Hello,
Over the last 2-3 weeks I've noticed that there hardly seems to be any House Sparrows or Dunnocks visiting my garden and I was wondering if it's common just around this time of the year that they are 'busy' with feeding in other areas? They have been the prominent variety in my Garden up until now but in the last few weeks I've noticed a lot more Goldfinches visiting and I was also thinking that maybe that's put the Sparrows off, although I wouldn't have thought that they would have a problem with Goldfinches.
Are they not just keeping a low profile while they finish moulting post-breeding? It takes a lot of energy and can make flight harder, so reducing risk is a big deal.
It's possible your goldfinches are on migration -- sure I read somewhere that the ones that overwinter with you aren't necessarily the same ones that spend summer with you.