Posted: 09/09/2016 at 15:35
same as Dove.
You'll never achieve a balance of pests and their predators if you keep killing the predators. Insecticide kills the lot, not just 'pests'. The insect eating birds won't turn up if there are no insects (or, worse, they'll be eating poisoned insects) and everything goes out of balance.
If it's got worse with using sprays try a couple of years without sprays and see if things improve, good luck