Review of existing empirical support
We conducted a systematic literature search of peer-reviewed published literature using ISI’s Web of Knowledge (July 27th2020). Keywords were chosen to target studies evaluating the within- and between-roost structure of Australian flying-foxes (Table S1). This included any studies relevant to 1) the physical structure of roosts (e.g. area, tree structure, tree/roost selection), 2) the social structure of roosts (e.g. demographic and species structuring), 3) roosting behaviour (e.g territoriality and fidelity of individuals), 4) movement and migration relating to occupancy and abundance of roosts, and 5) roost microclimate. In addition to the literature search, reference lists and relevant studies already known to the authors were also screened to identify potentially relevant studies not captured by our initial search. We also included empirical support from key unpublished sources (e.g. theses).