Project with bat boxes was launched as a result of need to provide roosts for some forest-dwelling or fissure-dwelling species they require holes or fissures in trees for roosting, mating and breeding. Due to the lack of mature forests with old trees and increasing presence of altered habitats, the availability of natural roost has dramatically decreased. Bat boxes are a compensatory measure, and therefore should not be used as definitive replacement for natural roosts.

Nevertheless, it is important to know the number of individuals and which species might occupy them. The monitoring is mainly focused on urban species such as common pipistrelle (Pipistrellus pipistrellus), soprano pipistrelle (Pipistrellus pygmaeus), Kuhl’s pipistrelle (Pipistrellus kuhlii), Nathusius’ pipistrelle (Pipistrellusnathusii) and forest-dwelling species such as Leisler’s bat (Nyctalus leisleri), giant noctule (Nyctalus lasiopterus), brown and grey long-eared bats (Plecotus auritus and Plecotus aurstriacus), greater mouse-eared bat (Myotis myotis), Iberian Natterer’s bat (Myotis escalerai), Bechstein’s bat (Myotis bechsteinii) and western barbastelle (Barbastella barbastellus).


Who can participate?

Monitoring of the bat boxes is aimed to wide public, from more specialized to more familiar. Depending on the degree of knowledge about bats, this monitoring can be done in two ways. However, if you have any questions, you can contact us at .

Where it can be carried out?

This monitoring can be carried out in any habitat and location; you just need to install a bat box and monitor it (or you can track some bat box from our network that is available). Before starting you should ensure that the box you want to follow is not being monitored by another person. Because of that, you will need to sign up and check the availability of every bat box.

What does it consist of?

Photographing and counting bats

When it should be carried out?

It is very easy. This monitoring is carried out throughout whole year. Bat boxes are being checked once per season of the year (winter, spring, summer and autumn).

How is it carried out?

Based on your experience, it can be carried out in two ways:

  1. Staff without experience: monitoring is being performed at dusk by counting bats leaving the roost during the emergence. It is advised to stand relatively close to the bat box to be able to see the opening and all emerging animals, but always at a prudent distance to avoid any disturbance of bats. Depending on the species, emergence time might vary between some minutes before the sunset (for example common pipistrelle) and one hour after the sunset (Leisler’s bat).
  2. Experienced people: monitoring is being carried out during the day. Roost check is done by opening the box (that is possible to open) and taking the photograph of the interior to be able to count the animals and, if possible, to identify the species.

It is very important to remember that in any case animals must not be handled/manipulated!

The count can be barried out using a flashlight that allows illuminating the interior of bat box and taking photo.

Which equipment is needed/necessary?

Photo camera in case of counting animals from the photo

Sending and checking the results

Through web application you can access to the tools register your bat boxes, you can send us comments and see the results from another bat boxes within our monitoring network/system. The results must be submitted before the end of August. The data can be submitted online directly from the field, or it can be written down to field notebook and uploaded afterwards.

If you would like to participate or to join some training session in order to learn more about the monitoring, please do not hesitate to contact us!


Training sessions

Occasionally we organize training sessions in order to disseminate information about the monitoring, to encourage the volunteers and to provide them with the necessary knowledge to be able to carry out this simple protocol, for which previous knowledge about bats is not essential. An alternative to training sessions is to accompany other researchers during their fieldwork, and to obtain enough experience within one day to be able to carry out the procotol autonomously.


Bat boxes available online


Casas para pájaros


Gestió Natural

Guidelines to build your on bat box

Instructions (pdf): Model 1 / Model 2 / Model 3 Model 4 Model 5 Model 6 / Model 7 / Model 8 Model 9 / Model 10 / Model 11

Wood bat boxes (cavity):

Wood bat boxes (plain):

Wood bat boxes (2 cavities):

Kit construction: