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 in Brussels

Alex Lefevre Bob Vandendriessche What about the bat species richness of Brussels ? Bat species in Belgium Annexe II Status

winter summer Rhinolophus hipposideros Yes = present in Rhinolophus ferrumequinum Yes Brussels Barbastella barbastellus Yes Myotis emarginatus Yes Myotis bechsteinii Yes Myotis myotis Yes Myotis brandtii Myotis alcathoe Myotis mystacinus Myotis daubentonii Myotis dasycneme Yes Myotis nattereri auritus Plecotus austriacus pipistrellus Pipistrellus nathusii Pipistrellus pygmaeus noctula Nyctalus leisleri serotinus murinus 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 Type Geslacht Lotgevallen vindplaats/gebied 1948? Amay? Maas Onbekend ? Collectie KBIN 20/09/89 Blankenberge Kust Gevel woonhuis Man? Gelost 7/7/99 Knokke Kust Spouw flatgebouw Vrouw? Kraamkolonie? 30/11/00 Libramont Ourthe Hospitaal Man Gelost 20/08/01 Boncelle Maas/Ourthe Zolder woonhuis Man Dood 30/05/02 Oostende Kust Portaal flatgebouw Vrouw Gelost i.s. 18/08/02 De Panne Kust Gevel flatgebouw ? Gelost i.s. 10/09/02 Hotton (Ny) Ourthe Kippenhok Vrouw Gelost i.s. 04/12/04 Oostende Kust Gevel Man Gelost i.s. 25/08/05 Moeskroen Schelde Stortplaats Vrouw Gelost i.s. 22/05/06 Tessenderlo Limburg Open fabrieksloods Vrouw Gelost in Oostende! 25/09/06 Laken Brussel Straat Man Collectie KBIN 30/09/06 Oostende Kust Gevel thermen ? Zelfde als 08/10? 08/10/06 Oostende Kust Gevel thermen ? Weggevlogen 08/10/06 Oostende Kust Gevel flatgebouw Vrouw Zelfde als 08/10 en 30/09? Gelost i.s. 19/02/07 Bocholt Maas Straat Man Dood 20/02/07 11/01/08 Brussel, E.J.- Brussel Straat ? ? laan 16/10/08 Kortessem Limburg Straat Man Dood kort nadien x/05/09 Damme Kust Kanaal ? Jagend waargenomen 24/09/09 Oostende Kust Gevel thermen e.o. ? Laatst gezien 26/09 29/09/09 Knokke Kust Straat ? Dood 30/09 20/08/10 Wijnegem Schelde Straat ? Gelost Brasschaat 03/10/10 ? Kust ? Jagend waargenomen 08/10/10 Blankenberge Kust De zeepier man VOC, dag zelf gelost, nadien baltsend waargenomen! 11/10/10 Maasmechelen Maas Gevel ? Kort nadien gelost 12/10/10 Antwerpen- Schelde Straat man Gelost 13/10/10 Luchtbal 19/10/10 Middelkerke Kust Straat man Gelost 27/04/11 Regio Maas ? ? Maasmechelen

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 . 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 …