Stefan Fa├čbender


Effectiveness of constructions against feral pigeons and their accessibility for bats.

Feral pigeons (Columba livia) and several bat species use large roof spaces as roosting sites. Noise and permanent movement by feral pigeons disturb bats which need rest during daytime. This is especially the case during the raise of juveniles. The dilemma can be solved by constructions which are supposed to be passable for bats whereas feral pigeons should be kept out. There are currently no scientific studies about the effectiveness of these constructions.

In this work three different constructions were examined in two different experiments: Fassbender2

1) the effectivity in protecting openings against feral pigeons was tested in aviaries and

2) the accessibility of these openings for bats were examined in flight tent experiments.

Pigeon experiments revealed an influence on the passability of openings by several constructions. However, only two out of six tested constructions were completely impassable for feral pigeons. Passable construction were also passable in the other direction. It can be concluded that there is no trap effect. Bat experiments reveal that only a minority of the three tested individuals were able to pass a construction, whereas the control group (free opening) succeeded in leaving the flight in a predominant amount of treatments. The recommended and used constructions do not satisfy the requirements of effective pigeon deterrence under high pigeon pressure. Furthermore, the experiments leave reservation about the passability for bats. Hence, it is necessary to conduct further studies and optimize the constructions.