Bioacoustics of Saccolaimus flaviventris

Status and Conservation . Classified as Least Concern on TheIUCNRed List. The Yellowbellied Sheath-tailed Bat has a large distribution, uses a variety of habitats, presumably has large and stable overall population, occurs in protected areas, and feces no significant threats. In northern Australia, acoustic surveys using full-spectrum detectors that record harmonic profiles suggest that it is relatively common. The species has reported incidences of viral Australian bat Lyssavirus that can be transmitted to humans. Feral European honeybees {Apis melliferd) commonly take over tree hollows in arid Australia and displace Yellow-bellied Sheath-tailed Bats. Habitat clearing and replacement of perennial tree species in arid areas have reduced area of occupancy. Targeted surveys along southern coast of New Guinea will more clearly define extent of occurrence and habitat associations. Additional ecological research should be targeted in southern parts of its distribution to better understand its apparent migratory behavior and possible use of torpor. The Yellow-bellied Sheath-tailed Bat is rare in south-eastern Australia, where records possibly represent occasional summer-autumn visitors, vagrants, or small resident populations.

Habitat . Tall rainforest and eucalypt forests, mallee woodlands (low-growing bushy eucalypt), and open habitats. The Yellow-bellied Sheath-tailed Bat is relatively abundant in tall eucalypt forests of northern Australia, and its use of gallery forests with old trees in riparian areas probably help it to make nightly foraging trips into surrounding woodlands that lack large trees suitable for roosting. In New Guinea, it has been found only in coastal lowlands below elevations of 100 m; however, this might be due to limited knowledge because it occurs up to 600 m in Australia. Food and Feeding . The Yellow-bellied Sheath-tailed Bat is insectivorous and includes beeties and moths in its diet. It typically uses a fast, direct flight while foraging for aerial insects above eucalypt forests but will fly close to the ground in open areas. Echolocation search calls are audible to humans and emitted via the mouth. Breeding . In Australia, mating occurs in August; females have one young in December-March. Pregnancies are always restricted to the right uterine hom. Subadults are only found inJanuary—February. Activity patterns. The Yellow-bellied Sheath-tailed Bat is crepuscular. It roosts in tree hollows and emerges at dusk to forage; it will temporarily shelter in buildings along migration routes. In Australia, the species often uses abandoned nests of Sugar Gliders (Petaurus breviceps) as roosts. Multiharmonic echolocation calls are of long duration. Harmonic with greatest intensity starts at c.20 kHz and slightly sweeps down to c.18 kHz. Characteristic frequencies are 17-5-22-5 kHz. Search phase is usually curved but can be flat. Harmonics are often 28-33 kHz and less commonly 9-13 kHz. Occasional non-harmonic pulses within a sequence have characteristic frequency as low as 15 kHz or as high as 24 kHz. Movements, Home range and Social organization. Yellow-bellied Sheath-tailed Bats are capable of ranging up to 30 km each night as they forage. They tend to be solitary but will roost in tree hollows in groups of 2-10 individuals, particularly in late winter and spring. Temporary gatherings of breeding groups can exceed 100 individuals. Some individuals make migratory movements in southern parts of its distribution in autumn, although most records from south-eastern Australia are of exhausted individuals found in exposed situations, which might indicate they are vagrants. Seasonal movements might also occur in mid-coastal Western Australian.