Onkaparinga River RP (29th Apr, 2022)

Second stop on the first City Nature Challenge day was Onkaparinga River Recreation Park. I took a short loop from the Commercial Road entrance, skirting a couple of wetland ponds and along the river’s edge, in the hope of spotting a few estuary birds, in particular the Black Swan.

The section of farmland South of the track was host to feeding Galahs (Eolophus roseicapilla), Long-billed Corellas (Cacatua tenuirostris), and a mob of Western Grey Kangaroos (Macropus fuliginosus) watching the housing development construction on the next field over.

Along so many of the tracks through this park the Southern Meat Ants (Iridomyrmex purpureus) are firmly in charge, heading out from their large distinct nests up and down the walking tracks and clearing tracks through the open grassland. I’m yet to determine if the sheer number of nests is typical of this environment, or whether it is representative of an ecosystem out of balance. Often nests of this species have signs of Echidna raids. But with no Echidna records on iNat or ALA in this park, perhaps their absence allows the Ants to become dominant.

One of the small ponds to the North of the track, with low water levels and muddy banks at this time of year, played host to a dozen or so Galahs (Eolophus roseicapilla) cautiously flying down for a drink.

So much of this section of the park consists of invasive introduced species, mostly commonly Coastal Galenia (Aizoon pubescens) which covers the ground, and Sweet Scabious (Sixalix atropurpurea), interspersed with Horehound (Marrubium vulgare), various Nightshades (Solanum sp.), Onion-Leafed Asphodel (Asphodelus fistulosus), and patches of Fennel (Foeniculum vulgare).

On a low hanging River Redgum branch I spotted a Tube Spittlebug (Family Machaerotidae) nymph tube, similar to the one from Hallett Cove CP earlier in the day. Until today I’d never seen these before, now I’ll likely see them everywhere.

Above the high tide line were both the Short-leaf Bluebush (Maireana brevifolia) and Maireana oppositifolia, with their differing leaf shapes, and an abundance of Nitre Bush (Nitraria billardierei) and Seaberry Saltbush (Rhagodia candolleana).

Taking some time to look a little closer, I spotted a Green-head Ant (Rhytidoponera metallica) amongst a Berry Saltbush, a new Land Snail species for my Life List that unfortunately was the introduced Pointed Snail (Cochlicella acuta), and a Horehound Bug (Agonoscelis rutila), also a new species for my list.

A total of 23 Bird species were recorded, including a few I less frequently sight. A couple of Straw-necked Ibis (Threskiornis spinicollis) feeding in the shallow water, and a Little Egret (Egretta garzetta). Unfortunately, no Black Swans.

Onkaparinga River Recreation Park

Where the Onkaparinga River reaches the plains. 2.6km2 of flood plains and wetlands, Fish breeding grounds and habitat for migratory Birds. Recreation area for walking, kayaking and fishing. Surrounded on all sides by suburbia.

iNaturalist Projects

Onkaparinga River Recreation Park, South Australia

Ferals in South Australian Reserves – Onkaparinga River RP

Birding Hot Spot – Southern Ponds, Onkaparinga River RP

NATUREhoodz Onkaparinga River (Saltfleet Street)

See the full list of 139 observations covering 76 species on iNaturalist