Tuesday, 17 March 2015

A Blog on Some Frogs.

The Naked Treefrog is often a light cream colour that camouflages it against dried grass and dead wood.

With South-east Queensland enduring such a warm and wet summer this year, people have been quick to notice the inevitable insect population boom that has arisen from these conditions. It seems that every week, there are news reports and press releases on mosquito issues and butterfly swarms, and social media is buzzing with complaints about ants and cockroaches inside houses. What has gone unremarked, however, is that this surge in insect numbers and wet weather has been great for another kind of animal around Brisbane: frogs!

Since September last year, I have had the pleasure of getting to know (for the first time in some instances) quite a few local frog species, some of which I present to you here.

Green Treefrog (Litoria caerulea)

On excessively hot evenings, Green Treefrogs seem to enjoy perching on cool metal objects such as this fence railing.

This iconic Australian animal is well-loved and well-represented around South-east Queensland. I've found Chelsea Street Environmental Reserve in Kippa-Ring to be an exceptionally good place to spot them in an evening, but they are even seen wandering the streets of inner Brisbane suburbs on rainy summer nights. They are long-lived creatures, occasionally reaching a ripe old age of 16 years in the wild and longer in captivity. Where breeding is concerned however, I find them to be fussy regarding water quality, though not location. They avoid polluted ditches, algae-rich ponds and some farm dams, but will happily lay eggs in buckets, old bathtubs and drains of pure rain water. As our expanding suburbs impact local water quality in a negative way, these 'old-timers' breed less and less, and so are declining in some areas. Breeding call: a low, excitable croaking.

Great Barred Frogs have been recorded from Brisbane locations
such as Mt Coot-tha and Tingalpa.
Great Barred Frog (Mixophyes fasciolatus)
Including this frog is cheating a little bit: I actually saw it while camping in New South Wales, at the foot of Mount Warning. It does live in Queensland however, in similar dense forest habitat with an abundance of leaf litter. The strange angles, stripes and colouring of this frog are intended to make it resemble dried leaves, and this first wild encounter with one had me in awe of its unusual beauty. It is a large predator of the rainforest floor; giant tadpoles spotted by bushwalkers along mountain creeks also belong to this species. Breeding call: deep, consistent 'wark, wark, wark, wark...' Almost crow-like.

Though very loud, the tiny Beeping Froglet is impossibly
hard to actually see! Photo by Harry B Hines.
Beeping Froglet (Crinia parinsignifera)
This tiny little frog is a tough little survivor. It is common around many ponds, dams, lagoons and still waters in South-east Queensland, including sites that are semi-polluted. Occasionally it will call during the day in secluded locations such as Purga Nature Reserve in Ipswich, even through winter. I also recently heard them calling with Eastern Dwarf Tree Frogs (Litoria fallax) another winter caller - on a cool night in Redland Bay. Breeding call: a squelchy, far-carrying 'eep!'

Naked Treefrog (Litoria rubella)
So named because it looks like it has forgotten to wear its green 'frog clothes', the Naked Treefrog is a climbing frog that has adapted to doing so among dead timber. It is regarded as a common species in South-east Queensland, but its small size and good camouflage mean that it is usually only observed when calling. I only noticed the gorgeous little specimen seen at the top of this page when I saw it leaping through swampy grass next to a track on Bribie Island. Officially this species has a distribution that covers the entire northern two-thirds of Australia, including desert areas. Wildly different appearances, habitats and DNA results across this range, however, indicates that there are actually several different species lumped together as Litoria rubella, and our local frog is likely to be separated from this grouping some time in the future. Breeding call: a high-pitched grating, repeated continuously.

Male Striped Marsh Frog, calling from my garden pond.
Striped Marsh Frog (Limnodynastes peronii)
This would be Brisbane's most common ground-dwelling native frog, thanks to its ability to withstand even the most toxic of waterways. I've heard it said by both a local nursery owner and by Brisbane author Tim Low that this species dominates garden ponds by releasing mysterious hormones or toxins which deter other frogs from using the same water. Officially, I've never been able to find anything that backs this assertion up, but my own garden pond has become a marsh frog nirvana where even the resident Cane Toads (Rhinella marina) refuse to breed, let alone the lovely Green Treefrog that dwells in the fig tree above. Still, I don't mind this development at all; late at night when I hear their faint calls from the bottom of the yard, these frogs make me feel connected to the wilderness from within my own home. Breeding call: a short, sharp 'toc!'

Ornate Burrowing Frog (Platyplectrum ornatum)

'Bulging' rather than 'frowning' eyes help distinguish a Burrowing Frog from the Cane Toad,
as well as a lack of protruding venom glands on the sides of the neck.

I encountered this adorable little frog - one of my favourites - in two locations this summer: Chelsea Street Environmental Reserve in Kippa-Ring, and along Bulimba Creek in Mansfield. The common denominator habitat-wise is an abundance of sandy soil that allows this species to practice its burrowing habits in. Despite its chubby appearance, the Ornate Burrowing Frog is an accomplished leaper. This was demonstrated to me by the Mansfield specimen; I had expected it to be as confiding as the Kippa-Ring frog shown here, but I instead learned that photography approach limits are best judged on an individual basis rather than at species level. Breeding call: percussive, nasal 'thunk!'

Striped Rocketfrog (Litoria nasuta)



Like the Beeping Froglet, this was another species that I didn't see this summer, so much as hear. The rocketfrogs are actually members of the Australian treefrog family that have adapted to a terrestrial life. This has involved perfecting the world's best 'long jump'; adults are able to leap two metres in one bound, quadrupling the human Olympic record in comparison to body size. In Brisbane, this species lives in swamps, drains and ditches, with the accompanying video being recorded at Chelsea Street Environmental Reserve. Breeding call: two distinct sounds in the one call: a series of squeaky quacks, followed by a chirping noise.

Stony-creek Frog (Litoria wilcoxii)
Finding this species - another treefrog adapted to life on the ground - was a pleasant surprise for me this summer. I had always assumed it was a frog of the mountain ranges, so to find one in suburban Mansfield alongside Bulimba Creek was unexpected, to say the least. It turns out that these frogs simply require running stream water regardless of elevation, with a preference for rocky sites. The Stony-creek Frog sexes are markedly different during the height of the breeding season, with pale-brown females dwarfing the smaller yellow males. Initially, I found it confusingly similar to the Broad-palmed Rocketfrog (Litoria latopalmata), but noted that the rocketfrog has a pale crescent in front of its eye and a chunky black lateral stripe that completely engulfs the ear disc. Breeding call: a low purring noise that blends in with the sound of running water.

Until 2004, Stony-creek Frogs were thought to be the same species as the southern Litoria lesueurii.

Beeping Froglet photo courtesy of Harry B Hines, Department of Environment and Heritage Protection.


10 comments:

  1. frogs are pretty interesting creatures. toads, too.

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    1. They are indeed! Although we hate toads in Australia because our only species is introduced and poisons native animals.

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  2. very informative post about the frogs you have and great photos of them. My family in Innisfail, Queensland had a Green frog living in their outside toilet. but they also had a poisonous frog, the name at present escapes me, found round their property and often was in the swimming pool in the morning. Ah I remember now, it was the Cane Toad.

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    1. Thanks Margaret, yes a green treefrog in the 'dunny' is a classic Australian scenario! Up in north QLD it might have been a White-lipped Treefrog, which is big and green with a white lip (obviously). Cane Toads are a problem all down the QLD coast - I saw plenty this summer but elected to leave them out of this feature! :)

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  3. Lovely post Christian. We consider ourselves lucky to have the Green Tree Frogs and the Striped Marsh Frogs visit us regularly. We also get Dainty Green Tree Frogs (Graceful Tree Frogs) as well.

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    1. Thank you. Come to think of it, I haven't seen or heard Graceful Treefrogs myself this summer. Not sure if that means anything, but I've usually considered them common!

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  4. Your frogs are far more interesting than ours!

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    1. I will admit there's an interesting assortment here!

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  5. Is progress being made to eliminate the Cane Toad or is that pretty much futile at this stage?

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    1. It's pretty futile unfortunately. They are so numerous in the lowlands after a wet summer this year. There's literally one every four or five metres along bush tracks at night. I read that apparently there's an interest in them as a Chinese medicinal export item, but that kind of story surfaces every few years and goes nowhere.

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