Mount Bold Reservoir (1st May, 2022)

First hike of the City Nature Challenge day three was the recently opened section of Mount Bold Reservoir. Having not visited before I opted for the easy Lookout Trail, but found some time to add a loop around some woodland just East of the carpark.

At the entrance was a Health Alert sign warning that encephalitis causing mosquitoes may be present in the area. Long sleeves, long pants and DEET are recommended.

This accessible Grade 2 walk runs through Eucalyptus woodland with a dense thicket of Golden Wattle (Acacia pycnantha). This being a pioneer species, I assume this area experienced a fire some years back. The high density of this growth is typical, eventually thinning out as the slower growing Eucalypts begin to overtake them. This process is just beginning in the burnt sections of Scott Creek I hiked through recently with a high density of two foot tall Golden Wattles. Scott Creek also had high density areas of Hop Goodenia (Goodenia ovata) and Myrtle Wattle (Acacia myrtifolia), but these were absent here.

High in one of the Eucalypts I heard, then spotted a Western Whistler (Pachycephala fuliginosa). Until recently these were known as South Australian Golden Whistlers (Pachycephala pectoralis fuligens), but a recent genetic study indicates these are morphologically and genetically much closer to birds from SW Western Australia than to Golden Whistlers from eastern Australia and are essentially indistinguishable from western birds. Following naming conventions, the WA Birds and those in SA are now Pachycephala fuliginosa, with a crossover area in South-East SA with the Eastern species Pachycephala pectoralis.

Heading down toward the the lookout the understory biodiversity increases with Spoon-leaf Spyridium (Spyridium spathulatum) becoming common. This is a rare local SA species with patches occurring in Mount Bold, Morialta CP and Deep Creek. (More common on KI). I didn’t expect to find it here. It’s a new species for my Life List and for my CNC observations. Also present was Leafless Bitter-pea (Daviesia brevifolia), a species that puts on an excellent flower show at the right time of year.

The lookout is ideally located with a long view across the reservoir and down to the dam. Afternoon is perhaps a better time to visit to admire the view, when the sun will be lighting up the dam wall.

Near the lookout a Peregrine Falcon (Falco peregrinus) shot out from the trees and began circling around the area directly out from the lookout. Species like this are hard to specifically search for during a bioblitz, but if you spend enough time looking you’ll have many such chance encounters with uncommon species.

To highlight exactly this, walking back along the Lookout Trail I spotted a Robin amongst the Golden Wattles. I took a few photos before realising this was not the common Scarlet Robin seen in the area, but a Red-capped Robin (Petroica goodenovii). Although it’s not unheard of to spot one here, or other locations in the Adelaide Hills, this species tends to live in more arid regions. These nearest location where they are frequently sighted is around Monarto.

This walk was quicker than I’d expected so I continued with a short loop to the East of the main carpark. Along the boundary track there were quite a few introduced weed species including South African Daisy (Senecio pterophorus), Boneseed (Osteospermum moniliferum ssp. moniliferum), Olive (Olea europaea), Spear Thistle (Cirsium vulgare), Bridal Creeper (Asparagus asparagoides), Orchard Grass (Dactylis glomerata), a well established Tree Lucern (Chamaecytisus prolifer), and half a dozen Mediterranean Buckthorn (Rhamnus alaternus). In this area I also pickup up a few additional species for the CNC including Australian Dusty Miller (Spyridium parvifolium), Woolly Rice-Flower (Pimelea octophylla) and an Inchman Ant (Myrmecia forficata).

Mount Bold Reservoir

55km2 of natural woodland, creeks, and forestry reserves surrounding the largest reservoir in SA, on the Onkaparinga River. Walking trails open to the public from Razorback Road in 2022. Messmate Stringybark, Pink Gum, and Cup Gum mid woodland over Golden Wattle, Large-leaf Bush Pea, Beaked Hakea, Heath Tea-tree, Slaty Oak-bush, Austral Bracken, Wire Rapier-sedge and Native Cranberry. A significant section of the Northern side of the reservoir was burnt out in the 2021 Cherry Gardens bushfire. Look out for more than 30 Orchid and 9 Sundew species, Southern Brown Bandicoots and Yellow-footed Antechinus, and Peregrine Falcons.

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Mount Bold Reservoir

See the full list of 114 observations covering 56 species on iNaturalist