Can birdsong cut crime?

The Mayor of Lancaster, Los Angeles County has introduced bird recordings from England, and for the past 10 months has had his city play them over 70 speakers along a half mile of Lancaster Boulevard, blended with mellow synthesizer tones, five hours a day. His claim: The bird song and music calm citizens by fine-tuning brain chemicals.  Crimes in Lancaster fell about 15% last year, compared with 2010, says the Los Angeles County Sheriff's Department, this city being part of the county, and serious crimes fell about 6%.   Critics have said that crime has been falling in other towns and cities that have not had the benefit of piped birdsong.