House Sparrow

UK House sparrow populations have fluctuated greatly over the centuries, with a gradual decline over the last 100 years.
House sparrow numbers were not monitored adequately before the mid-1970s. Since then, numbers in rural England have nearly halved while numbers in towns and cities have declined by 60 per cent. Because of these large population declines, the house sparrow is now red-listed as a species of high conservation concern.

RSPB: Aug 2011 http://www.rspb.org.uk/wildlife/birdguide/name/h/housesparrow/population_trends_and_conservation.aspx