New research has found that industrial and traffic noise in urban areas could affect communication between the parent and baby birds making them less likely to be fed. Research from the University of Sheffield has found that noise in urban environments can make it difficult for the adult sparrows to hear their young impairing the chicks growth. The research compared birds living in urban areas with those living in quieter locations. It found that birds living in quiet barns and woodland areas were fed more than those in noisier environments. This led to them being heavier when they were fully fledged and better prepared for survival. In fact parent birds made 25% fewer visits in the noisy area leading to a reduction in food intake.
The sparrow is listed as a species of high conservation concern with the population in the UK declining by 66% between 1970 and 2009 with the worst declines being found in the south and east. This does seem to fit with the research. I can’t remember the last time I saw a sparrow in Sevenoaks, although I do remember they were abundant 20 years ago. I wonder how much of this is due to noise and how much is down to loss of habitat.