Sparrows are much better on just seed TM. Cake is good if you can spare some but bread, especially white bread, only fills them up but doesn't give them any nutrition. Crumbled digestive biscuits are good for both but you will probably find, if they are anything like my lot, that the starlings descend and eat really quickly but, due to their habits, lots of the food tumbles off the birdtable and onto the ground where the sparrows happily hop around and eat it up.
I feed my birds a breakfast of brown breadcrumbs, grated cheese, sultanas (soaked overnight in water), biscuit crumbs and any table scraps I have left over plus shredded suet if I have any. The robins love the cheese and the blackbirds love the sultanas but wont come to the bird table - I sprinkle theirs on the ground.
Taz x