Between 1970 and 2008 the sparrow population of England has declined by 71%. Dr. Julia Schroeder of Sheffield University has published an article in PloS ONE
of a study she undertook on the island of Lundy. her conclusions are that noise pollution is responsible for the decline. She postulates that the noise prevents the parents from hearing their brood's cries and that they therefore feed them less, resulting in weak offspring.
In Belgium the sparrow population, after a certain decline between 1970 and 1990, stabilized and local ornithologists think that the decline was due to a variety of causes, noise pollution being a possible one of them.
The steep and continued decline in England is shocking and surprising to me, since when I was in grade school, the sparrow was touted as the species that had most effectively adapted to the urban environment in England. We were taught that while the fish disappeared from the Thames and most birds disappeared from the London skies, even at the nadir of the London environment during the killer smogs of 1952-3
, the sparrow continued to thrive.