They will eventually, but at the moment it's something new, so might take a while for them to adjust to the shape and position. Give it a few more days.
Seed, apple, cheese and potato bits are fine, although I wouldn't bother with the bread as it can cause problems with young birds as well as encouraging vermin.
Natural food is plentiful at the moment so they will be using your food ( and mine) as a welcome supplement. greedy little things!
Please don't feed wild birds on bread or other "human" food, it swells inside their crop and can kill them. As this happens some time after they've eaten the bread, they don't know to stop or not to eat it until it's too late. I've seen birds suffering like this, and it's not a pleasant death.
Plus, if there are cats around it's kinder not to encourage the birds into danger. As someone else said, there's plenty of natural food around at the moment ...