Over some years I have had a programme “Bird Talk Back” on ABC Far North in Cairns. Yesterday (31/01/2012) I fielded ten calls in thirty minutes. Early in the programme a caller from Walkamin (between Mareeba and Atherton) had found four dead cane toads with an small incision in their throat by her small backyard pond. I told her plainly that it was a good mystery thinking that it would be animal attack rather than bird predation. About three calls later a gent from Gordonvale south of Cairns assured us that he had watched White-tailed Rats and (surprise, surprise!) Northern Brown Bandicoots kill and eat the non-toxic underside parts of cane toads. Minutes later the mystery was solved when George who owned a piggery at Walkamin called in to tell us about Roufous Night Herons. He related that after an early evening storm one time he checked the piggery and that a night heron was moving through the pig pens and systematically flipping cane toads on their back and taking out their innards. Given the shape and dexterity of their pointed bill the night heron would be well able to extract the gut through a small incision. On my next programme I will endeavour to follow the thread on birds and cane toads in an effort to derive some more latent information that is held out there by everyday non-scientific observers.
Del. Richards, Fine Feather Tours, Mossman, NQ. ===============================
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Found all this most fascinating David .. especially after watching on the ABC last night the show titled Cane Toad: The Conquest.
If I heard correctly, the crows were making a tiny hole and extracting the liver. This meant that without the pressure against their diaphragms, the toads kept on inhaling until rupturing, apparently splattering entrails up to a metre away. http://en.wikipedia.org/wiki/Exploding_animal#Toads I’ve heard of Black Butcherbirds ripping toads open down the length of their bellies after flipping them over. Hopefully, these pests will be a welcome major food source for native birds in the future. Cheers,
Tony
Tom,
I saw that episode. The transcript is as follows:
” At a pond in Hamburg, in 2005, toads started exploding during the mating season. Thousands of toads, swollen to three times their usual size, crawled out of the water, making eerie screeching noises, and went pop. Toad entrails were propelled up to a yard away.
The authorities feared toxic pollution, or a new “bird flu” style health emergency, but when the “pond of death” was pumped into tankers and analysed at laboratories, no clue was found. Exploding toads were subsequently reported at other sites in Germany and Denmark.
One theory is that the pond was infected by a fungus or virus, brought in by nearby racehorses. Another is that birds peck the livers from living toads; the toads then puff up, which is their natural defence mechanism against predator attack, and water enters the cavity in their body through the wound, and thus they keep inflating until they pop. (Two years previously, crowds of Hamburg crows had taken to attacking humans en masse, without warning, in a local park.) ”
Cheers,
Carl Clifford
Did anyone see an episode of QI shown a couple of weeks back? Stephen Fry mentioned that there was a story of ‘exploding’ Common Toads (Bufo bufo?) in the UK, at the time no-one knew the cause but it turned out that crows had been doing something similar and ‘extracting’ their organs and in doing so they had induced the amphibians to inflate themselves and explode! (well I think that’s how the story went:-))
Tom
On Wed, Feb 1, 2012 at 10:54 AM, Del Richardswrote:
Did anyone see an episode of QI shown a couple of weeks back? Stephen Fry mentioned that there was a story of ‘exploding’ Common Toads (Bufo bufo?) in the UK, at the time no-one knew the cause but it turned out that crows had been doing something similar and ‘extracting’ their organs and in doing so they had induced the amphibians to inflate themselves and explode! (well I think that’s how the story went:-))
Tom
On Wed, Feb 1, 2012 at 10:54 AM, Del Richardswrote:
Here is some latent information from a birder who previously conducted scientific reasearch on Cane Toads and other frogs in North Qld. The toxic parts of adult Cane Toads are the paratoid glands on the shoulders, the dorsal skin and the ovaries. Quite a number of animals have learnt to eat the non-toxic parts by flipping the toads and chomping through the underbelly. Mostly they eat the internal organs (except the ovaries) and the thigh muscle meat. In Townsville in the 1990s I recorded Aust White Ibis, Black Kites, Australian Ravens and Water Rats doing this regularly. None however, left a tiny hole in the throat, they sliced the belly wide open. All searched for them systematically, apparently following the theory of search pattern behaviour . At one point I had 24 open pens in a cow paddock by a dam, each with a single adult and 10-30 tiny metamorphs (i.e. newly metamorphosed from tadpoles). The adults started mysteriously disappearing after a couple of days. Turned out that a flock of Ravens that had learnt to check the pens at dawn each day, flip and kill the toads and then cache them in trees. The sympatric Torresian Crows showed no interest in the Toads, but the Ravens would defended my pens from their rival Crows all the same. It does not surprise me that Night Herons also eat Cane Toads, and I’m sure many other herons do too. However, I would be surprised if Night Herons did so by making a small incision in the throat. They might be able to get the gut that way, but not the heart or the thigh meat. I’m not sure what would eat them that way, but suspect it might be something capable of crawling inside, a centipede perhaps? Dissecting one of these victims might help. Few things can eat a toad whole. A lot of snakes, goannas and quolls have apparently died trying to do so. The widespread decline of these preadators still puzzles me a little, because the Common Green Tree Frog is just as toxic as the Cane Toad. These predators learn not to eat Green frogs, but often don’t learn to eat toads. Many of your listeners will know that their puppies learn not to eat toads and green frogs alike after only lick of each, but might be sick for a day or two afterwards (and then pretend not to notice frogs for the rest of their lives). The Keelback, a common water snake that specialises in eating frogs, eats the young metamorphs whole, and even seems to prefer them to other frogs, at least sometimes. Meat Ants swarm and devour small toads. Green Tree ants will carry flattened and dried road killed toads in one piece up a tree to their nests in extrodrinary displays of determination. A photo of a Papuan Frogmouth with a frog in its bill was published on the back cover of wingspan maybe 15 years ago, with the suggestion it may have been a Cane Toad, but who knows. In my pens, I observed naive juvenile Pied Butcherbirds trying unsuccessfully to eat my metamorph toads. They would pick them up and fiddle with them in their bills but quickly drop them (alive and unharmed) and try another. I assume the small parcel of edible meat wrapped in poisonous skin is too difficult to process, unlike the adult toads. The question is often asked by frog researchers “why are metamorph Cane Toads diurnal when most other frogs are nocturnal?”. They usually offer answers like the night is too cold or some other reason why metamorphs are unable to be active at night. I would suggest that they are able to be active by day when most other frogs (including adult toads) cannot be, because they have better defence against predatory diurnal birds. Incidently, the tadpoles are very poionous too, and few predators can handle them. This allows them to breed in water with fish, unlike native frogs. A colleague was studying what did and did not eat the tadpoles, but so long ago I can’t recall much. Dragonfly larvae snip the tails off the taddies, which leaves them to die floundering helplessly. David James, in Jakarta burunglaut07@yahoo.com ==============================
________________________________ Sent: Wednesday, 1 February 2012 11:54 AM
Over some years I have had a programme “Bird Talk Back” on ABC Far North in Cairns. Yesterday (31/01/2012) I fielded ten calls in thirty minutes. Early in the programme a caller from Walkamin (between Mareeba and Atherton) had found four dead cane toads with an small incision in their throat by her small backyard pond. I told her plainly that it was a good mystery thinking that it would be animal attack rather than bird predation. About three calls later a gent from Gordonvale south of Cairns assured us that he had watched White-tailed Rats and (surprise, surprise!) Northern Brown Bandicoots kill and eat the non-toxic underside parts of cane toads. Minutes later the mystery was solved when George who owned a piggery at Walkamin called in to tell us about Roufous Night Herons. He related that after an early evening storm one time he checked the piggery and that a night heron was moving through the pig pens and systematically flipping cane toads on their back and taking out their innards. Given the shape and dexterity of their pointed bill the night heron would be well able to extract the gut through a small incision. On my next programme I will endeavour to follow the thread on birds and cane toads in an effort to derive some more latent information that is held out there by everyday non-scientific observers.
Del. Richards, Fine Feather Tours, Mossman, NQ. ===============================
To unsubscribe from this mailing list, send the message: unsubscribe (in the body of the message, with no Subject line)
http://birding-aus.org =============================== ===============================
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