Bat House Forum

[Erik]

Hello everyone, in spring 2007 I made a video of bats inside a bat house just before and whilst flying out of the bat house. I thought I already posted it, but apparently not.
In Europe we have a small bat called Nathusius Pipistrelle. It is only 5-7 grams but it has a great migration ambition. Males stick to a fixed area the whole year round but females migrate between mating/hibernation areas and nursery roost areas. The mating/hibernation areas are in Western Europe. The nursery areas are about 600 miles (1000 km) to the east in Eastern Europe. In the fall we are used to find mating groups (1 male with a few females) in our small bat houses (small, single chambered).

Last year in early spring however we found big groups of (mostly) females in the same bat house. It seems that these bats gather along migration routes (congestion) and wait for the best weather to start migrating.
With our bat work group we organised an evening to count and film the bats in these bat house. The video shows bats waking up and getting ready to leave the bat house. You can see them groom produce droppings and pee (just missing the camera ).It was filmed with a Sony Mini-DV camera with 20x zoom and a IR-lightlamp.

Edited by Joe 12-27-08 since it was not appearing after forum upgrade



(to have a bigger and better view, check it out at:
http://video.google.nl/videoplay?docid=4617677660699475824&hl=nl)

[Terry Lobdell]

Erik, great video! Thanks for sharing! The way they move around and groom looks very much like our little browns and big browns here in the USA.

[Joe Spencer]

Erik, very nice video and thank you.  Don't have my glasses on. It appears to be mounted on a tree.  How high up? How many bat houses are there in this area and what is the distance to water if any?

Joe

[Erik]

Thanks Joe,
did you check out the link below the video? There you can watch the video in a bigger window. I am not sure right now but I think there are 17 bats in the bat house.

The bat house is mounted on a tree, about 6 meters (19 feet) high. The distance to the nearest water is just a few meters (10-20 meters at most [30-60 feet]). There are about 15 bat houses mounted on trees around a small lake. The lake is near a river valley, which is a known migration route for this species (Nathusius pipistrelle).
The bat houses are mounted and checked by Peter Twisk, a very good bat worker and nature illustrator. The site was a pilot project for the bat house project of the bat work group I am a member of.

The bat house is used by these bats as a stepping stone in there migration and as mating roosts. In cold winter no bats use the boxes, but in mild winter we find just a few bats. In early spring females seem to gather in the boxes, waiting for the right weather to start there journey to Eastern Europe (only females migrate). In summer the boxes are sometimes used by single males but august they start to defend there bat house and the surrounding bat houses against other males. At the same times they use social calls to attract females (back from the East) to their bat house and gather a harem of females.

They are Small bats with great spirits! Only yesterday I caught a female during research at a hibernation / autumn swarming site. It was so cool to realise that this small bat probably flew over 1000 km (> 620 miles) in the past weeks.

greetings,

Erik

[Cheryl]

Wonderful video, Erik! I'm sending the link to some family and friends who also like bats! (Fun to watch the little bats grooming themselves as they get ready to launch.)

[dasycneme]

Nice video, what equipment was used? It looks like a nightscope (green) I am using either Sony or security cameras with infra red illuminators, just interested in what others use.  Tip:-I also plug a bat detector into 'sound in' this stops the conversation of crows and people in the background.  Keep up the good work Erik, it is really useful.
Roger :D

[Erik]

Hi Dasycneme,

a Sony Mini-DV cam (Nightshot Plus) was used, in combination with a IRLight (I believe the IR 60).
Plugging in a bat detector in the audio line in of the camcorder is indeed better, but in this case I think it is also nice to hear the geese on the background and the cheering voice of the people (everytime a bat left the bat house).

Erik

[Joe Spencer]

Thank you very nice indeed!