Western Ringtail Possums of Busselton’s Tuart Forest.

Historically coastal forests haven’t fared well since the colonial settlement of Australia, often providing the basic needs of fuel, construction material and export income. The tuart tree (from Tooart in the local indigenous Noongyar language,) is one such coastal tree growing on coastal limestone 300km from Jurien Bay in the North, South to Busselton in a strip 5-10 kilometres wide.

Most of the habitat of this tree has been cleared for the development of Perth and surrounds but 183 kilometres South of Perth adjacent to the coastal city of Busselton there remains an impressive tuart forest. This 2000 hectare forest is known as Tuart Forest National Park (N.P.) and contains some epic trees 35m in height, 10m and girth and 2m in diameter. A great way to experience the forest is to drive the 15 kilometre Ludlow Tuart Forest Tourist Drive though the heart of the tuarts.

Tuart Drive winds through the Forest.

In additon to impressive trees Tuart Forest N.P. is special for another reason. It contains the largest remaining wild population of the Western Ringtail Possum, a critically endangered marsupial endemic to the South West of Western Australia. Western Ringtails are however not the only inhabitants of this magical forest, there is a whole suite of wildlife waiting to be discovered in the tuart forest, and the perfect way to discover these inhabitants is to spotlight the aptly named Possum Trail at night.

The Possum Spotlight Trail is a self-guided 1.2 kilometre trail. The refective markers positioned along the trail are illuminated in a torch beam and are easy to follow in either direction. Driving from the Bussell Highway the trail is situated on the opposite side of Layman Road on the approach to Wonnerup House, although unfortunately the trail itself is not signposted from the road and can be easily missed. At the start of the Possum Trail there is a shelter with good information on the history and inhabitants of the forest, including the two possums that can be found spotlighting.

Information Shelter at the beginning of the Possum Trail Walk.

Of the two possum species commonly encountered on the spotlighting trail, the Western Ringtail Possum is in higher numbers, and often upwards of ten possums can be seen on a loop of the trail. The Western Ringtail Possum is identified by dark brown fur (white underneath,) small rounded ears and a prehensile white-tipped tail. It is smaller than the larger Brushtail Possum, and fully grown adults weigh in at around 1 kilogram. Although mostly silent their vocalization is a soft high pitched chirruping twitter, an enchanting and soothing sound when spotlighting the forest at night.

Western Ringtail Possum.

The range of the Western Ringtail Possum included Perth’s Southern and Eastern suburbs in the 1950’s and as recently as the 1970’s they were found in the wheatbelt reserves of Tutanning and Dryandra. Their range has since contracted to the wetter Southwest corner of the state, the victim of a drying climate. Unfortunately this Southwest corner is currently experiencing a population explosion and the associated urban development.

The tuart forest is excellent habitat for the Western Ringtail Possum because firstly, the forest understory is of peppermint (Agonis flexuosa) which consists of 79% to 100% of the Ringtails diet. Secondly the mature tuart tree hollows provide shelter for the possums. Where the possums occur in nearby peppermint wooodland without tuarts they builds dreys (made of shredded bark, leaves and twigs,) in which to shelter.

Peppermints are not the only plant species important for Western Ringtails, they also utilise acacias, melaleucas and banksias (especially the Bull Banksia,) as habitat, for travel routes and to build nests.

Western Ringtail Possum seen in Melaleuca at Tuart Forest N.P.

The scientific name of the Western Ringtail Possum is Pseudocheirus occidentalis which translates as the Western false hand. This is from the greek pseudes – false, keirus – hand, while occidentalis describes the Western location of this species, as opposed to the Common Ringtail Possum of the Eastern seaboard, found all the way from Cape York Peninsula in Queensland down to the forest of Tasmania. The photo below demostrates wonderfully the false hand of two digits opposing three.

The Western False Hand.

Western Ringtail Possums are not exclusively found associated with peppermint woodland. They can also be found in forest blocks further inland, where peppermint trees are present but are not the dominant species, such as Jarrah-marri forest at Perup and karri-marri forest within the Porongurup Range.

There are marri trees on the fringes of the tuart forest and Western Ringtails in common with other arboreal mammals find their Autumnal blooms a welcome addition to their diet. Driving out of the tuart forest on Layman Road after a spotlight during February, I startled at Ringtail feeding on marri blossum which fell from a tree overhanging the road.

Horrified I slammed on the brakes and pulled over. I could see the possum sitting on the road in the red light of my rear lights. Fortunately the road was quiet at this late hour, and so I promptly approached the possum to check for any obvious injuries from the 8m fall.

Apart from being obviously dazed it seemed ok so I quickly gathered it up in my jumper and placed it in a peppermint next to the road. Still obviously dazed it considered me for a while before much to my relief it clambered up into the canopy none the worse for wear!

Western Ringtail Possum on the road.

The second possum found in the tuart forest is the ubiquitous Brushtail Possum (Trichosurus vupecula,) which translates as bushy-tailed fox-face. These possums are larger than the Western Ringtail Possum and have grey fur and a bushy tail. They are by far the bolder of the two possums species, and during the April mating season their screeches and hisses echo throughout the forest.

The tuart forest is reputed to contaian the highest density of Brushtail Possums in the state and they are often seen on the Possum Trail, although not usually in as higher number as the Ringtails. They are often encountered foraging on the forest floor.

Common Brushtail Possum.

Not all of the Brushtail Possums of the tuart forest are the typical grey colour, there is also a variant with black fur that at first glance can look like a Ringtail until the other distinguishing features are taken into account.

Brushtail Possum (black fur variant.)

The possums are not the only inhabitants of the forest and frogs are often encountered on the Possum Trail at night. The most common species seen by far is the Motorbike Frog, especially after showers in the wetter months of the year. These frogs of the tree frog family Litoria are often found climbing in low vegetation rather than on the forest floor.

Motorbike Frogs.

Moaning Frogs are a frog of the burrowing frog family Heleioporous, and are most commonly seen in the tuart forest during the Autumn months when they are found on the surface looking for mates. The males of this species build burrows in low lying areas that are inundated by water, and in Autumn will call from the entrance to these burrows to advertise for a female. Part of the Possum Trail passes adjacent to the Wonnerup Wetlands and the haunting choir of Moaning Frogs calling from the wetlands is a sound to behold!

Moaning Frog.

The final species of frog I have found on the Possum Trail is the Western Banjo Frog. This large frog often exquisitely patterned frog is identified by a dorsal stripe running the length of the back. It is a frog associated with wetlands and permanant water and accordingly is found on the forest floor where the Possum Trail passes Wonnerup Wetlands.

Western Banjo Frog.

Beautiful Tawny Frogmouths, the ghosts of the forest, are often seen hunting on the Possum Trail at night, most commonly in the peppermint understory approaching the carpark. This docile bird of the night will often freeze on a branch in an attempt to remain undetected by it’s impressive camouflage demonstrated below as it perches on a litchen covered branch.

Tawny Frogmouth.

If approached a Tawny Frogmouth will not just rely on camouflage, but will often strike a pose to resemble a branch to blend into the forest.

Tawny Frogmouth.

There is an inhabitant of the fallen timber near the carpark that I had often glimpsed ove the years but had never properly sighted. With the aid of the thermal imager I recently discovered this flighty rodent was a Bush Rat, although one with a rather grizzled right ear!

Bush Rat.

When looking for wildlife at night the tuart forest is overlooked by visitors in favour of the jarrah forests of the Darling Scarp and wandoo forests of the Wheatbelt. This a shame because not only does this forest contain a good suite of wildlife but it is a most wonderful forest in which to spend an evening spotlighting.

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