Flits Tweekleurige Vleermuis

Flits Tweekleurige Vleermuis
14/09/2015
Beste Vleerders,
het actieve vlerenseizoen loopt stilaan op z’n einde maar dat betekent uiteraard niet dat
er niks meer te beleven valt. Berg je detector dus nog niet op…
In deze periode kunnen we namelijk uitkijken naar de Tweekleurige vleermuis. Vanaf
augustus/september kan deze soort al waargenomen worden maar tussen oktober en
december is die kans het grootst. Bvb in Scandinavische en Oost-Europese steden
worden Tweekleurige vleermuizen nog waargenomen bij -10°C en 2 m sneeuw.
Tot op heden werd deze soort in Oost-Vlaanderen nog niet waargenomen, in
tegenstelling tot onze naburige provincies. Het feit dat er weinig of niet naar wordt
gezocht is een mogelijke oorzaak. Vandaar de warme oproep om actief op zoek te
gaan naar deze soort. En een goeie reden om gezellig in de stad te gaan kuieren met je
detector op zak.
Tweekleurige vleermuizen maken in deze periode een zeer karakteristiek geluid, nl de
zangvlucht zoals je in bijlage kan horen. Het beste is om tijdens een warme en droge dag
vroeg in de avond post te vatten aan de zuidkant van hoge gebouwen (= vanaf 4
verdiepingen dus flatgebouwen, kerken, kastelen, oude fabrieken…) en per locatie een
kwartier te luisteren. Deze dieren gebruiken de wanden van hoge gebouwen als
klankbord als alternatief voor de rotswanden die ze oorspronkelijk gebruikten. De
frequentie is zeer laag, nl. 14 kHz en ze zijn dus ook met ’t blote oor te horen, al zal
enkel een geoefend oor dit geluid kunnen onderscheiden. Dus je kunt best eerst
afspeuren met de detector en dan trainen om het geluid zonder detector te kunnen
determineren. Probeer daarbij een opname te maken voor determinatie en mail ’t ons
door.
In het gekoppelde document vind je meer gedetailleerde informatie.
Mvg,
Vleermuizenwerkgroep Oost-Vlaanderen
Looking after the
Parti-coloured bat in
Brussels
Alex Lefevre
Bob Vandendriessche
What about the bat species richness
of Brussels ? Bat species in Belgium
Annexe II
Status
winter
= present in
Brussels
Rhinolophus hipposideros
Yes
Rhinolophus ferrumequinum
Yes
Barbastella barbastellus
Yes
Myotis emarginatus
Yes
Myotis bechsteinii
Yes
Myotis myotis
Yes
Myotis brandtii
Myotis alcathoe
Myotis mystacinus
Myotis daubentonii
Myotis dasycneme
Myotis nattereri
Plecotus auritus
Plecotus austriacus
Pipistrellus pipistrellus
Pipistrellus nathusii
Pipistrellus pygmaeus
Nyctalus noctula
Nyctalus leisleri
Eptesicus serotinus
Vespertilio murinus
Yes
summer
The parti-coloured bat in a
city?
Vespertilio murinus
Linnaeus, 1758
•
•
•
•
UK: Parti-coloured bat
FR: Sérotine bicolore
NL: Tweekleurige vleermuis
DE: Zweifarbfledermaus
Distribution Vespertilio murinus
V. murinus murinus
V. murinus ussuriensis
Distribution in Belgium
(data Bob Vandendriessche)
Datum
Plaats
Regio
Geslacht
Lotgevallen
Maas
Kust
Kust
Ourthe
Maas/Ourthe
Kust
Kust
Ourthe
Kust
Schelde
Limburg
Brussel
Kust
Kust
Kust
Type
vindplaats/gebied
Onbekend
Gevel woonhuis
Spouw flatgebouw
Hospitaal
Zolder woonhuis
Portaal flatgebouw
Gevel flatgebouw
Kippenhok
Gevel
Stortplaats
Open fabrieksloods
Straat
Gevel thermen
Gevel thermen
Gevel flatgebouw
1948?
20/09/89
7/7/99
30/11/00
20/08/01
30/05/02
18/08/02
10/09/02
04/12/04
25/08/05
22/05/06
25/09/06
30/09/06
08/10/06
08/10/06
Amay?
Blankenberge
Knokke
Libramont
Boncelle
Oostende
De Panne
Hotton (Ny)
Oostende
Moeskroen
Tessenderlo
Laken
Oostende
Oostende
Oostende
?
Man?
Vrouw?
Man
Man
Vrouw
?
Vrouw
Man
Vrouw
Vrouw
Man
?
?
Vrouw
Maas
Brussel
Straat
Straat
Man
?
16/10/08
x/05/09
Bocholt
Brussel, E.J.laan
Kortessem
Damme
Collectie KBIN
Gelost
Kraamkolonie?
Gelost
Dood
Gelost i.s.
Gelost i.s.
Gelost i.s.
Gelost i.s.
Gelost i.s.
Gelost in Oostende!
Collectie KBIN
Zelfde als 08/10?
Weggevlogen
Zelfde als 08/10 en
30/09? Gelost i.s.
Dood 20/02/07
?
19/02/07
11/01/08
Limburg
Kust
Straat
Kanaal
Man
?
24/09/09
29/09/09
20/08/10
03/10/10
Oostende
Knokke
Wijnegem
?
Kust
Kust
Schelde
Kust
Gevel thermen e.o.
Straat
Straat
?
?
?
?
08/10/10
Blankenberge
Kust
De zeepier
man
11/10/10
12/10/10
Maasmechelen
AntwerpenLuchtbal
Middelkerke
Regio
Maasmechelen
Maas
Schelde
Gevel
Straat
?
man
Dood kort nadien
Jagend
waargenomen
Laatst gezien 26/09
Dood 30/09
Gelost Brasschaat
Jagend
waargenomen
VOC, dag zelf
gelost, nadien
baltsend
waargenomen!
Kort nadien gelost
Gelost 13/10/10
Kust
Maas
Straat
man
?
Gelost
?
19/10/10
27/04/11
Number of observations
per month (data Bob Vandendriessche)
8
7
6
5
4
3
2
1
0
1
2
3
4
5
6
7
8
9
10
11
12
And what about Brussels?
Population (1)
• An abundant species in northern parts of its European range.
• Populations are expanding in some parts of the range, for example
Denmark (H. J. Baagøe pers. comm.) and the Netherlands
(H.J.G.A. Limpens pers. comm.). This species has a wide
distribution, but a low abundance within Mongolia (M. Stubbe pers.
comm.).
• This nocturnal species appears late in the evening, sleeping in
narrow crevices during the day.
• Forages at 10 – 40 m height, in straight flight in the open air over
many different landscape types.
• Feeds on small dipterans, beetles and moths.
Population (2)
• They live in small colonies and often single individuals are sighted.
• Summer maternity colonies number of 30-50 (exceptionally 200)
females in low, often modern and well-insulated houses, sometimes
in hollow trees and nest boxes (Russia).
• Young are born in June/July, generally 2 are born at a time, and are
stuck onto the chest of the mother during flight.
• Males may also form large colonies in summer. In winter it usually
occurs singly or in small groups (although clusters of up to 30 have
been recorded).
• Hibernates throughout the winter, mainly in buildings, often in big
cities.
Long distance migration are known, of up to 1,780 km have been
recorded, although the species is sedentary in a large part of its
range.
When do we have to look
after this species?
Sometimes the species can be heard in August or September.
The most intensive period however is much later in the year: as far
as we know, from the end of October until into December.
In towns such as Uppsala and Kiev, males can be found song
flighting when the snow is 2 m thick and the temperature is -10°C.
In Copenhagen you might be walking through the centre of the
town, wrapped up warm, in a big crowd of people shopping for
Christmas presents, while above you the air is full of song flighting
parti-coloured bats.
How to inventory?
• Go out early in the evening, to listen on the southern side of tall
buildings.
• Do it especially after relatively warm and dry afternoons.
• Stay at each building for about a quarter of an hour.
• The more buildings can be surveyed, the higher the chance that we
will find a song flighting male parti-coloured bat. At buildings where
you can listen easily, because they are close to you, or you go past
them on your way to the pub, or whatever, it is certainly useful to
listen repeatedly.
• If you think you have heard something, try to make a recording.
• Send your recording to us (heterodyne or time-expantion). We will
then listen, and possibly go back with you to make more recordings
to get more certainty.
Some evidence from the
literature (1)
•Some evidence from the
literature (2)
Song flights of
particoloured bats
• The particoloured bat is also a song flighting bat, which has its own
version of the song flight.
• The peak frequency of the song flight call is approximately 14 kHz.
Without a bat detector, the sound is a high "zing" which is repeated
approximately 4 or five times per second in a continuous rhythm
"….zing….zing….zing….zing…."
• If there are many males song flighting, the air is filled with a
zooming sound, similar to the sound made by cicadas in southern
Europe, but at a higher frequency.
• If you listen with your bat detector set to 14 kHz, it sounds like
"pwooit…pwooit…pwooit". The "pwooit" is preceded by a series of
very short pulses which sound like "trrrrrr" This trill can be heard in
the background of the "pwooit" sounds.
Searching for song-flighting
parti-coloured bats
•
•
•
•
•
The males often fly in front of a flat object which reflects sound. In built-up areas, for
example, they song flight in front of south-facing sides of tall buildings, such as
blocks of flats, cathedrals, castles and churches.
In nature they use south-facing cliffs. Even though they do song flight at
temperatures below zero, they probably search for places where the midday sun has
produced slightly higher temperatures. But sometimes you also find them song
flighting above a small village in the mountains. The puzzle is far from complete.
Let's use the sound made by the males during song flighting in a positive way, and
search for song flighting parti-coloured bats.
The calls are also audible without a detector. Because our ears have a large range,
and compared to a detector are quite sensitive, sometimes it is easier to hear the
sound without a detector. The problem is that you must be aware of what you hear.
14kHz is much higher than most of the sounds we hear, and many people do hear it,
but don't perceive it. Being certain that it is a bat, and possibly a song flighting
particoloured bat, is easier with the detector, particularly if you have never heard the
sound before. Swap between listening with a detector and listening without detector.
Once you have heard the sound once and you know it, you will use your ear to
search more than you will use your detector.
A recording
Sonogram BatSound
Opname te Wenen, 2007
Some sounds
•Hunting (HET)
•Song (HET)
•Song (TE)
Hunting
•Social call noctule (TE) serotine (HET)
•A special casus: Ostend
•A special casus: Ostend
And now let’s find them.
Special thanks to Herman Limpens, Jules
Agate and Ingemar Ahlen for their
recordings.
Thanks for your attention and now let’s start
searching after the parti-coloured bat!
•The first to record it in Brussels will receive
a bottle of …