Swamphens have learnt how to make a meal of cane toads
“I HAD HEARD that some birds had begun to feed in this way but I had never witnessed it myself,” says Greg Bourke, the curator manager of the Blue Mountains Botanic Garden, Mount Tomah. He’d just witnessed a swamp hen carefully making a meal of a cane toad.
Cane toads were introduced from Hawaii to Australia in 1935 to eat scarab beetles, which had become a menace for the Australian sugar-cane industry. Populations quickly grew out of control and soon reached plague proportions.
The toads pose a risk to Australia’s native wildlife as they secrete a poison from their skin that’s toxic. Scientists have tried for some time to naturally deter animals such as quolls from consuming the toads with methods including toad sausages.
Quolls that had been exposed to cane toad in the form of a sausage are less interested in taking a bite of toxic cane toad bait, while wild quolls, unfamiliar with the toad sausage, were more likely to take a chance on the killer feast.
But when it comes to some of our birds, they seem to have learnt how to eat toads by avoiding the most toxic parts.
“At first I was not sure that the swamphen was aware of its prey but it quickly became clear that it knew exactly what to do to avoid the poison glands,” says Greg. “It positioned the toad carefully and held it tight while feeding from the underside. It was a very deliberate approach!”
“I had heard that some birds had begun to feed in this way but I had never witnessed it myself,” says Greg. “I spend a lot of time in swamps chasing my passion of carnivorous plants so frequently observe the toads and numerous wading birds, but this behaviour is a first for me.
“I’ve seen the decline of many species, particularly reptiles in the Northern Territory over the years due to cane toads, so to see this behaviour was very exciting.”
Swamphens, like crows, are clever. “These are intelligent birds and have the potential to play an important role in reducing cane toad numbers,” Greg says.
“This in turn could help support the return of other native species that have declined in numbers due to the invasive cane toad.”
These images were taken in April 2017, south of Lawn Hill National Park, Queensland.