Creatures of the night

One morning in autumn I heard a distinctive rustling on the bark of a box eucalypt in front of me. I looked closely and saw small animals moving up and down the trunk. I knew immediately that they were sugar gliders.

Excited enough to run home to tell my wife and friends, I would soon find that that morning was the beginning of a long relationship with these beautiful marsupials. Small, nocturnal and arboreal, these gliders are rarely seen by us day-dwelling, ground-hugging humans. I soon learnt that to see them, you must use your ears. You listen for their oh-so-fine treetop movements and for their subtle calls. You also have to be confident enough to walk in the dark across timber-strewn, uneven ground without looking at your feet. But most of all, you have to be patient.

That first tree was one where the gliders had excavated with their teeth a small wound from which they licked sap. Sap, along with gum, nectar and insects, form the diet of these animals. So I had found a food source, but where were the gliders living?

Gradually, by watching and listening carefully over successive dawns, I was able to follow the group as they glided back to their hollow tree where they slept through the daylight hours. Having found that tree, I could then go at dusk and watch the gliders sleepily emerge, have a scratch, and leap off into the dark, with gliding membrane outstretched like a black square against the stars or moon.

My experience is that gliders show no fear of humans - indicating, not surprisingly, that they encounter very few of them. Several times I've had gliders glide right past me at head height or land on trees only half a metre away from my face. I'm waiting for the time when one will actually land right on my face!

Finding new colonies was sometimes assisted by one of the gliders' main enemies: owls. The distinctive two-note calls of boobook owls will be known by many Canberra readers. One dawn I watched as an owl harassed a glider repeatedly as it tried to make its way back to an as yet unknown tree hollow. I lost sight of the glider but followed the more visible owl. It led me all the way to a new glider community hollow.

Owls win some of these contests. Recently when walking in Namadgi National Park I found the back half of a sugar glider that had been discarded by an owl who had presumably been satisfied with the front end. Nature is brutal as well as beautiful.

I've seen lots of owls on Mount Ainslie while maintaining night vigils for gliders, and I've also seen some interesting things among the possum fraternity. Canberrans are no strangers to possums - it's my belief that there's as many brushtail possums in urban Canberra as in the bushland, so well have they adapted to the suburbs.

In the bush you see them in their true habitat. At one particular tree I'd watch in the dawn light as the resident brushtail came home and squeezed into the tightest hollow imaginable. It was a hilarious sight, with back legs and tail hanging out as the animal dragged itself inside.

At another spot one night I was amazed to see a ringtail possum emerge from a tree hollow only to be followed a few moments later by a brushtail. That the two species would co-habit was certainly new to me. Brushtails are feisty critters yet here there was amity.

Females don't have an easy time of it. They carry the young on their backs and do a sterling job of maintaining balance on swaying tree limbs with a rolling young one clinging on for dear life.

Woe betide a possum that gets home late of a morning. Once I witnessed a family of choughs gang up on a hapless ringtail that had been caught in the trees. The birds certainly gave it a seeing-to.

One of the most beautifully camouflaged night creatures that can be seen sleeping by day is the tawny frogmouth. These avian hunters are almost impossible to see even in broad daylight. You have to look twice or three times before distinguishing them from the branches on which they are sitting. Their markings are incredibly fine. Over the years my wife Steph and I have been following the fortunes of several pairs and it is always lovely to see them. Sometimes they sleepily open one eye to scan us, then, deciding we are harmless, they withdraw into somnolence once more. Their low, repetitive, booming call is another that can be heard from Canberra's bushland at night.

Owlet-nightjars are smaller night birds whose harsh call contrasts with the owls and frogmouths.

Species of bats, too, add to the wealth of our night bushland. At dusk they can be seen against setting sunlight, zooming for insects as they home in, using sonar systems.

And so, dawn arrives. In Civic, the clatter of empty beer bottles in the gutter marks the close of another night. But up in the Mount Ainslie bushland, kookaburras laugh a welcome to the rising sun. Gliders, owls and the other dwellers of the darkness head to their respective homes. The nightlife ends and once more the day creatures prepare for their shift. Nature's millennia-old rhythms continue and, for those of us aware of these things, our lives are made richer by them.

■ Matthew Higgins has made two short films about sugar gliders. Both have been screened nationally in the CSIRO Scinema Science Film Festival and one was also a finalist in the Snowyfest Film Festival at Thredbo.