A、Broadcasting frightened sounds of the birds to scare them away. B、Making shooting sounds to scare the birds away. C、Hiring spe

Italy’s capital Rome is a famous tourist attraction, but there are swarms of’ birds that crowd in Rome’ s historic public squares and churches every winter, forcing tourists and passers-by to seek refuge under umbrellas. Recently, scientists have found out a good way to solve this problem. The Italian League for the Protection of Birds will broadcast bird "distress calls" over loudspeakers in the historic centers, using a technology’ it has tried in Rome’s outskirts to scare the birds away. The scientists have recorded the sound that these birds make when there is danger and they will play it over megaphones at dusk when the birds are starting to nest down. They want to chase the birds out of concentrated urban centers with distress calls and spotlights. Then the birds will head to outlying parks and suburbs. This method has been proved very efficient and there is no cruelty to birds involved since they just migrate to parks and woods outside the city. Between October and February some four million birds migrate to the Italian capital from Germany, Poland and Russia, darkening the horizon and painting abstract shapes in the sky that capture the imagination of on lookers. The huge flocks also coat cars, buildings and any one who has not found cover with bird droppings. Tourists are advised to carry umbrellas or raincoats at dusk and residents have to put up with the terrible smell for months at a time.