You shouldn't feed birds any bread. I know, that is the stereotypical "bird food." But they really cannot digest it. It doesn't give them any real nutritional value. It just fills them up so that they are less motivated to eat actually healthy food, and the lack of proper nutrients can causing issues with their feathers, egg laying, and more.
If you want to feed the birds around your home or in a park, the best thing is to get some bird seed. If that is hard to come by, then peas, sunflower or pumpkin seeds, peanuts, or cracked corn (whole cooked corn kernels are also okay!) are best. You can also feed fruit, like sliced grapes.
I often thaw some frozen peas and put them out for my neighborhood birds, and they LOVE them.