Where have all the house sparrows gone?

During Garden Watch and since then, house sparrows have been the most common birds in my garden. In fact towards the end of the summer there were large groups (maybe up to 20) playing about.  Suddenly they’ve all disappeared! 
Still getting plenty of goldfinches, chaffinches, dunnocks, great/blue/coal tits, robins, collared doves, wood pigeon, magpies, jackdaws, blackbirds etc - but not a sparrow in sight!

Any suggestions where they’ve gone? We did have the odd one taken by a sparrowhawk, but its success rate would have been incredible to get them all. 

  • Not sure if you're still interested in this thread, but I suppose I can offer some sort of suggestion. House sparrows have an increased mortality rate now than from a few years ago due to increased air pollution, along with the typical suspects of autumn-sown cereals creating a lack of stubble fields. I think that -although flocks are certainly not as large as they once were- some birds will commute to feed on local farmland or roosting sites, and although populations are mainly sedentary, they move around the area quite a bit in search of food. Sorry if I couldn't offer any definite help.