migratory species in Europe and Russia although solitary,
mixed sex hibernation roosts are known which include individuals from several
different summer colonies (Petit & Meyer, 2000 cited in Harris & Yalden (2008).
The average colony size of noctule bat in the UK is estimated to be between 15-
50 with occasionally up to 100+ (BCT, 2005).
Serotine bat
Serotine bats are frequent and restricted in the UK, mainly south below a line
from the Wash. They may be moving their range northwards but there are
reported declines of this species from south eastern counties such as Sussex and
Hampshire; recent concern for their status has led to a species conservation
group forming in southeast England. A biodiversity action plan was drawn up for
serotine bats in neighbouring Hampshire in 2002 after a county wide review of all
known records by Hampshire Bat Group suggested that numbers had declined
(Mainstone unpub.)
Serotine bats are one of the largest species of bat in the UK. They have broad
wings, a highly manoeuvrable flight and forage in ‘edge’ habitats; they are equally
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happy foraging over relatively open areas of grassland and can often be seen
foraging around streetlamps on insects attracted to these areas. Favoured
habitats include parkland, leafy suburban areas, pasture and open woodland
areas (BCT 2008). Robinson & Stebbings studied the foraging behaviour of
serotine bats in 1989 and recorded all foraging sites to be within 300m of pasture
or woodland which they considered to be vital habitat for this species survival.
Bats spent 83% of their time foraging over pasture and woodland (43.6% over
woodland and 39.6% over pasture). Serotine bats feed mainly on moths and flies
in springtime favouring dung beetles and chafers in summer. Robinson &
Stebbings (1997) recorded bats visiting between 0-10 feeding sites per night
when bats commuted along hedgerows, tree lines and over pastures. In a study
by Catto (1996) bats travelled an average 6.5km between foraging sites using up
to 5 sites per night with higher foraging ranges in predominantly arable areas.
Harris & Yalden (2008) cite serotine bats flying close to trees, particularly the
canopy and along hedgerows, street lights and occasionally feeding well within
beech woods. They describe a slow and manoeuvrable flight often close the
ground or up to 10m with sudden steep dives.
Serotine bats emerge early from the roost sites, between 10-40 minutes of dusk
(BCT, 2005); Robinson & Stebbings (1997) recorded a mean time of emergence
as 22.1 minutes after sunset. Bats return to the roost to feed their young
frequently during the lactation period. Robinson & Stebbings (1997) radio tracked
serotine bats and recorded a single bout of feeding for about 90 minutes in May
and June (early gestation) with a bimodal pattern in July and August (post
lactation period); 140 minutes foraging was typical. Bats returned to the roost
during the lactation period but after lactation remained in temporary night roosts.
From early September and October activity was confined to a single short period
after dusk. Adults entered hibernation early for most bats in September or
October followed slightly later by juveniles.
Roost sites are almost exclusively in buildings with older buildings favoured and
access points often at gable eaves (BCT, 2005). Little is known about the mating
strategy or hibernation of this species.
The average colony size of serotine bat in the UK is estimated to be between 15-
30 (BCT, 2005).
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
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36
Daubenton’s bat
Daubenton’s are a medium sized bat in the genus myotis which roosts in trees,
buildings and other structures (often bridges). Strongly favouring humid sites,
they have a strong association with water bodies and can be seen foraging over
open stretches of water (BCT 2008). Daubenton’s bats forage manly with 6km
of the roost site (occasionally up to 10km). They forage in woodland but
frequently over water where they trawl emerging insects from the water surface
with their large feet. Their diet consists largely of chironomid midges, mayflies
and caddisflies (BCT, 2008).
Male and non breeding female bats may congregate in summer communal roosts
or occasionally within maternity roosts. Sexual segregation of roosts sites has
been shown in studies of Daubenton’s bats on Yorkshire Rivers. While studying
27 Daubenton’s summer roosts in the Netherlands Boonman (2000) found a
strong preference for roost sites just within woodland edges with oak trees
preferred over beech. All roost locations were in cavities accessed by rot or
woodpecker holes.
The average colony size of Daubenton’s bat in the UK is estimated to be between
20-50 with occasionally up to 200+ (BCT, 2008).
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
37
Natterer’s bat
Natterer’s bats are frequent and widespread throughout the UK. The UK may be
internationally important for this species (BCT, 2003). Natterer’s bat is a medium
sized species within the genus myotis. It forages using low searching flight,
hovering, capturing insects in the tail membrane and consuming prey at feeding
perches or on the wing (Swift & Racey, 2002). Swift & Racey studied the foraging
strategy of this species and found that their main prey items were medium sized
arthropods particularly dung beetles, spiders, harvestmen and beetles with a few
moths. They also noted that Natterer’s and brown long-eared bats utilised similar
habitats but long-eared bats used passive listening as a foraging technique and
favoured ‘noisy’ insects whilst Natterer’s were able to exploit quiet insects by
using echolocation as the primary foraging technique. They also recorded
Natterer’s bats landing and pursuing prey on the ground.
In a foraging study of this species, Swift & Racey found Natterer’s bats moved
roosts every few days, often using a number of roosting locations in any site.
67% of roost sites were in trees (mostly oak or ash) with roof mortice joints in
attics and barns, soffits, crevices in walls, apices of eaves and a modern cavity
wall also used. Foraging is mainly concentrated in core areas of up to 2km² with
roost density ranging from 7-15 per km². Swift & Racey concluded that the bats
required access to a large number of roosts with a range of temperatures
dependant on their reproductive state and energy requirements. Bats showed
high fidelity to roost sites in successive years.
Hope & Jones (2012) found that Natterer’s bat frequently arose from torpor during
hibernation period and that these arousals were timed with sunset. They
suggested that Natterer’s bat may take advantage of mild winter evenings to
forage.
The median emergence time after sunset for Natterer’s bat was 75 minutes in a
study by Jones & Rydell (1994), making them one of latest emerging species in
the UK. Like long-eared bats they appear to be light-shy and may be active and
flying inside a building roost for some time before emergence. When emerging
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
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Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
38
from trees they may remain around the roost tree or adjacent trees for some time
before venturing away from cover. Natterer’s bats roost in crevices in trees such
as splits and tears and in buildings using locations such as mortice holes and
splits in timbers and crevices between bricks or stonework or beneath tiles.
There may be very little evidence of roosting outside the roost site; which
combined with their late emergence in poor light their roost sites contributes to
the species frequently being overlooked.
The average colony size of the Natterer’s bat in the UK is estimated to be
between 20-100 with occasionally up to 100+ (BCT, 2005).
Bechstein’s bat
Bechstein’s bat is one of Europe’s rarest bats and is confined in the UK mainly to
the south of the country. It is widespread within its range which includes the
Iberian Peninsula to the Ukraine and is at the northern border of its range in the
UK. Although it is widespread in Europe, its populations are believed to be low
(although local densities can be high). Its population has declined throughout its
range and it is ‘vulnerable’ (IUCN, 2001). It was probably common in Neolithic
times when its woodland habitat was very much more widespread as fossil
remains in Grimes Graves in Norfolk suggest (Yalden, 1999).
Recent studies suggest that an ideal Bechstein’s wood is deciduous, uneven in
age, 40-50 hectares in extent and to be semi natural or ancient in origin with a
dense understorey and a watercourse. Bechstein’s colonies may also survive in
oak and mixed hardwood forestry plantations provided there are adequate
suitable roost sites and a dense understorey.
In the UK Bechstein’s bats show a significant preference for trees as roost sites,
although bat boxes have successfully attracted bats and there are a handful of
records of roosts in buildings. Roost sites are most commonly found in cavities
excavated by woodpeckers in oak Quercus sp. or beech Fagus sylvatica (or ash
Fraxinus excelsior on Isle of Wight).
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
39
Group sizes within maternity roost sites vary as individuals regularly split off and
regroup within the colony range. This constant ‘fission fusion’ behaviour makes
population estimates difficult but average colony size is believed to be 15-40
animals, maximum 80 (Kerth & Konig, 1999, Germany). The average roost size
of five maternity colonies studied in the New Forest between 2005-2013 has been
between 30-40 bats (pers obs.)
The core foraging area of individual female Bechstein’s bats is smaller than for
most other species of bat. The maximum distance between foraging area and the
main roost site of females during the West Sussex radio tracking study in this
study was 1.4km (Fitzimmons, Hill & Greenaway, 2002). The main prey items
of Bechstein’s bats are moths, flies, harvestmen, earwigs and crickets (Siemen’s
& Swift, 2005)
A UK population estimate of 1500 is quoted in Harris & Yalden (2008) but the
authors note that populations are difficult to assess because of the small number
of known colonies; they state that the population could be as great as 20,000 –
25,000.
Brown long-eared bat
Long-eared bats are a medium sized species differing from most Palaearctic
species in having broad wing and long ears. These morphological characteristics
allow them to hover in flight, listen for and glean insects (mainly moths) from
surfaces (Entwistle, Racey & Speakman, 1996). These features do however
result in a slow flight which makes them vulnerable to predation and this may be
why they are wary of flying across open spaces. Long-eared bats emerge from
roost sites later than most species when light levels are lower.
Long-eared bats appear to be light-shy and may be active and flying inside a
building roost for some time before emergence. When emerging from trees they
may remain around the roost tree or adjacent trees for some time before
venturing away from cover. Their echolocation call is relatively quiet and as a
Bat Surveys of Hurn Forest, Dorset January 2014 (final report)
___________________________________________________________________________________
Colleen Hope (nee Mainstone), MCIEEM Ecological Consultancy Services Ltd (ECS)
colleen@econserve.co.uk www.econserve.co.uk tel 01794 524232 (m) 07719 170200 copyright ECS
40
result they are not readily heard on a bat detector, making them prone to under
recording in field surveys.
Brown long-eared bats were the subject of a study in NE Scotland by Entwistle,
Racey and Speakman who radio tracked bats from 6 roosts in 1991 & 1992 in
order to investigate their foraging behaviour and preferences. During this study
bats emerged approximately 55 minutes after dusk and remained active
throughout the night. Individuals used a series of foraging sites to which they
returned regularly, sometimes these were shared with other roost mates. They
foraged exclusively in woodland and around individual trees with a strong
preference for deciduous woodland over coniferous woodland; the authors
suggested that this related to the higher productivity of deciduous woodlands for
Lepidoptera (moths) the principal prey item of this species. Where coniferous
woodland was used, bats remained round the edges not venturing into the centre
of these woodlands.
In this study long-eared bats were observed commuting along hedge lines, tree
and fence lines and along woodland corridors and overgrown banks; males
travelled further than females between roosting sites and foraging areas. Bats
travelled up to 2.8 km maximum distance from roost sites to forage but spent
most of their time within 0.5km of the roost sites and used between 1-9 foraging
sites per night (median 3) with bats returning to the same foraging site up to 5
times per night.
Bats used a limited number of sites in any one location at any one time of the
year and there was high night to night predictability in foraging sites. 77% of sites
were used by the same individual on more than one night. During periods of rain
bats hung up and became inactive but there was no evidence of reduced activity
in lower temperatures (<7C) with bats active at temperatures as low as 3.5C.
The average colony size of the brown long-eared bat in the UK is estimated to be
between 10-20 with occasionally up to 50 (BCT, 2005).
Recommended