Trees

Eastern Banjo Frog’s call is music to the ears

Tuesday 4 October, 2022
The Frog of the Month for October is the Eastern Banjo Frog (Limnodynastes dumerilii) as part of the Goulburn Broken Catchment Management Authority’s 2022 Year of the Frog community awareness campaign.

The Eastern Banjo Frog is found in the Goulburn Broken Catchment’s grey box grassy woodlands which are a focus of the GB CMA Linking Landscapes and Communities Project that works with landowners, communities, and Traditional Owners to improve this critical habitat. This project is supported by the Goulburn Broken CMA through funding from the Australian Government’s National Landcare Program.

GB CMA Project Officer Janice Mentiplay-Smith said the Eastern Banjo Frog was also known as the southern banjo frog and bull frog, however, the most endearing moniker was the ‘Pobblebonk Frog’.

“It’s one of our larger frogs, measuring up to eight centimetres and has warty skin, which can sometimes confuse it with the introduced Cane Toad, but a cane toad is much larger, at about 15cm,” Ms Mentiplay-Smith said.

‘Pobblebonks are special. In behaviour that’s unusual for a frog, at mating time (August to April) the female develops large flaps of skin called flanges, on the first two fingers, and after mating, lays her eggs in foamy masses that she hides amongst water weeds and rushes.

“Using the flanges on her fingers, she then carries air bubbles from the water’s surface and deposits them into the mass of eggs, to keep them oxygenated. This is a level of parental care not usually seen in the frog-world.”

Ms Mentiplay-Smith said, that as one of nature’s little musicians, the Pobblebonk Frog had refined its call to resonate every few seconds; however, a large gathering of Pobblebonks fills the air with an almost deafening crescendo of ‘bonk bonk bonks’.  Males will go to great lengths to ‘out-call’ their rivals by occupying drainpipes or underground tanks to serve as echo chambers.

Once they hatch, the Pobblebonk tadpoles take their time to metamorphose into frogs; the speed depends upon the temperature. In Victoria, this may take 15 months, however in Tasmania, it will be longer.

The Pobblebonk Frog calls the Grey Box Grassy Woodland region home, amongst Yorta Yorta country. In 2017 Yorta Yorta Elder, teacher and co-compiler of the Yorta Yorta Dictionary, Aunty Sharon Atkinson, taught Lyn Loger and Philippa Schapper from Nathalia a Yorta Yorta language basic course, then guided the development of the children’s story “Po-bonk-l Bunyma Bapalwa Po-bonk Creates a Flood”. The word ‘Po-bonk’ used in the title was newly created in Yorta Yorta by Aunty Sharon. To hear the story visit Yorta Yorta Dictionary | WCC Language Program (wcclp.com.au) and click on the ‘DOWNLOAD LINKS’ box.

“Pobblebonks make a fantastic musical addition to your home garden or farm dam,” Ms Mentiplay-Smith said.

“Avoid using chemicals, as all frogs are sensitive to toxins because they transpire oxygen through their skin. If you build a frog bog or pond, the Pobblebonk will most likely be one of your first residents. Just be sure to keep your pond clear of goldfish and mosquito fish, as these non-native species will eat frog eggs and kill tadpoles. Visit Backyard Buddies backyardbuddies.org.au/habitats/build-a-frog-pond/ to find out more. 

“As with all frogs, don’t move frogs from a different location to your pond or frog bog, as you may unwittingly transport disease such as the Chytrid Fungus which is fatal to frogs and will decimate entire populations of all species.”

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Caption: Eastern Banjo (Pobblebonk) Frog. Photo Chris Tzaros