Yellow-bellied or White-rumped Sheathtail Bat (Saccolaimus flaviventris)Terry Reardon photograph

What do they look like? Large, microchiropteran (insect eating) bat. In flight, the wingspan looks about 35 cm across. Around bright lights at night, the yellowish-white belly is sometimes visible as it flies past. Apart from the belly, generally black fur and dark skin on wings. A pretty face, much like a small, smiling dog.

Where do they live? Common across most of the region and northern Australia. They are usually associated with eucalypt woodlands and roost singly, or in small groups, in deep tree hollows. Flies far and wide from roosting trees in nightly forays.

What do they need to live, eat and breed? Yellow-bellied Sheathtail Bats feed on insects which they catch on the wing. Like other microbats, they navigate and hunt by emitting high-pitched sounds and listening for the echo or reflection off objects. This is called echolocation and means they can fly in complete darkness. Megabats like the familiar flying-foxes, rely on sight to navigate, and so cannot safely fly in complete darkness.

When might I see (or hear) them? Unlike other microbats, whose calls are at high frequencies, the Yellow-bellied Sheathtail Bats are one of a handful of Australian bats that emit audible chirps in their echolocation call (a soft repeated chip-chip as they fly overhead). Commonly observed foraging for insects around lights near houses, house-yards or street lights.

What management actions affect this species? Maintaining structural diversity in woodlands, especially retaining hollow bearing trees like eucalypts with long spouts will favour insectivorous bats. Land clearing where large hollow bearing trees are removed is a threat to Yellow-bellied Sheathtail Bats. In areas where hollows are at a premium, competition with native and introduced animals, like possums, parrots, Indian Mynahs and European Honey-bees may pose a threat by reducing the bats’ access to daytime roosts.

How do they benefit the land I manage? Insectivorous bats such as the Yellow-bellied Sheathtail Bat can eat their body weight in insects every night, including pest species such as mosquitoes and many species of crop and fodder pest. Bats are the most numerous mammals in savanna woodlands, though least observed. These high numbers equate to an enormous role in insect regulation. In the United States, the role of insect regulation is being recognised by the agricultural sector and the dollar value of microbat service is estimated to be in the millions.

Similar species: Numerous microbats are a similar size, but none have the obvious pale belly.