The objective of this study is to increase our knowledge of the ecology of the greater mouse-eared bat (Myotis myotis), to achieve a better understanding of its prey selection strategy during the breeding season, and the resulting choice of hunting sites. We developed 4 work packages with the aim to answer various questions raised in the results of a study carried out in 2023 by the same authors:

1. Do the greater mouse-eared bats select coniferous forests over other forest stands for hunting? If so,
2. when and why?
3. Do the greater mouse-eared bats hunt in spruce stands throughout the summer season?
4. What is the supply of forest stands around the studied greater mouse-eared bats maternity roosts ?
5. Why do the greater mouse-eared bats equipped with GPS tags all follow the same direction when outflying their maternity roost?
6. What is the diet of the greater mouse-eared bats, and how does it change over the season? Is the ecology of preys linked to a particular type of forest stand?

The work packages of this study are :

An acoustic approach to measure the use of different forest habitats, coupled with a statistical analysis of the relationships between the greater mouse-eared bat activity and habitat characteristics: we assessed the greater mouse-eared bat activity with ultrasonic batdetectors in 36 forest stands, with 18 resinous/deciduous pairs, in 2 distinct geographical areas (Lorraine and the Pays de Herve - Ardenne, Wallonia - Belgium), close to

greater mouse-eared bat maternity roosts (Ethe and Lontzen).

A characterisation of the habitats available in the vicinity of the maternity roosts studied (cartographic approach): we extracted the various significant parameters resulting from the acoustic approach in a 15 km buffer area around the two studied maternity roosts. We combine the restulting maps with the azimuths adopted by the GPS-tagged greater moused-eared bats (2023) towards their hunting sites.

A diet study, based on DNA-analysis of droppings: we collected 10 samples of fresh droppings in the two maternity roosts of Ethe and Lontzen on 6 sampling sessions over the spring-summer season, leading to a total of 120 samples.