Serpentine National Park is located at the foot of the Darling Scarp, just east of Perth. The Serpentine River that runs down the slopes has carved out a valley of polished granite that ends at the well-known Serpentine Falls. The waterfall is not very impressive (especially during the dry season) and by itself does not warrant the fairly steep park entry fees (AUD12 per car), but I feel that the park and the trails around the waterfall definitely do. There have been some fatal accidents over the years however, when people have attempted to jump from the waterfall, so following suit is definitely not advised.
The Kitty’s Gorge walk has quite a variety of terrain: beginning at a waterfall and hiking up and along the river, cutting in and out of dirt roads and walking trails, swooping around on the hills above the gorge before descending right down into the gorge itself. When it rains, the rapids of the river are apparently quite impressive. Too bad we went during dry season! I guess that explains why it has been named as one of Western Australia's Top Trails by the Trails WA website.
As the dirt road makes its way northward, it eventually reaches a tiny cottage called 'Spencer's mud cottage'. What is interesting about this cottage is not the cottage itself, but the majestic monarch butterflies (Danaus plexippus) that flutter around the area. Monarch butterflies play an essential role in the ecosystem, as do most pollinators. Monarch caterpillars however, are able to eat nothing but the leaves of the milkweed plant, a plant that surrounds the area. The caterpillars' diet helps to protect them from predators such as birds or small mammals. This is because some of the compounds in the milkweed plant (that are then passed on to the caterpillars) make it toxic for most animals to eat. But because a lot of farmers view this plant as a weed, and due to the prevalence of 'Roundup Ready Crops', the numbers of milkweed plants have dropped significantly, which in turn has drastically affected populations of monarchs.
The stages of metamorphoses of the monarch butterfly is fairly drawn-out. The caterpillar itself molts its skin up to five times before beginning the pupa stage, each stage referred to as an 'instar'. During the fifth instar, before it moults its skin for the fifth (and last) time, the caterpillar spins some silk for it to hang from. The pupa skin then hardens and protects the (yet to emerge) butterfly inside. These caterpillars are voracious eaters, and are capable of consuming an entire leaf in less than five minutes. The caterpillars have even been known to occasionally eat their own molted skin!
Another voracious eater that can be found on the milkweed plant are the milkweed aphids (Aphis nerii), otherwise known as plant lice. Aphids are sap-sucking insects that are known to be one of the most destructive insect 'pests' due to the damage that they cause by their sheer numbers.
After you pass the cottage, approximately 3km in, the trail veers left towards a bridge that crosses the river. The old bridge lies upstream just beyond, its skeletal structure still standing, very close to where the Gooraloop Brook merges with Serpentine River.
The jarrah forest (Eucalyptus marginata) begins to close in as you make your way uphill from here. Stay left and you will eventually meet another dirt road (Selkirk Road) that continues northward, making its way uphill onto the upper slopes of the river bank of Gooralong Brook.
The road eventually loops around and heads eastwards instead, roughly a kilometre after the river crossing, and follows an old forestry road that traces the contours of the hill. The trail makes its way along the hilltop, gradually bending north-east, until descending sharply back down to Gooralong Brook at the 7km mark. It is basically downhill from there.
Along the hill we passed by quite a lot of banksia trees (Banksia sp.), with their strange-looking seed pods pointing in every which way. These seed pods have always fascinated me, but I'll leave it to David Attenborough to tell you why:
"Like the bottlebrush, some banksias will not shed their seeds unless there is a fire. Indeed, it is almost impossible to remove them from the plant because they are held in hard woody two-valved capsules. But as the flames scorch the branches, the intense heat causes the capsules to open. Their front ends resemble pairs of brown lips on the side of the furry spike…By releasing their seeds only in the wake of a fire, the banksias ensure that they will fall on well-cleaned, brightly-lit ground recently fertilised with ash and so get the most favourable of starts in what is, even at best, an extremely harsh and demanding environment."
Descending down to Gooralong Brook brings you to a junction of sorts. Following the signs to Kitty's Gorge trail will loop you back in a south-westerly direction and down the gorge itself. The opposite direction however, will bring you to the much shorter 'Stacey's Trail' loop and the historic town of Jarrahdale just beyond that.
The gorge follows the river gently downwards past huge granite formations and rocky outcrops that are fringed by jarrah trees. As you continue walking down the gorge, you are met with some impressive views as the Gooralong Brook and its cascades (after periods of rain at least) are sent plunging down and over granite boulders, smoothening and polishing them over the many years.
The trail eventually swings southward and meets up with the dirt road (Selkirk Road) that you left a while back, and shortly after, the bridge that crosses Serpentine River and the familiar mud cottage just after. From there it is just a short walk downhill back to where it all began.