Cockatiels eat mostly seeds or pellets. However, it is recommended that they be allowed to consume limited quantities of other foods. Vegetables, fruits, and small amounts of meat can add variety and flavor to a cockatiel's diet. It is important that whomever is feeding the cockatiel pay attention to the ratios of different foods consumed and the age of the food given to the bird. Cockatiels will have favored and disliked foods, and will tend to eat based upon those preferences, rather than eating what is healthy for them. Food left out too long can become infected by bacteria, so it will need to be changed, if the cockatiel does not consume it within a few hours.
Some of the healthy foods that a cockatiel can eat include: well cooked chicken, fish, scrambled eggs, steamed asparagus, cooked pasta and clean water. These birds can also eat sweet potatoes, carrots, zucchini, green sweet peppers and Roman lettuce.
Cockatiels prefer eating veggies such as: sprouts, turnip greens, Swiss chard, broccoli, escarole, chicory, spinach, mustard greens, tomatoes and beet. They can as well eat fruits such as mangoes, papayas, peaches, bananas, oranges and grapes.