A Focus on Amphibians

I spent Monday night of this week in the Redlands, searching along Hilliards Creek for frogs. Surveying wildlife in this area is not a new thing for me, and some of you may remember that I wrote a feature last year on the fish found in this waterway. I
chose a slightly different location this time, closer to the headwaters of the creek in the Squirrel Glider Conservation Area, off McMillan Road. After my adventures chasing Squirrel Gliders last month, I thought I might be able to have a second chance at photographing these elusive creatures, as well as focus on amphibians.

A daytime stroll through the reserve last week gave me a chance to study the habitat I would be working with. Despite being a tiny reserve, there really is a remarkable array of different woodland types co-existing there, the main three being areas of Eucalyptus, Casuarina and Melaleuca trees. Uniting these sections is the waterway itself, vegetated with African Cape Waterlilies (Nymphaea caerulea) and native Mat-Rush (Lomandra species) grasses.

Hilliards Creek; INSET: Swamp woodland

In daylight hours, Dollarbirds (Eurystomus orientalis) and Black-faced Cuckoo-shrikes (Coracina novaehollandiae) are common birds here. During a brief rain shower, I also heard Graceful Tree Frogs (Litoria gracilenta) calling from up in the trees, though I didn't hear them on my subsequent night visit.

I began my nocturnal walk off the McMillan Road entrance, following the clear trail alongside an area of swamp woodland. Observed immediately was a trusting Tawny Frogmouth (Podargus strigoides), as well as a Common Ringtail Possum (Pseudocheirus peregrinus). It was the frog calls emanating from the grass tussocks that intrigued me the most however, as I did not immediately recognise the species making them.

A bit of investigative work later revealed that I had been in the presence of Copper-backed Broodfrogs (Pseudophryne raveni). These tiny frogs are members of the same genus as the Corroboree Frog, and just like their alpine relatives, they forego a free-swimming tadpole stage in their development. Instead, the male frog excavates a chamber for the large, fluid-filled eggs to reside in, where the tadpoles mature beyond the reach of hungry fish mouths. To prevent the eggs and young from drying out, these types of frogs tend to live in areas that are quite boggy and prone to inundation. 

The most common amphibian in the reserve was, unfortunately, the introduced Cane Toad (Rhinella marina). Introduced from Hawaii in 1935, these monsters have a devastating impact on local wildlife populations thanks to their incredible toxicity. They seem to know they are invulnerable too, hopping boldly along open trackways in full view of any predatory animal, protected by their gigantic neck glands.

Cane Toad

Eastern Dwarf Tree Frog

The toads were also present in the creek waters, making their eerie 'idling motor' breeding call. Fighting to be heard among them was a solitary Striped Marsh Frog (Limnodynastes peroni), uttering a lonely 'toc!' from thick vegetation. Further upstream, male Eastern Dwarf Tree Frogs (Litoria fallax) held their own against the toad invasion, nimbly manoeuvring around floating lilypads as they attempted to attract mates. While frogs are often very cute creatures, their stationary habits mean they are not always that interesting to observe for long periods of time. These little frogs were an exception to this however, and I enjoyed watching their territorial antics play out in front of me. Below is a video snippet recording some of this behaviour - please excuse the shakes and the blurs, as I was quite tired at this point!



Swamp Wallaby

Despite throwing my torch beam up into the Eucalypt and Paperbark boughs, I didn't spot any Squirrel Gliders. The most common marsupial in the reserve was a new one for me though - the Swamp Wallaby (Wallabia bicolor). Previously I have only had brief glimpses of this animal, but the population here seems quite relaxed - note the photographed individual continuing to chew its dinner! Whereas most wallaby species have retreated away from development into the hills and forested valleys, the Swamp Wallaby persists in tiny fragments of suburban bushland. Unfortunately, this also makes it a very common victim of car-strikes, and most road-killed macropods I see in South-east Queensland are of this species. It is quite different to all other kangaroos and wallabies - scientists believe it has evolved along a separate branch of the 'family tree' - so it would be a shame to witness the local extinction of a creature that is still fairly unknown. All the more reason to drive carefully when you are out and about in South-East Queensland, especially at night!