“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