“Garbage chickens” take on the hated cane toad

A rather unloved Australian bird has taken on the fifth continent’s most hated animal: the cane toad. With great finesse, the ibis has managed to put the poisonous amphibians on the menu – without endangering itself.

An Australian White Ibis (Threskiornis moluccus) on a tree at Herdsman Lake in Perth, Western Australia

Zambezishark / iStockphoto / Getty

The Australian ibis is not very popular in its native country. The white and black bird has adapted to urbanization. His penchant for scavenging leftovers from rubbish bins has earned him the unflattering nickname “Bin Chicken”. Now this fowl has taken up the fight against an even more hated animal on the fifth continent: the cane toad.

Uncontrolled spread

Cane toads originally come from South and Central America. They came to Australia in the 1930s. Back then, farmers wanted to use them to fight the sugar cane beetle, which was causing major crop damage in the country. But this plan failed and the toad spread unchecked: Today the animals are found in parts of New South Wales in Western Australia and in the Northern Territory, where they even infest Kakadu National Park, which is considered one of the most beautiful national parks in the country .

The brownish amphibians with their protruding eyes are not very attractive from the outside. But what makes them so dangerous are glands on their heads that secrete a potent toxin that can increase heart rate and blood pressure, even in humans, and sometimes cause mild hallucinations. Birds, monitor lizards, quolls, crocodiles and snakes that eat the toads usually die in agony from the poison.

September 19, 2021, Brisbane, Queensland, Australia: Cane Toad Rhinella marina near wetland habitat in Brisbane.  Brisbane Australia - ZUMAs197 20210919_zab_s197_049 Copyright: xJoshuaxPrietox

September 19, 2021, Brisbane, Queensland, Australia: Cane Toad Rhinella marina near wetland habitat in Brisbane. Brisbane Australia – ZUMAs197 20210919_zab_s197_049 Copyright: xJoshuaxPrietox

Joshua Prieto / Imago

However, the ibis has apparently found a way to add toads to its diet without harming itself. Emily Vincent, the coordinator of a cane toad control program in eastern Australia, told Australian broadcaster ABC. Apparently, the birds pick up the toads and shake the animals until they are so stressed that they release the venom from their glands. The latter is a defense mechanism for toads when confronted by enemies, Vincent explained.

Then the birds take the toads to the stream to wash the poison off them. This is clearly a learned behavior. As Rick Shine, a biology professor at Macquarie University in Sydney, explained to broadcaster ABC, other bird species have now developed techniques to eat the toads. Some would eat the toad’s tongue, while others would just wear away bits of abdominal skin and innards, he said.

In 2019, other scientists in the Kimberley region of Western Australia made a similar observation, finding that the native water rats had learned to kill and eat cane toads without dying from their venom. The rodents slashed open the toad’s chest with their teeth, much like a surgeon would with his scalpel, and feasted on the animals’ hearts and livers. They removed the gallbladder, which contained poisonous bile salts.

Hardy amphibians

It is gratifying that a number of native animals have adapted to the toads, but that is not enough in view of their formidable reproductive ability: female toads can lay between 8,000 and 35,000 eggs at a time, twice a year. The toads grow very quickly and can be fully grown within a year.

In addition, they are extremely resilient and can even survive the loss of 50 percent of their body fluids. As omnivores, they also have a varied diet and take food away from other native animals. Other animals that eat the toad usually die from its poison. Dogs usually die within twenty minutes after eating one of the toads.

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