Feature Article From a Local Expert
Article & Photography by Grant Webster
Most people would be surprised to know that frogs are one of nature’s greatest success stories. Their small size presents an image of a fragile, vulnerable creature, and we are regularly reminded of their apparent intolerance to human activities and susceptibility to pollution. With some exceptions, this is far from the truth. Frogs have existed for 250 million years – witnessing the first dinosaurs, and outliving the last. They successfully competed with the early, small mammals, whose own survival story would in time become ours too. Even today, billions of humans are changing our Earth more rapidly than many natural ecosystems can keep up with. But Earth has always been a place of change and growth.
People share our home with more than 7,000 species of frogs, which survive even the harshest climates – the Arctic tundra; the driest deserts; and everything in between. Antarctica is the only frogless continent, at least now… 65 million years ago Antarctica was a ‘stepping (?hopping) stone’ from South America to Australia. Sensically so, the closest relatives to most of Australia’s 250+ frog
species live in the Amazon, the Andes, and cloud forests of Central America. In fact, all frog species in Killabakh, and even New South Wales, are Gondwanan in origin. Other than the Cane Toad, the only other frogs to settle in (northern) Australia are some recent migrants of Asian origin, crossing land bridges from New Guinea when sea levels were lower.
The mid-north coast boasts about 40 frog species, with 20─30 species common for most localities in the region. By the end of my first year in Killabakh the frog list tallied 21 species: 18 from Killabakh ‘proper’; and three extras from the mountainous rainforests of Killabakh Nature Reserve. I suspect a few more are lurking around… just past Yarratt Forest I’ve found another two species at my sister’s Lansdowne property… good odds they’ll also be nestled into one of Killabakh’s hidden hollows or gullies.
No doubt, most Killabakhians will have heard, and seen, frogs around their house (on windows!?), by the dam, along the creek, crossing a road, in your pool, or tenants of the veranda’s hanging pots – I could go on..
If you’ve ever found a moment to escape the driving monotony of modern routine and responsibilities, you may have been fortunate enough to notice our amphibious friends a bit more closely. It’s easy to recognise the different sounds frog species make – each has its own unique call. Sometimes we see small frogs, sometimes big ones. Some are green, some are brown, some living in drainpipes, others under pot plants. Maybe you’ve even noticed the frogs calling along Killabakh Creek sound different to the ones in the dam? Most people will know they’re louder after rain, and quieter over winter. None of this is random, frogs’ behaviour results from beneficial adaptions and niches, fine-tuned generation by generation; for millions of years.
Have you ever wondered – what are the frogs I’ve seen around Killabakh? what frog makes that sound I hear? or why are they louder on some nights? Within Killabakh, the size, location, and type of property, mean some species are more likely present than others. The 18 local species represent four distinct ‘groups’ of frogs (scientifically, different families – Pelodryadidae, Limnodynastidae, Myobatrachidae, and ‘Mixophyidae’). Species within each group are similar to each other, but differ between groups. All tree frogs belong to Pelodryadidae, while the other groups are terrestrial frogs. The large ground frogs (length 5cm+) are Limnodynastidae, the small ground frogs (length 2-3cm) are Myobatrachidae. The last group is the genus Mixophyes, found along rivers and creeks, often in rainforest, they are among the largest frogs in Australia (10cm+).
Most Killabakhian frogs are from Pelodryadidae (11 species), the misnomered ‘tree’ frogs. Not all can climb, and some live on the ground. However, all have enlarged, suction-cup, finger tips (‘toe pads’) that enable climbing in arboreal species. The Dwarf Tree Frog (Litoria fallax) is the most prolific species across Killabakh, though preferring grasses, sedges, and reeds, this small (~2.5cm) frog is green or brown with its high pitched ‘wreeeek-ip-ip’ call heard from almost any farm dam. It’s also common around household gardens.
Common tree frogs around dams include the Peron’s Tree Frog (Litoria peronii) and Tyler’s Tree Frog (L. tyleri), they’re larger (~7cm), make laughing calls, a rolling ‘dahahahahaha’, and a static ‘ah-ah-ah-ah’. Three ground dwelling ‘tree’ frogs also prefer dams; the Striped Rocket Frog (L. nasuta) and Brown Rocket Frog (L. latopalmata), both are good jumpers, and make fast-paced quacking sounds. While the melodic whistles of the smaller Whistling Tree Frog (L. verreauxii) are heard during winter. Some tree frogs favour temporary pools or ponds instead; the Green Tree Frog (L. caerulea) echoes a deep ‘rawk rawk rawk’ (often from drainpipes!); Dainty Tree Frog (L. gracilenta) groans ‘waaaaaahhh’ after heavy rain; and Bleating Tree Frog (L. dentata) makes an extremely loud ‘ehhhhhh’, on repeat.
Most of the ground frogs also inhabit farm dams, but will occupy other still water sources. The seldom seen Myobatrachidae species include the Dusky Toadlet (Uperoleia fusca), its short ‘irrrrk’ is heard following rain. Almost year-round, the abundant Common Froglet (Crinia signifera), persistently calls ‘crik-crik-crik’. The Red-backed Toadlet (Pseudophryne coriacea) does things differently, its ‘errrh-ek’ call emanates from damp leaf litter along temporary pooling gullies – pinpointing the terrestrial nesting site where the dedicated father guards the eggs until they are hatched by rain runoff.
The conspicuous Limnodynastidae are frogs we frequently encounter, commonly in gardens, colonising any ‘frog pond’ – with foamy floating egg masses, and large dark tadpoles. A sound familiar to many, ‘tok’: the Striped Marsh Frog (Limodynastes peronii) thrives everywhere. Less frequently, from flooded grassland, the Spotted Marsh Frog (L. tasmaniensis) convincingly imitates the sound of machine gun firing. While the Tusked Frog (Adelotus brevis) is equally at home in garden ponds, or a still pool along Killabakh Creek, listen for a soft ‘dih-duk’.
Killabakh Creek provides habitat for three more species; stream dwellers whose tadpoles are adapted to flowing water. You’ll likely find the small Leaf-green Tree Frog (Litoria phyllochroa), common where vegetation grows on banks (especially Lomandra plants), chattering ‘eh-eh-ehhh’ by night. The larger (6-10cm) Stony Creek Frog (L. wilcoxii) prefers sections of cobble stones, its soft babbling call is almost inaudible, but the vibrant yellow coloured males are hard to miss! Finally, Great Barred Frogs (Mixophyes fasciolatus), though locally rare, their massive tadpoles, and deep, harsh ‘waark’ call, indicate they’re around. Their blotchy brown skin camouflages perfectly amongst leaf litter – finding one is not easy!
Now you’re up to date on our froggy friends! So; listen carefully, look closely (night is best…), find time to explore your local creek, dam, or wetland, and get familiar with the lesser known Killabakhians.
Happy frogging!
Grant Webster
