KILDARE BAT GROUP &
BAT CONSERVATION IRELAND
Tidy Towns:
Leixlip, Co. Kildare
Bat Survey
Surveying completed by Kildare Bat Group
Report by Dr Tina Aughney
2014
Report prepared for:
Leixlip Tidy Towns Group
ULEX
BAT CONSERVATION IRELAND
HOUSE, DRUMHEEL, LISDUFF, VIRGINIA, COUNTY CAVAN
SUMMARY
Site:
Leixlip, County Kildare
Development:
General wildlife enhancement under Tidy Towns
Grid reference:
Various – see report for details
Survey by:
Kildare Bat Group
Bat species recorded:
common pipistrelle, Leisler’s bat, Daubenton’s bat,,
soprano pipistrelle and Myotis spp.
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1.
Introduction
The Kildare Bat Group and Bat Conservation Ireland provided bat surveying services in
order to gather data on the bat usage and bat potential of a selection of villages and towns in
County Kildare. This information is to be used to determine wildlife enhancement works for
bats under the Tidy Towns application.
Such surveying was completed due to the fact that bats are protected species under the
Wildlife Act (1976) and Wildlife [Amendment] Act (2000). Across Europe, they are further
protected under the Convention on the Conservation of European Wildlife and Natural
Habitats (Bern Convention 1982), which, in relation to bats, exists to conserve all species
and their habitats. The Convention on the Conservation of Migratory Species of Wild
Animals (Bonn Convention 1979, enacted 1983) was instigated to protect migrant species
across all European boundaries. The Irish government has ratified both these conventions.
Also, the EC Directive on The Conservation of Natural habitats and of Wild Fauna and Flora
(Habitats Directive 1992), seeks to protect rare species, including bats, and their habitats
and requires that appropriate monitoring of populations be undertaken. All bat species are
protected under Annex IV of the EU Habitats Directive, while the lesser horseshoe bat is
listed under Annex II. Member states are required to designate Special Areas of
Conservation for all species listed under Annex II in order to protect them.
1.1
Site description
Leixlip is a town in north County Kildare and is located on the confluence of the River Liffey
and Rye water. The population of the town is around 15,000 and it is the fourth largest town
in the county. Notable areas of habitats include the rivers mentioned above, the Royal
Canal, St. Catherine’s Park and Louisa Valley while the grounds of Castletown House are
located south-west of the town.
1.1
Bat records for County Kildare
There are 416 bat records for the county, 19 of which refer to roost sites. The bat species
recorded in the county are as follows: whiskered bat Myotis mystacinus (1 record); Natterer’s
bat M. nattereri (10 records); Daubenton’s bat M. daubentonii (67 records); common
pipistrelle Pipistrellus pipistrellus (131 records); soprano pipistrelle P. pygmaeus (85
records); Leisler’s bat Nyctalus leisleri (69 records), brown long-eared bat Plecotus auritus
(21 records) and Nathusius’ pipistrelle Pipistrellus nathusii (1 record). Please see Map 1 – 10
for a display of these records.
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Bat Survey Report
Map 1: Location of Leixlip Town, County Kildare.
Map 2: Location of bat roosts and bat detector records held on the BCIreland database (2000-2012 dataset).
Map 3: Location of brown long-eared bat records held on the BCIreland database (2000-2012 dataset).
Map 4: Location of common pipistrelle records held on the BCIreland database (2000-2012 dataset).
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Map 5: Location of Daubenton’s bat records held on the BCIreland database (2000-2012 dataset).
Map 6: Location of Leisler’s bat records held on the BCIreland database (2000-2012 dataset).
Map 7: Location of Nathusius’ pipistrelle records held on the BCIreland database (2000-2012 dataset).
Map 8: Location of Natterer’s bat records held on the BCIreland database (2000-2012 dataset).
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Map 9: Location of soprao pipistrelle records held on the BCIreland database (2000-2012 dataset).
Map 10: Location of whiskered bat records held on the BCIreland database (2000-2012 dataset).
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2.
Survey Methodology
This report presents the results of site visits by the Kildare Bat Group carried out on 21/5/14,
28/5/14 and 9/7/14 during which a bat surveys were completed at three locations: Louisa
Bridge, Leixlip Town/Rye Water/Scouts Den and Wonderful Barn respectively. A daytime
survey was undertaken to identify any Potential Bat Roosts (PBRs) in the structures.
Evidence of bats is in the form of actual bats (visible or audible), bat droppings, urine
staining, grease marks (oily secretions from glands present on stonework) and claw marks.
In addition, the presence of bat fly pupae (bat parasite) also indicates that bat usage of a
crevice has occurred in the past.
A dusk survey was completed and this involved a walkabout survey of the town environs
using heterodyne bat detectors. Dusk survey was completed from 20 minutes after sunset
for approximately two hours.
2.1
Survey Constraints
This survey was undertaken inside the preferred summer months as specified in bat survey
guidelines. There were no survey constraints with regards to the current structure
inspections and bat surveys.
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3. Results
3.1 Walkabout Bat Detector Survey
Members of the Kildare Bat Group completed a bat survey of the town on the 21/5/14,
28/5/14 and 9/7/14. The bat species encountered were recorded along with the grid
reference. This is detailed in Table 1.
Survey Date: 21/5/14 Rye Water & Royal Canal
Easting
Northing
Species
Details
288638
239320
Common pipistrelle
Adjacent to aquaduct – Rye Water & Royal
Canal
Leisler’s bat
Soprano pipistrelle
Good foraging area.
pipistrelle nearby.
Potential
299555
237942
Leisler’s bat
Hawthorn treeline along canal
299595
236942
Common pipistrelle
Canal adjacent to tall building
soprano
Leisler’s bat
299629
236976
Leisler’s bat
Daubenton’s bat
Otherside of tall building, potential Leisler’s
roost in area.
Adjacent to canal.
296636
236945
Daubenton’s bat
Adjacent to canal.
299569
236785
Daubenton’s bat
Adjacent to canal.
Survey Date: 28/5/14 Wonderful Barn, Castletown House (Weather conditions: 13 oC,
light breeze, cloudy and mild)
Easting
Northing
Species
Details
289518
235636
Common pipistrelle
Wild meadow, old treeline behind Dove Côte
(Lux reading – 4)
Leisler’s bat
299256
235386
Leisler’s bat
Courtyard
299198
235393
Common pipistrelle
Low hedges adjacent to house
Potential roost present
299217
235384
Leisler’s bat
Orchard
299080
235376
Soprano pipistrelle
Field in front of house
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Survey Date: 9/7/14 Leixlip Town (Weather conditions: 11 oC, light breeze, cloudy and
mild)
Easting
Northing
Species
Details
300463
235832
Common pipistrelle
Adjacent to the Rye Water (Lux reading – 14)
Soprano pipistrelle
300499
235788
Common pipistrelle
Adjacent to church
300506
235782
Soprano pipistrelle
Low hedges adjacent to house
Potential roost present
300556
235782
Daubenton’s bat
Adjacent to water, steep embankment
300614
235817
Daubenton’s bat
Adjacent to water, to rear of car park
Leisler’s bat
300686
235834
Daubenton’s bat
Adjacent to water, footbridge over River Liffey
Leisler’s bat
COMMENTARY
At least four species of bat were recorded during this brief survey. Daubenton’s bats were
only recorded in areas where there was water present. The remaining species (common
pipistrelle, soprano pipistrelle and Leisler’s bats) are common Irish bat species. There is
likely to be many roosting sites within the town and adjacent habitats. The Louisa Valley and
St. Catherine’s Park provides an essential wooded area connecting bother the River Liffey
and Rye Water/Royal Canal. Much of the remaining Leixlip boundaries are built up and a lot
of street lighting is present.
Soprano pipistrelle Pipistrellus pygmaeus
Irish Status
(Taken from Roche et al., 2014)
Least Concern
European Status
Global Status
Estimated Irish Population Size
Irish Population Trend
Estimate Core Area (km2) (Lundy et al. 2011)
Least Concern
Least Concern
0.54 to 1.2 million (2007-2012)
2003-2013 ↑
62,020
Core Area (Lundy et al., 2011 and viewed on www.nbdc.com)
The modelled Core Area for soprano pipistrelle is a large area that covers much of the island
of Ireland (62,020 km2). Strongholds include east Clare, west Galway and the
Monaghan/Fermanagh area.
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Habitat Preference/Avoidance (Lundy et al., 2011 and viewed on www.nbdc.com)
The Irish Landscape Model indicated that the soprano pipistrelle selects areas with broadleaf
woodland, riparian habitats and low density urbanisation (Roche et al., 2014). This array of
preferred habitats reflects the type of habitats present in the environs of Leixlip.
Population Trend (Roche et al., 2014)
Bat Conservation Ireland Irish Bat Monitoring Programme has reported a steady incline in
the soprano pipistrelle numbers since 2003 when monitoring by the Car-based Bat
Monitoring Scheme was set up.
Concerns (Roche et al., 2014)
Principal concerns for soprano pipistrelles in Ireland that are relevant for this survey area are
as follows:
- Lack of knowledge of roosts
- Renovation or demolition of structures
- Tree felling
- Increasing urbanisation (e.g. increase in lighting)
Leisler’s bat Nyctalus leisleri
Irish Status
(Taken from Roche et al., 2014)
Near Threatened
European Status
Global Status
Estimated Irish Population Size
Irish Population Trend
Estimate Core Area (km2) (Lundy et al. 2011)
Least Concern
Least Concern
73,000 to 130,000 (2007-2013) Ireland is
considered the world stronghold for this
species
2003-2013 ↑
52,820
Core Area (Lundy et al., 2011 and viewed on www.nbdc.com)
The modelled Core Area for Leisler’s bats is a relatively large area that covers much of the
island of Ireland (52,820 km2). A large contiguous area spans the east and middle of the
island with particular favourable areas in south Clare, east Wicklow, north Monaghan and
north Cavan.
Habitat Preference/Avoidance (Lundy et al., 2011 and viewed on www.nbdc.com)
The Irish Landscape Model indicated that the Leisler’s bat habitat preference has been
difficult to define in Ireland. Habitat modelling for Ireland shows an association with riparian
habitats and woodlands (Roche et al., 2014). The landscape model emphasised that this is a
species that cannot be defined by habitats preference at a local scale compared to other
Irish bat specie but that it is a landscape species and has a habitat preference at a scale of
20.5km. In addition, of all Irish bat species, Leisler’s bats have the most specific roosting
requirements. It tends to select roosting habitat with areas of woodland and freshwater such
as estate grounds and the River Liffey. The array of suitable stone buildings and large
mature trees on the estate is an essential component for the bat species.
Population Trend (Roche et al., 2014)
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Bat Conservation Ireland Irish Bat Monitoring Programme has reported a steady incline in
the Leisler’s bats numbers since 2003 when monitoring by the Car-based Bat Monitoring
Scheme was set up.
Concerns (Roche et al., 2014)
The principal concerns for Leisler’s bats are poorly known in Ireland but those that are
relevant for this survey area are as follows:
- Selection of maternity sites is limited to specific habitats
- Relative to the population estimates, the number of roost sites is poorly recorded.
- Tree felling, especially during autumn and winter months
- Increasing urbanisation
Daubenton’s bat Myotis daubentoni
Irish Status
(Taken from Roche et al., 2014)
Least Concern
European Status
Global Status
Estimated Irish Population Size
Irish Population Trend
Estimate Core Area (km2) (Lundy et al. 2011)
Least Concern
Least Concern
81,000 to 103,000 (2007-2012)
2008-2013 Stable
41,285
Core Area (Lundy et al., 2011 and viewed on www.nbdc.com)
The modelled Core Area for Daubenton’s bats is a relatively large area that covers much of
the island of Ireland (41,285 km2) reflecting the distribution of sizeable river catchments.
Particularly favourable areas are in include the Corrib, Shannon and Erne Catchments.
Habitat Preference/Avoidance (Lundy et al., 2011 and viewed on www.nbdc.com)
The Irish Landscape Model indicated that the Daubenton’s bat habitat preference is for
areas with broadleaf woodland, riparian habitats and low density urbanisation (Roche et al.,
2014). The River Liffey, Rye Water and Royal Canal potentially provides roosting sites
through the year for this species. The array of suitable stone buildings and large mature
trees is an essential component for the bat species.
Population Trend (Roche et al., 2014)
Bat Conservation Ireland Irish Bat Monitoring Programme has reported that this species is
stable from 2006-2013.
Concerns (Roche et al., 2014)
Principal concerns for Leisler’s bats is poorly known in Ireland but those that are relevant for
this survey area are as follows:
- Potential roost loss due to bridge maintenance
- Loss of woodland and forest clearance
- Loss of woodland, scrub and hedgerows
- Tree surgery and felling
- Increasing urbanisation
- Light pollution
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Common pipistrelle Pipistrellus pipistrellus
Irish Status
(Taken from Roche et al., 2014)
Least Concern
European Status
Global Status
Estimated Irish Population Size
Irish Population Trend
Estimate Core Area (km2) (Lundy et al. 2011)
Least Concern
Least Concern
1.2 to 2.8 million (2007-2012)
2003-2013 ↑
56,485
Core Area (Lundy et al., 2011 and viewed on www.nbdc.com)
The modelled Core Area for common pipistrelles is a large area that covers much of the
island of Ireland (56,485 km2) which covers primarily the east and south east of the area
(Roche et al., 2014). Particularly suitable areas include east Clare, Kilkenny, Laois, south
Offaly, Galway, Monaghan and east Wicklow.
Habitat Preference/Avoidance (Lundy et al., 2011 and viewed on www.nbdc.com)
The Irish Landscape Model indicated that the common pipistrelle selects areas with
broadleaf woodland, riparian habitats and low density urbanization (<30%) (Roche et al.,
2014). This array of preferred habitats reflects the type of habitats present in Raheen
woodland and Lough Derg.
Population Trend (Roche et al., 2014)
Bat Conservation Ireland Irish Bat Monitoring Programme has reported a steady incline in
the common pipistrelle numbers since 2003 when monitoring by the Car-based Bat
Monitoring Scheme was set up.
Concerns (Roche et al., 2014)
Principal concerns for common pipistrelle in Ireland that are relevant for this survey area are
as follows:
- Lack of knowledge of roosting requirements
- This species has complex habitat requirements in the immediate vicinity of
roosts. Therefore careful site specific planning for this species is required in order
to ensure all elements are maintained.
- Renovation or demolition of derelict buildings.
- Tree felling
- Increasing urbanisation (e.g. increase in lighting)
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4.
Management in view of Bat Fauna recorded
This report will draw on guidelines already available in Europe and will use the following
documents:
●
A conservation plan for Irish vesper bats, Irish Wildlife Manual No. 20 National Parks
and Wildlife Service, Department of Environment, Heritage and Local Government,
Dublin, Ireland.
●
Bat Mitigation Guidelines for Ireland. Irish Wildlife Manuals, No. 25. National Parks
and Wildlife Service, Department of Environment, Heritage and Local Government,
Dublin, Ireland.
●
National Biodiversity Plan. Department of Arts, Heritage, Gealtacht and the Islands.
●
The status of EU protected habitats and species in Ireland: Conservation status in
Ireland of habitats and species listed in the European Council Directive on the
Conservation of Habitats, Flora and Fauna 92/43/EEC. National Parks and Wildlife
Service, Department of Environment, Heritage and Local Government.
4.1
Ecological Assessment
The following bat species have been recorded during this bat survey: common pipistrelle,
soprano pipistrelle, brown long-eared bat, Myotis species and Leisler’s bats.
In summary, the proposed development will need to consider the following:
a. Bats and their bat roosts are protected by Irish legislation (Wildlife Act 1976
and 2000 Amendment) which make it an offence to wilfully interfere with or
destroy the breeding or resting place of these species. All species of bats are
listed in Schedule 5 of the 1976 Act and therefore are subject to the
provisions of Section 23.
b. The EU Habitats Regulations Directive 1992 seeks to protect rare and
vulnerable species, including all species of bats. All ten species of bat are
protected with the lesser horseshoe bat listed as an Annex II species while all
other bats (commonly known as vesper bats) are listed as Annex IV species.
c. Local Planning Authorities are required to give consideration to nature
conservation interests under the guidance of the SEA Directive 2001/42/EC.
This directive states that the protected status afforded to bats means that
planning authorities must consider their presence in order to reduce the
impact of developments through mitigation measures.
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d. The National Biodiversity Plan confers general responsibilities on all
participants in the development process to take into account of protected
species. “The overall objective is to secure the conservation, and where
possible the enhancement, and sustainable use of biological diversity in
Ireland and contribute to conservation and sustainable use of biodiversity
globally”.
NPWS Conservation Status Assessment report for each of the species recorded is
presented in a summary below the species list:
Leisler’s bat Nyctalus leisleri (Species Code 1331)
Common pipistrelle Pipistrellus pipistrellus (Species Code 1309)
Soprano pipistrelle Pipistrellus pygmaeus (Species Code 5009)
Daubenton’s bats Myotis daubentonii (Species Code 1314)
All Irish bat species are given a Favourable Status in Republic of Ireland. The Irish
Leisler’s bat population is of International Importance. The principal pressures on Irish
bat species are as follows:
-
urbanized areas (e.g. light pollution)
-
bridge/viaduct repairs
-
pesticides usage
-
removal of hedges, scrub, forestry
-
water pollution
-
other pollution and human impacts (e.g. renovation of dwellings with roosts)
-
infillings of ditches, dykes, ponds, pools and marshes
-
management of aquatic and bank vegetation for drainage purposes
-
abandonment of pastoral systems
-
speleology and vandalism
-
communication routes: roads
-
forestry management
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4.2
Recommended Measures
The recommended measures are briefly list below with more detailed information provided
further down the report.
1.
Limit the amount of lighting to be within the town environs especially along treelines
and hedgerows and adjacent to potential roosts in structures and mature trees.
2.
Treelines/hedgerows should remain in-situ and remain protected from proposed any
future proposed developments. Mature trees with dead wood and crevices should be
retained.
3.
Mature trees with ivy growth should be retained as they provide insect prey items
during the autumn months.
4.
Crevices within stonework should be retained where possible as such crevices
provide roosting sites for bats.
5.
Habitats identified as important foraging areas for bats should be protected and
enhanced by planting gaps with native tree and shrub species.
6.
Landscaping measures should include night-scented plants and shrubs and should
only considered planting native species grown from native and, if possible, local
stock.
7.
Avoid the use of chemicals (weed killers etc.) within the management zone.
Undertake physical removal of weed species only.
8.
Plant additional native trees and shrubs, with a view of connecting existing treelines,
hedgerows and wooded areas.
9.
Plant night-scented plants in flower beds and on edges of vegetable areas to
increase bat foraging areas.
10.
Limit spot lighting on buildings, especially lighting that may spill onto habitats. This is
especially important in relation to the rivers, canal and woodlands as dark corridors
are essential for wildlife commuting.
11.
Erect Schwegler woodcrete bat boxes (www.jacobijayne.com) on trees adjacent to
golf course.
12.
Please see the BCIreland Tidy Towns guidelines for more ideas on what can be
achieved in your area. In addition, the BCIreland Bat Box guidelines should be
consulted.
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Education
1. Set up interpretation boards of the flora and fauna present within the survey area. Bat
Conservation Ireland can provide bat photographs for such boards. Information for
such boards has been provided in the appendix.
2. Become a member of BCIreland and support their conservation work.
3. Host a bat training event and join BCIreland bat monitoring schemes to collate
annual data on local bat populations.
Lighting
Lighting should not be installed as part of the proposed works as it deters some bat species
from foraging. Studies have shown that illumination levels as low as 0.06 lux can have an
effect on the behaviour of bats. Even a full moon night (0.02 lux) can reduce bat activity to
more sheltered, darker wildlife corridors and foraging areas (e.g. woodlands). The slower
flying broad-winged species (Natterer’s bats, Daubenton’s bats, whiskered bats, Brandt’s
bats, lesser horseshoe bats and brown long-eared bats) have been shown to avoid street
lights. In a study of a roost in Suffolk, UK, the numbers of Natterer’s bats, whiskered bats,
Daubenton’s bats and brown long-eared bats fell after the installation of street lights adjacent
to the roost being monitored.
A study on the above controls was undertaken by Emery (2008) and concluded that
shielding and masking of street lights can reduce light spillage by as much as 40%. While
internal and external louvers are more effective, the external louvers can reduce light
spillage by as much as 97%.
- It is important to maintain Dark Zones for foraging bats in areas where lighting is not
necessary. However, where lighting is required, this lighting should be placed at a
minimum height using the lowest lux value permitted for health and safety.
- The lighting should be directional on to the buildings only with no spillage of light to
adjoining habitats. To reduce light spillage from luminaries, lights that are designed
not to emit light at angles greater than 70 o from the vertical plane should be used.
Consequently a flat glass protector is often used to reduce light spillage. Other
methods to control light spillage:
a. Shields: these can be mounted on lamps to control direction of the light
b. Masking: part of the luminaries is painted to block light to control the direction of
the light
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c. Louvers’: either as internal or external slates organized in rows or at angles
depending on the direction of light control.
- No white light should be permitted as this has the greatest impact on bats. Low
pressure sodium lights have a minimum impact on bats. Lighting that has little or no
UV content have the least impact on bats.
Stone crevices
Crevices in stonework are often used as temporary roosts. Two roosts were recorded in two
bridges and a third bridge contains suitable crevices. Crevices recorded as bat roosts should
be retained as bat roosts. Other crevices that may require filling in order to ensure the
integrity of the bridge or the structure should only be hand-filled. Where possible, retain
some crevices to allow usage for individual bats. Where re-pointing of stonework is required,
care should be taken not to entomb bats within the crevices. It is important to listen for bats
and observe for any signs of dropping or urine stains to ensure that no bats are present.
Suitable crevices are 10cm wide, 2cm tall and 10cm deep. Please consult a bat specialist for
any clarification of this measure.
If a bat is encountered during the process please remove gently with a pair of gloves and
return to a safe crevice in another wall or remove to a bat box. A woodcrete bat box should
be erected on a mature tree adjacent to the structure on a mature tree, if possible. Or
consult the bat specialist or local NPWS Conservation Ranger.
Bat Box Scheme
Bats are very transient mammals and move around buildings and structures changing
roosting sites regularly, especially male bats and especially during the spring and autumn
months. Therefore constant vigilance is required when under taking proposed works. In the
event of a bat being located during works (outside the maternity season), a bat box should
be erected on a mature tree. This bat box should be used to re-locate bats if found during
works. In such events, please contact bat specialist or NPWS Conservation Ranger for
advise on the such situations.
Details of sourcing these boxes and erection can be supplied. ‘Schwegler’ woodcrete bat
boxes are recommended but other designs are available – timber, concrete and
concrete/sawdust).
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Bat Survey Report
A bat box scheme could also be considered as a management tool, especially to encourage
bats roosting along the canal length. Bat boxes can be hung on poles or erected on mature
trees. Bat tubes are also suitable to erect on vertical walls of structures located along the
canal.
In the event of mature trees being removed, a bat box scheme should be erected along the
canal to compensate for potential loss of bat roosts. For every three trees removed, a bat
box should be erected.
Plate1 & 2: Example of woodcrete bat boxes which can be hung on trees or buildings.
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References and Bibliography
Barratt, E. M., Deauville, R., Burland, T. M., Bruford, M. W., Jones, G., Racey, P. A., &
Wayne, R. K. 1997 DNA answers the call of pipistrelle bat species. Nature 387: 138 - 139.
Billington, G. E. & Norman, G. M. (1997) A report on the survey and conservation of bat
roosts in bridges in Cumbria, Kendal. English Nature.
Convention on the Conservation of European Wildlife and Natural Habitats (Bern
Convention) 1982.
Convention on the Conservation of Migratory Species of Wild Animals (Bonn Convention)
1979.
EC Directive on The Conservation of Natural habitats and of Wild Fauna and Flora (Habitats
Directive) 1992.
Jefferies, D. J. (1972) Organochlorine Insecticide Residues in British Bats and their
Significance. J. Zool. Lond. 166: 245 - 263.
Kelleher, C. 2005 International Bat Fieldcraft Workshop, Killarney, Co. Kerry. National Parks
and Wildlife Service, Department of the Environment, Heritage and Local Government.
Mullen, E. 2007 Brandt’s Bat Myotis brandtii in Co. Wicklow. Irish Naturalists’ Journal
28: 343.
O’Sullivan, P. 1994. Bats in Ireland. Special supplement to the Irish Naturalists’ Journal.
Racey, P. A. & Swift, S. M. 1986 The residual effects of remedial timber treatments on bats.
Biol. Cons. 35: 205 - 214.
Richardson, P. 2000 Distribution atlas of bats in Britain and Ireland 1980 - 1999. The Bat
Conservation Trust, London, UK.
Whilde, A. 1993 Threatened mammals, birds, amphibians and fish in Ireland. Irish Red
Data Book 2: Vertebrates. Belfast: HMSO.
Wildlife Act 1976 and Wildlife [Amendment] Act 2000. Government of Ireland.
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Appendices
Bat ecology – general
The bat is the only mammal that is capable of true flight. There are over 1,100 species
worldwide, representing almost a quarter of all mammal species. There are 47
species in Europe - in Ireland, ten species of bat are currently known to exist, which
are classified into two families, the Rhinolophidae (Horseshoe bats) and the
Vespertilionidae (Common bats).
Prey
All the European bat species feed exclusively on insects. A Pipistrelle, weighing only 4
to 8 grammes, will eat up to 3000 insects every night, ensuring a build up of fat in the
bat’s body to allow it to survive the winter deep in hibernation.
Breeding and longevity
Irish bats can produce one young per year but, more usually, only one young is born
every two years (Boyd & Stebbings, 1989). This slow rate of reproduction inhibits
repopulation in areas of rapid decline. Although bats have been known to live for
twenty or more years, this is rare as most die in their first and the average lifespan, in
the wild, is four years.
Threats
All bat species are in decline as they face many threats to their highly developed and
specialised lifestyles. Many bats succumb to poisons used as woodworm treatments
within their roosting sites (Racey & Swift, 1986). Agricultural intensification, with the
loss of hedgerows, treelines, woodlands and species-rich grasslands have impacted
bat species also. Habitual roosting or hibernation sites in caves, mines, trees and
disused buildings are also often lost to development. Summer roosts are prone to
disturbance from vandals. Agricultural pesticides accumulate in their prey, reaching
lethal doses (Jefferies, 1972). Chemical treatments in cattle production sterilise dung
thus ensuring that no insects can breed within it to be fed upon by bats. Likewise, river
pollution, from agricultural runoff, reduces the abundance of aquatic insects. Road
building, with the resultant loss of foraging and roosting sites is a significant cause in
the reduction of bat populations across Europe.
Extinction
As recently as 1992, the greater mouse-eared bat Myotis myotis became the first
mammal to become extinct in Britain since the wolf in the 18th century.
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Ireland Red List No. 3: Terrestrial Mammals
Bats
Species: Common
Name
Irish Status
European Status
Global Status
Brandt’s bat
Data deficient
Least Concern
Least Concern
Daubenton’s bat
Least Concern
Least Concern
Least Concern
Whiskered bat
Least Concern
Least Concern
Least Concern
Natterer’s bat
Least Concern
Least Concern
Least Concern
Leisler’s bat
Near threatened
Least Concern
Least Concern
Nathusius’
pipistrelle
Least Concern
Least Concern
Least Concern
Common
pipistrelle
Least Concern
Least Concern
Least Concern
Soprano
pipistrelle
Least Concern
Least Concern
Least Concern
Brown long-eared Least Concern
bat
Least Concern
Least Concern
Lesser horseshoe Least Concern
bat
Least Concern
Least Concern
Marnell, F., Kingston, N. & Looney, D. (2009) Ireland Red List No. 3: Terrestrial Mammals,
National Parks and Wildlife Service, Department of the Environment, Heritage and Local
Government, Dublin, Ireland.
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Bat Survey Report