Depending on how young they are they can't eat on their own, their mother normally puts it down their throat, so if you have rescued them and their mother is no where to be seen, the best option is to take them to a bird sanctuary so they can feed them and learn to fly. But just for the record baby birds eat soggy bread or a mixture of mushed up dog food, cat food, bread and water is quite nice for them. (but don't put too much water in as it will go to runny)
