Who can participate?

Anyone regardless of previous knowledge about bats can do it.

During single one-night training you can learn how to do it. We organise training sessions to explain the protocol. More information available in the Resources section.

Where can it be carried out?

Rivers, ponds and water reservoirs with slow waters.

Before starting a specific monitoring, you must sign up in this website from where you can easily set up your monitoring stations. If you prefer to re-activate an old transect contact us.

What does it consist of?

It consists of counting trawling bats (Myotis daubentonii/Myotis capaciniiand pipistrelle bats (Pipistrellus sp.) from four observing points.

How is it carried out?

 Each transect consists in 4 sampling points, separated about 300m. At each sampling point:

1) We stand on the river bank with the flashlight crossing the river, at the water level.

2) For 10 minutes we count all  trawling bats (Myotis daubentonii/Myotis capacinii) that cross the light.

3) We move the flashlight 45º up.

4) For 5 minutes we count all pipistrelle bats (Pipistrellus sp.).

We repeat the same protocol in all 4 points.

To learn how to distinguish the bats, check the Resources section.


One evening a year between June, July and August, without rain and strong winds. The survey always starts one hour after the sunset.

Which equipment is needed

A powerful flashlight and a field notebook.

Field sheet

Create you own transect

In this platform you have access to the tools to design and register your own transect. Create your own transect HERE.

Send the results

Once the survey is finished, you will be able to upload your observations to the website and check the results from other stations.

If you would like to participate or to join some training session please do not hesitate to contact us!


Training sessions

Periodically we organise training sessions to provide the necessary knowledge to carry out this protocol.

Keep an eye on our socials nets and sign up for our newsletter to be updated.

On-line training

  • Visual recognition of flight types: it is impossible, even for a bat expert, to distinguish the majority of bat species only based on their flight. Fortunately, trawling bats are an exception to this rule. They forage over the water bodies and have developed a flight strategy that is completely different from the rest of the species.

    • Typical flight behaviour of a trawling bat
      Animals usually make long twists, often repeated with insistence, always close to the surface of water. 

      Ruta de vol de Myotis daubentonii

    • Typical flight behaviour of a pipistrelle bat
      Very erratic without the maintaining a fixed height, often along the edge of the vegetation:

      Ruta de vol de Pipistrellus

    • Foraging behaviour of Daubenton's bats above the water surface recorded with an infrared camera and a heterodyne detector, at one little stream in England.