British Bats

By Sue Searle

Key Bat Facts

• 17 species breeding in the UK

• All of these are ‘Microchiroptera’

• Only flying mammals

• Long-lived – up to 30 years

• Pipistrelle is thumb-size

• British bats only eat insects

Bats around the World

• >950 species

• Almost ¼ of all mammal species are bats!

• Order Chiroptera – means hand wing

• Only mammals able to undertake powered flight

• Wing is formed from thin membrane of skin stretched between the foot and the finger tips

Distorted truth!

‘As blind as a

bat’

•No British bats drink blood – they eat insects

•3 bat species worldwide drink blood from large animals

•Only in Central and Southern America

•Bats look like they are baring their teeth when they are echolocating

•However, if handled they may bite as a means of defence

Bats drink blood – they’re

vampires

Bats are aggressive – they bare their

teeth at you

•Not blind, but can’t see in colour

•Fairly good night vision – good sensitivity rather than good resolution

•Only 10 UK bats have tested positive for carrying rabies virus

•Over 6000 bats tested since 1986

•Mainly Daubenton’s

Bats carry

rabies

Bats get in

your hair

Bats use Echolocation to find their way around. They do not usually knock into anything but sometimes they make a mistake!

Bat species in Britain

Vespertilonidae 3 pipistrelle species 6 Myotis species 3 ‘big bats’ 2 long-eared bat species Barbastelle Rhinolophidae Lesser horseshoe Greater horseshoe

British Bats Pipistrelles

•3 species

•Britain’s smallest bats

•Crevice dwellers

•Common pipistrelles and soprano .pipistrelles are Britain’s ..commonest bats

•Nathusius’ pipistrelle is rare but ..widespread

Soprano pipistrelle

Long-eared bats

•2 species

•Very long ears, joined at base

•Often roost along ridge beam in buildings

•Brown long-eared bats are ..common and widespread.

•Grey long-eared bats are rare ..and restricted to Southern ..England

Brown long-eared bat

British Bats Myotis bats

•Largest genus in Britain – 5 species •No post-calcarial lobe and paler fur on underside

•Crevice dwellers Natterer’s

-Favours ..woodland -Common and ..widespread

Daubenton’s -’water bat’ -Common and ..widespread

Bechstein’s

-long ears -Rare &.restricted -Woodland sp.

Brandt’s and Whiskered

-very similar -uncommon and not in Scotland

Alcathoe's Whiskered bat

first discovered in 2010, smallest

bat in UK

British Bats Barbastelle

•Black bat

•Unmistakeable appearance

•Prefers ancient woodland

•Rare but wide ranging

•Southern England and Wales

Big bats

• 3 species

•Noctule: Largest British bat, roosts in trees, common, not in northern Scotland or Ireland.

•Leisler’s: Smaller relative of noctule, common, stronghold in Ireland.

•Serotine: Different genus, shaggy fur and long tail.

Noctule Serotine

Leisler’s Barbastelle

Horseshoes

•2 species

•Distinctive nose leaf

•Hanging bats

•Greater horseshoe: pear sized, ..rare and restricted to south ..west England and Wales.

•Lesser horseshoe: plum sized, ..rare (less so than greater), ..south.west England, Wales and west.midlands.

Greater horseshoes Lesser horseshoe

British Bats Any other bats?

• Vagrants blown over from continent or arrive in shipments of wood – e.g. Geoffroy’s

•Greater mouse-eared bat. ..Only one bat known in Britain.

Greater mouse-eared

bat

Echolocation

• Ultrasound pulse from mouth or nose

• Sound reaches prey and is reflected

• Using time of reflection, the bat can calculate the distance

The Bat’s Wing Thumb

1st finger

2nd finger

Tail

4th finger Blood vessels

3rd finger

• Can you guess the species?!

Bat Habitat • Roost sites – barns, houses, caves, trees…

• Ideally mosaic of woodland, slow moving/still water

and grazed grassland

Good connectivity between roosts and feeding areas (e.g. bushy hedges/tree lines)

Different species have different habitat preferences

The Bat’s Year

Bat Roosts

• Bats roost in trees, buildings, caves and under bridges

• Only horseshoe bats actually hang

The Signs

• Piles of droppings

• Moth wings

• Greasy marks

• Gaps under eaves and in roof, and no cobwebs in them

Where would bat be roosting in a house?

Types of roosts

Hibernation

Summer

Night roost or feeding

perch

Maternity

Transitional

Mating

Bat Roosts

Pipistrelles

Lesser

horseshoes Brown long-eared

and pipistrelle

Lesser

horseshoes

Lesser horseshoes

Lesser horseshoes

Brown long-eared

Serotine

Tree roosts

Trees – splits, fissures

woodpecker holes, behind

ivy stems Man-made bat boxes

Veteran trees (roosts)

Bat Droppings

Mouse

or bat?

Hard Crumbly

Survey Timings and Effort

Survey

objective

Dusk survey Dawn survey

Bat activity away

from the roost

Sunset to 2-3 hours

after sunset1

2 – 1 ½ hours before

sunrise to sunrise

Bat emergence

from and re-entry

to roost

¼ hour before sunset to

1 ½ - 2 hours after

sunset2

2 – 1 ½ hours before

sunrise to 15 minutes

after sunrise3

Mating activity Sunset to 4 hours after

sunset

-

1 when site is larger than 1 ha and within 4 km of greater horseshoe bat roost, 3 hours is

required.

2 Some bats may emerge earlier than ¼ hour before sunset.

3 Some bats may return to their roost after sunrise.

From BCT Good Practice Guidelines

Seasonality Bat activity surveys

J F M A M J J A S O N D

Optimal period Sub-optimal period

Dusk emergence and dawn re-entry surveys

J F M A M J J A S O N D

Bat Conservation

• Bats have seriously declined

• Greater and lesser horseshoe endangered

• Nine other species are threatened

Reasons…

• Loss of roost sites

• Chemical timber treatment

• Decline of prey species

• Loss of hunting grounds

Bat Protection & Conservation

• Bats are fully protected by several pieces of legislation

• Together they prevent intentional killing, injuring or capture, disturbance and damage to a roost site.

• Licences are required

• Conservation: roost protection, regulation of building work, control of pesticide use

• Bat Conservation Trust

References

Bat Conservation Trust (2016). Bat Surveys – Good Practice Guidelines (3rd

Edition). Bat Conservation Trust, London

Mitchell-Jones A.J. and McLeish A.P. (2004). Bat Worker’s Manual (3rd

Edition). JNCC