Baixo Sabor: Bat Roosts - Ecological Monitoring Program (2008-2014)

Sampling was designed to cover all known and potential bat roosts in the study area, including railroad tunnels, caves, mines, wells, bridges and all sorts of buildings. A place was considered to be a roost when the presence of bats was confirmed, either by direct observations or by indirect evidences (e.g., faeces, urine stains, etc.). Each roost was visited once or twice per season, in the hibernation (January-February), reproduction (April-August) and pre-dispersion (September-October) periods, depending on the year.
All roosts were searched for the presence of bats by two observers, which recorded all individuals seen. The time spent in each roost varied with the number of bats present and the accessibility conditions.
Species identification were usually made “in situ”, with the aid of head-torches, binoculars and field guides. All bats were photographed whenever possible, not only to build a photographic database, but also to allow a “a posteriori” identification of individuals that raised doubts, or to count large groups that could not be accurately counted in a suitable time in the field. All individuals were assigned to one of the following groups: flying (ie., active), non-flying (inactive) mixed (composed of both flying and non-flying individuals).