The Bass River Bobucks appearing in The Victorian Naturalist, February 2006 issue! Of course I'm biased but I reckon this is a great shot of a Baby Bobuck! You can ID the species because of its blunt, shovel shaped nose and its rounded ears. The adults, apart from their short round ears, have a very dark, steely grey coat. (Clickable Image - 300K)

In The Gurdies Reserve itself, along the banks of the creek, more Bobucks. And more young. It must be breeding season? This population, far from teetering on the edge of extinction appears to be healthy and vibrant. What's really needed now is for some researcher to try and count them, and also ascertain the limits of their range. After all, an unrecorded population is not something you turn up every day.

You can see how bulky and muscular T. caninus is compared to the lighter built T. vulpecula. The Mountain Possum, T. caninus, is said to be a gentle, peacable animal, one that is amenable to handling by humans. Not at all like the aggressive Brushtail Possum, T. vulpecula, who will bite viciously. Only don't try handling native animals, Questers! For one thing they're all protected by law and for another thing - I'm no expert! For all I know Bobucks may bite like the Furies. Apart from Common Brushtail Possums, I've only ever seen any of these critters as images captured by my cameras. I'm merely a Techno Geek, remember.

There are snakes galore too, wherever there's water and cover nearby. Although cropped a little, this one appears to be a large Brown Snake. You can see it's plump and sleek looking. Doubtless snakes rely on the numerous rodents hereabouts as their main food supply.

We can now document that the banks of the Bass River are a rich haven for our unique native animals. The reason, of course, is that large stands of native vegetation are in place along some sections of the Bass River. Trust For Nature have covenanted part of the only stretch of remnant riparian vegetation on the Bass River, thus permanently protecting a unique habitat for these Bobucks and other native creatures. Want to know more? Visit Trust For Nature!

Our cameras see wombats at last. Although by no means uncommon, wombats are one of the few animals that retire from our electronic eyes in the night. Not sure why this is so.

Echidnas, of course, are present in generous numbers. These little guys shuffle back'n'forth by day and by night. It's curious. You see them any hour, whether by night or during the hottest part of the day. They don't seem to have set waking and resting times like all other animals do. The ancestral line of these Monotremes extends far back in time, before even the dinosaurs. They're so ancient they share physiological characteristics of both mammals and reptiles.

Reptiles, of course, become torpid when their body temperature falls. But do they truly sleep, in the same way that mammals do? The Monotrematas' distant forebears were first off the blocks with homeothermy, but did they ever evolve the art of sleep like later, true mammals? Did homeotherms' high and constant energy consumption require the development of sleep, but poikilotherms' constantly see-sawing metabolic rate did not? If so, then what about an animal that is part reptile, part mammal - half a homeotherm in other words? Would it sleep? 

Possums Everywhere ... The ubiquitous Common Brushtail Possum, Trichosurus vulpecula is also present in generous numbers. Just as they are almost everywhere else! These guys are easily identifiable at close range by the brown stain on their chests that is due to a glandular secretion. This feature is diagnostic as it is absent from T. vulpecula's relative the Bobuck, Trichosurus caninus.

Bobucks Detected on the Bass River!

Aha! We have made first contact with a Bobuck colony outside The Gurdies. This one appears to be young female with a large juvenile upon her back. This shows that The Gurdies Bobucks are not confined to The Gurdies but are dispersed along waterways in this part of Gippsland. Our cameras have, so far, detected no Bobucks in the general forest where live the Common Brushtails. They appear to be entirely confined to creeks and the Bass River. The fact that young are being detected indicates that the population is resident and not immigrant and that it is at least stable.

Perhaps it is even expanding? Yet they have remained uncatalogued from the early 20th centrry until the early 21st century. Until our cameras came along! Of course, I'm hardly an unbiased party to the matter but I reckon this circumstance is quite remarkable.

T. caninus and T. vulpecula ... sharing the neighborhood? Now here's something that's not supposed to happen. Trichosurus vulpecula and Trichosurus caninus share the same territory and presumably the same resources along the Bass River. T. caninus is said to be an aggressive species that will drive its cousin away. It's the cold of the high country that gives T. caninus its selective advantage in its snow-clad mountain reboubt.Yet here the two rivals coexist, on the ground in a mild climate and thus on an equal footing, as it were.  Hmmm ... this is not quite as I thought.

Why is this highly unusual? Dr. Karen Viggers says:

Mountain and Common Brushtail Possums rarely occur together. The Mountain Brushtail is almost never found in dry forests and woodlands--these are the domain of the Common Brushtail Possum--and it appears to exclude the smaller Common Brushtail from wet forest habitats. Strong evidence for habitat exclusion on mainland Australia comes from Tasmania where the Mountain Brushtail is absent and the Common Brushtail occurs in large areas of wet forest, as well as other habitats. 
K. Viggers & D. Lindenmayer, Nature Australia, Spring 2002.

So it seems that here in southwest Gippsland in a coastal environment we have a population of Bobucks which does overlap with their close cousins and arch rivals, the Common Brushtail Possums. These photos prove they share the same habitat, even the same game trails along the forest floor. They must, therefore, come face to face very frequently. Do they compete for the same resources or are their habits different enough to allow peaceful co-existence? We have no idea at this stage. 

Another thing that may pesent problems for The Gurdies Bobucks is a shortage of nesting sites. It seems from Dr Vigger's paper, and from Dr Jenny Martin's more recent work, that Bobucks require hollow trees as nesting and refuge sites.

Den Swapping. Perhaps one of the most extraordinary findings of our work emerged when we radio-collared animals and began studying the way they used large trees with hollows as daytime denning or nesting sites. We followed animals to their nest sites each morning for nearly two years and found that, over a period of a few months, an individual may use more than 25 different hollow-bearing trees! In fact, the 16 radio-collared animals we tracked used more than 110 different hollow trees over the duration of the study.
K. Viggers & D. Lindenmayer, Nature Australia, Spring 2002.

There are dead, hollow trees within The Gurdies but not very many, going by what we've seen. There are some in the Bobucks' Creek and there are a few scattered throughout the Reserve. We have a hunch - and it's only a hunch at this time - that these Bobucks use the reeds in the creek as their principal refuge. If they do, it would represent a departure from their behavioural norms

Bobucks are also remarkably long lived as compared with other animals of similar body size. Apparently they have diverged in this regard from their cousins, Trichosurus vulpecula. Their breeding strategy must confer a selective advantage in living long. This is a feature that could be worthy of further study?

Longevity. One amazing outcome of our trapping work at Cambarville was the rediscovery of a number of animals that had been marked in an earlier study in the late 1970s by Victorian Government ecologists John Seebeck and Bob Warneke. Their field-data books showed that these animals were adults when first marked, making them at least 17 years old when we recaptured them during the 1990s. Also, the animals were trapped in the same places they had been caught well over a decade earlier. These results make the Mountain Brushtail Possum one of the longest-lived and most sedentary species of marsupials. 
K. Viggers & D. Lindenmayer, Nature Australia, Spring 2002.

REFS: 
   The other BRUSHTAIL POSSUM. Karen Viggers, David Lindenmayer, 
   Nature Australia Spring 2002, Vol. 27 Issue 6, p46