“The majority of roost trees are occupied by mixed groups of adults, with territories comprised of a single male and one or more females and their dependent young” & “Dominant individuals (defined as reproducing males and females) occupy the centre of roosts and subdominant individuals (defined as non-reproducing males and females) the outer area”
These historic perspectives also describe complete separation of males and females between September until early December (the period immediately before parturition, during lactation, and before conception) and again post March (after conception) (Nelson 1965a; Nelson 1965b). During these times, animals were historically noted to segregate by tree or height, such that all social contacts were between individuals of the same sex. However, these observations contrast with more recent observations of flying-fox social groupings (Puddicombe 1981; McWilliam 1984; Eby et al. 1999; Welbergen 2005), and observations from this study. In contemporary roosts, mixed-sex groups are commonly present all year around, such that males and females co-occur in the roost and within trees year around.
Historically, during the times that males and females co-occurred within roosts, four types of social groupings were noted: 1) guard groups on the outsides of roosts, 2) family groups of one male, one female and one young, 3) other adult groups including polygamous males, 4) groups of juveniles. More recent observations, and results from this study suggest, however, that there is no clear spatial structure in the distribution of the sexes within the roost. Puddicombe (1981) notes that reproductive groups (mixed groups of males, females and their young) were uniformly distributed through the camp and present in peripheral areas (McWilliam 1984). Additionally, in this study we observed randomly distributed groups of mixed males and females, and groups of males. This potentially reflects the change in occupancy patterns in flying-fox roosts, where aggregative living was historically believed to be driven by strong social drivers (i.e. mating), whereas aggregative living in contemporary roosts is thought to be driven by continuous resource availability in the urban environment (Parry‐Jones & Augee 2001; Williams et al. 2006). The observations will have implications for current management plans. Specifically, in support of current guidelines, managers should avoid management actions during times of the year when females are in late stages of gestation and have dependant young that cannot fly on their own (as per Commonwealth of Australia 2015; Department of Environment and Science 2020a). Importantly (and in contrast to current guidelines), actions scheduled within this time should note that restricting work to edges of roosts will likely not circumvent disturbances to gestating females and dependant young