There are 5 important elements to consider in supportive care of a sick (or injured) bird. (Note that these are supportive measures, and do not address the cause of and treatment for your bird's illness. Your veterinarian must diagnose and prescribe specific treatment for your bird.)

1. Heat: Keeping your sick bird in a slightly warmer environment than usual may help it conserve the energy it usually uses to keep its body temperature normal. However, be careful not to overheat the bird. (Panting and spreading the wings are signs of overheating.)
2. Humidity: Raising the level of humidity can be helpful for birds with respiratory disease or signs of illness. Higher humidity eases the breathing and helps the bird keep the air passages clear and moist. A vaporizer or humidifier can be used to provide extra humidity.
3. Fluids: A sick bird can become dehydrated easily, especially because it may not drink as much on its own. In many cases a veterinarian may administer fluids under the skin, and follow-up oral fluids are also very helpful. Favorite foods high in moisture content (leafy greens, fruit) will add to water intake, but check with your veterinarian first to make sure they will not worsen your bird's illness. Adding a bit of juice (of your bird's favorite fruit, like apple or grape) to the water will often encourage drinking.
4. Nutrition: Inadequate nutrition will severely impact the bird's ability to recover from the illness. The best foods to give a sick bird are high in simple carbohydrates and easy to digest. Ask your veterinarian for appropriate suggestions.
5. Quiet/Level of Activity: Keep an ill or injured bird quiet and inactive. Remove toys from the cage and limit noisy activities or move the bird to a quiet part of the house. Make sure that your bird gets adequate (10 to 12 hours) uninterrupted sleep.