Out in the wild, birds eat a wide variety of nuts, small pieces of meat, even another bird's eggs occasionally. A good rule of thumb is, if a food is healthy for a human, it is healthy for your bird. Birds enjoy spaghetti or a bit of chicken. Hard boiled egg is often a big hit. Almonds, walnuts or other nuts are fine in small quantities.
Many birds love cheeses and yogurt.
Monkey chow is a tasty treat and an excellent source of protein for birds. It is available at most pet stores. Cuttlebone and mineral blocks are a good source of calcium. If you have any questions about whether a food is good for your bird, call your avian vet for more information. To make sure he's getting everything he needs, supply fresh water.