Pronunciation: Sood-off-fry-nee, aust,trah-lis
The Red-crowned Toadlet is one of the most characteristic frog species of sandstone areas in the Sydney basin. The red crown it wears is coloured similarly to the iron-stained sandstone boulders that it calls home, marking it king of the sandstone throne. These peculiar frogs have a different mating system to most frogs. Males will make a nest in moist leaf litter and call for females to visit. After mating with several females over a period of time, the male will have accumalated eggs of various ages. The tadpoles in the eggs need to develop to a certain size before they can emerge. When rain comes and washes all the eggs into tributary, only the tadpoles which have grown to the appropriate size to hatch will survive. Scientist call this ecological strategy ‘bet-hedging’, where the frog will have a given chance for a few to survive instead of going ‘all in’. This is an adaption to dealing with the bipolar and unpredictable weather patterns of Sydney.
The call of the Red-crowned Toadlet can be heard below:
How to attract them to your backyard
Red-crowned Toadlet populations are usually removed from areas when there is local urban development. This is due to the toadlets reliance on obscure habitat needs in comparison to most other frogs (as discussed below). This has limited the Red-crowned Toadlet to mainly nature reserves and National Park. There are populations through Lane Cove National Park and even a few scattered populations behind Taronga Zoo in Sydney Harbour National Park. In the Sutherland Shire, there are a few populations around Menai, Barden Ridge and Alfords Point which are situated relatively close to suburban housing, but majority of these toadlets are dispersed throughout Heathcote, Waterfall and the Royal National Park.
A tentative rule of thumb with these frogs in urban areas is: if the housing has been built on the top of a ridge, Red-crowned Toadlets chance of surviving next to these houses drops. This is because this frog species relies on slow flowing tributaries, which have enough water flow to carry debris such as leaf litter and twigs to form clumps in the tributary. It is these clumps which the Red-crowned Toadlets favorably nest in. Urban development set on top of a ridge will often cause larger resurgences of water to flow in these tributaries, due to pavement and guttering, which will wash away the desired habitat of the toadlets.
If you live next to or inside unperturbed sandstone bushland then you may be able to sustain a population of Red-crowned Toadlets in your backyard. However, this is dependent on the specific geological and vegetation characteristics of your property. As mentioned before, Red-crowned Toadlets are very picky and a simple pond will not do.
Trickles and Seepages: Ensure to keep or create a flowing water system that has a low water volume flow. Flows which are too high will wash Red-crowned Toadlet nests away before they have a chance to develop.
Leaf Litter: Leaf litter is very important for Red-crowned Toadlets. This is where they shelter, hunt for food and make their nests. It would be optimum to let leaf litter accumulate in and around any trickles or streams to promote Red-crowned Toadlet nest building. Most leaves from Eucalyptus species are suitable, as are Casuarina and Allocasuarina. They will also nest in bog loving sedge plants.
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Daly G, Owers B and Horton A (2015) The distribution of the Red-crowned Toadlet Pseudophryne australis in the Nepean-Burragorang region of the Sydney Basin. Australian Zoologist 37(4), 535-540.
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Thumm K and Mahony MJ (2002) Evidence for continuous iteroparity in a temperate-zone frog, the Red-crowned Toadlet, Pseudophryne australis (Anura: Myobatrachidae). Australian Journal of Zoology 50(2), 151-167.
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White AW and Burgin S (2004) Current status and future prospects of reptiles and frogs in Sydney’s urban-impacted bushland reserves. Pages 109-123 in D. Lunney and S Burgin, editors. Urban Wildlife: more than meets the eye. Royal Zoological Society of New South Wales, Sydney, Australia.