A bird can burn itself easily if it is allowed free flight in the kitchen. Many burns occur when a bird lands on a hot stovetop, in a pan of hot oil or other food, or in a pot of boiling water. Burning can occur from direct contact with chemicals such as acids (i.e., hydrochloric acid) or bases (chlorine bleach). Also keep your birds away from electrical cords and outlets, since these, too, can cause a bird to burn its tongue if it is allowed to chew on a plugged-in cord.
If your bird has burned itself, keep it calm and warm--it could go into shock. Flush the burned area with cool water (grease burns should be sprinkled with flour before being flushed with cool water; this makes rinsing the grease away from the skin easier); apply a thin coat of baking soda paste to acid burns; base burns can be treated with vinegar. If the burn is severe or doesn't heal quickly, take your bird to your veterinarian for prompt treatment.