Not sure what you're asking - it's well known that the numbers of house sparrows have been declining recently, mainly due to the lack of suitable nest sites because of 'improvements' in building styles, and a lack of the sort of untidiness that sparrows need to live their lives.
Are you saying that you used to have house sparrows nesting around where you are and now they've gone? If so can you identify what's changed, what's different? Have you or your neighbours had some roofing work done and now they can't find their way under the tiles to nest. If so you can get some colony nest boxes to put on your house wall (out of strong sunlight).
If you're referring to the fact that there were sparrows around earlier in the year and you've not seen any lately, that's likely to be due to the fact that lots of birds head for the bushes, fields and hedgerows in late summer, feeding on the grains and seeds in arable and wild scrubby areas, only returning to gardens when wild food is scarce.