My Garden Birds Disappear

During the late summer it seems that the majority of the birds disappear from the garden. I only see an occasional House Sparrow or Starling instead of the large numbers we had visiting earlier in the year.No Blue Tits or Great Tits visit the feeders or hang upside down on the fat balls. I do now recall however, having been reminded by writing that last sentence, that I saw two Blue Tits last