Another Cock Spara?

We have an unknown shrub in the garden which this year,has become a haven for House Sparrows.
It is not Evergreen so there is no cover to be had from the bad weather.But there is a community of some 2030 birds in there. Occasionally they fly out in groups of 10 or so,and then the next group go out.They must have a food source,but I might say,it is not from my feeders???
May be they will realise before long that just over the fence is a wonderful variety of snacks! lol