It's traditional for Australians to bludgeon the despised cane toad to death with a golf club or cricket bat. Now another national pastime - beer - has been enlisted in the battle to encourage more humane killings of the toxic pest. For the past two weeks people in the northern city of Darwin have been exchanging live toads for a cool glass of beer. 'We want to encourage the humane treatment of animals,' says Lindsay Wilkinson, chief executive of the local RSPCA branch organising the novel promotion. So far 154 fresh toads have been handed into its Darwin office and swapped for vouchers for a glass of ale. Although toad-catchers can claim up to six vouchers a day, the promotion has yet to spark a booze rush. 'It took a while to get going,' said one RSPCA employee. 'We had 50 through in the first week but last week 104 came in so that was a big jump. 'Some people have come in with as many as three toads, others just one. We've had a couple of people who've been in twice.' The beer vouchers are the latest tool in the battle to quell the plague-like spread of the big, ugly and poisonous toads across Australia. They were first introduced in Queensland 70 years ago in a disastrous attempt to eradicate cane beetles. Ever since they have spread at an alarming rate, decimating native wildlife, and are now estimated to number around 100 million. Even crocodiles die when they chew into the toad's toxic skin. The relentless advance has taken them to the outskirts of Darwin, where residents are making a valiant effort to defend the frontline. Local MP Dave Tollner says golf clubs and cricket bats are the most effective weapons. 'To me it seems far easier just to flog them over the head with a lump of wood.' But this horrifies animal welfare activists, who have teamed up with Coopers Brewery and a local pub for the beer promotion, which lasts until April 30. RSPCA officers kill the toads swiftly and painlessly by putting barbiturates on their skin.