All mammalian hibernators arouse periodically throughout the winter and weather change conditions is one of the major drivers affecting their behaviour, phenology and distribution patterns worldwide, with potentially severe implications for biodiversity conservation. Although the relationships between bat distribution and prevailing environmental conditions are relatively well-known, the behaviour adaptation responses to scenarios of weather change conditions are still largely unknown. Temperate insectivorous bats show different ecological requirements for winter activity and bouts frequency depending on the species and weather prevailing condition. The European free-tailed bat (Tadarida teniotis) is a non-strictly hibernating bat species, characterized by short periods of torpor in contrast with other species from the Vespertilionidae and Rhinolophidae families, which are strictly hibernating bat species. This study was carried out in a Mediterranean region providing unique information on daily winter bat activity patterns with relevance for the understanding how instantaneous and cumulative weather conditions influenced non-strictly and strictly hibernating bat species winter activity patterns to anticipate ecological consequences under future climate change scenarios. Our results clearly demonstrate that instantaneous and cumulative weather conditions induce different behavioural responses on non-strictly and strictly hibernating bat species concerning winter activity, highlighting the importance of cumulative weather conditions for strictly hibernating bat species. Therefore, the understanding of the role of behavioural plasticity among bat communities to cope with changing weather conditions is critical, particularly for the activity patterns of the strictly hibernating bat species during hibernation. This is fundamental to anticipate the potential ecological consequences and the main challenges and priorities for bat conservation.

The authors are indebted to the staff of the Laboratory of Applied Ecology from UTAD (University of Trás-os-Montes and Alto Douro), especially to Diogo Carvalho who assisted in the Geographic Information System for study area map elaboration and in the early revision of the manuscript. We would also like to thank the two anonymous reviewers for their pertinent comments and suggestions, considerably improving this manuscript.

This work is supported by National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020 (Centre for the Research and Technology of Agro-Environmental and Biological Sciences) and funding from several ecological monitoring projects carried out by the Laboratory of Applied Ecology including the grants BGCT/PIMA/0246/59/2016 (PB) and BGCTL/UTAD/10/2019 (SF).