from a wide area and breeding populations may not be greatly affected. In Europe, the varying legislation and mobile populations mean that control attempts may have limited long-term results. Non-lethal techniques such as scaring with visual or auditory devices have only a temporary effect in any case. Huge urban roosts in cities can create problems due to the noise and mess made and the smell of the droppings. In 1949, so many birds landed on the clock hands of London's Big Ben that it stopped, leading to unsuccessful attempts to disrupt the roosts with netting, repellent chemical on the ledges and broadcasts of common starling alarm calls. An entire episode of The Goon Show in 1954 was a parody of the futile efforts to disrupt the large common starling roosts in central London. Where it is introduced, the common starling is unprotected by legislation, and extensive control plans may be initiated. Common starlings can be prevented from using nest boxes by ensuring that the access holes are smaller than the diameter they need, and the removal of perches discourages them from visiting bird feeders. Western Australia banned the import of common starlings in 1895. New flocks arriving from the east are routinely shot, while the less cautious juveniles are trapped and netted. New methods are being developed, such as tagging one bird and tracking it back to establish where other members of the flock roost. Another technique is to analyse the DNA of Australian common starling populations to track where the migration from eastern to western Australia is occurring so that better preventive strategies can be used. By 2009, only 300 common starlings were left in Western Australia, and the state committed a further A$400,000 in that year to continue the eradication programme. In the United States, common starlings are exempt from the Migratory Bird Treaty Act, which prohibits the taking or killing of migratory birds. No permit is required to remove nests and eggs or kill juveniles or adults. Research was undertaken in 1966 to identify a suitable avicide that would both kill common starlings and would readily be eaten by them. It also needed to be of low toxicity to mammals and not likely to cause the death of pets that ate dead birds. The chemical that best fitted these criteria was DRC-1339, now marketed as Starlicide. In 2008, the United States government poisoned, shot or trapped 1.7million