As I type this, a crowd of summer visitors is moving down the coast from the north. Based on past years, they will soon be leaving the seaside and flying up the escarpment to spend the warmer months in Canberra.

October is when they usually arrive, and their choice of accommodation is alongside the lake in the very centre of Canberra – at Regatta Point in Commonwealth Park, in fact.

These Grey-headed Fruit Bats are now an established part of the Canberra summer scene.

(The term ‘flying fox’ is often used, but I don’t think that this tells us anything useful about the bats, and in Australia ‘fox’ generally has a negative connotation, so I’ll stick with ‘fruit bat’. There are no rules here that need to be followed, though.)

The odd fruit bat had turned up in Canberra for a long time, but this arrival of a substantial cohort first occurred in 2003 at the height of the ferocious Millennial Drought, when bat food resources – nectar and fruit – were in short supply. Another driving force was the spread south of another large and numerous bat, the Black Fruit Bat, which in past decades has extended its range south from central Queensland to Sydney, competing with the Grey-headed and, in turn, pushing them further south as well.

Numbers at the Regatta Point colony have fluctuated over the years, but overall, they have been growing; in a good year, there are over 10,000 big bats in the trees near the sound stage.

Bats have had bad press over the centuries for no evident reason, but they are truly amazing animals. Put simply, they are divided into two major groups: the more numerous and mostly small insect-eating bats, which catch their prey on the wing at night using sophisticated sonar, and the big fruit bats.

A small section of the Regatta Point Grey-headed Fruit Bat colony hanging upside-down, wrapped in their wings. Photo: Ian Fraser.

They are the only mammals that have learnt to truly fly (as opposed to gliding) and they do so on enormous leathery wings of thin skin, stretched over four enormously lengthened fingers. During the day, they wrap themselves in the wings like a cloak and sleep upside down, sometimes in huge colonies.

Actually, ‘sleep’ doesn’t really describe a daytime fruit bat colony, which is always restless, with neighbours constantly having loud and often seemingly angry exchanges. There is always something going on, always some bats in the air looking for another perch – a fruit bat roost is a source of endless fascination.

At Regatta Point, there are often youngsters these days, too, as the pregnant mothers give birth soon after arriving. For the first month, the baby clings to her fur, hanging on with teeth and claws as she makes her nightly journey in search of food. Later, the baby is too big to carry and is left in a creche within the colony until she returns in the morning. During the day, she enfolds the youngster in her wings as she rests.

Grey-headed Fruit Bat mother and baby having a rare quiet moment at the Regatta Point colony. Photo: Ian Fraser.

Fruit bats are powerful flyers and can easily cover up to 50 km in a night in search of food. This means that they are of immense ecological importance. They can carry pollen between distant stands of flowering paperbarks or eucalypts, and fruit (and thus seeds) between isolated rainforest patches, keeping the patches healthy and connected. Strictly speaking, these bats don’t generally eat fruit (except for small berries); instead, they drink the juice. They’ll carry a fleshy fruit for some kilometres, crushing it in their mouths and swallowing the nutritious juice, then dropping the skin, pith and seeds.

One serious hazard for fruit bats is loose netting with mesh greater than 5 mm on fruit trees; ACT Wildlife (a community volunteer organisation) rescues and rehabilitates fruit bats entangled in this way.

If you still have such netting, you can exchange it, free of charge, for safe and legal netting through ACT Wildlife.

We have a big banksia by our balcony, which blooms in late summer and into autumn. When that happens, the bats always find it, and we hear them at night, rustling their wings as they move around and occasionally swearing at another bat if it comes too close.

We’re a mere 10 km from Regatta Point as the bat flies, which is no distance at all for them. I count myself lucky that we can host them.

Ian Fraser is a Canberra naturalist, conservationist and author. He has written on all aspects of natural history, advised the ACT government on biodiversity and published multiple guides to the region’s flora and fauna.