 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 <unk> Show in 1954 was a parody of the futile efforts to disrupt the large common starling roosts in central London . 
