Many of the most common causes of illness or death in birds are due to poor husbandry practices that result in nutritional deficiencies, trauma or poisoning due to household hazards, and unsanitary housing conditions. All of these can be prevented or minimized by providing proper care. Other causes of illness include parasites and bacterial, viral, or fungal infections that can be spread by exposure to sick birds or lack of good sanitation.
It is important to recognize signs of illness promptly in sick birds so that appropriate care can be given. Signs may be subtle, so it is important to notice even slight changes in appetite, behavior, posture, etc. Due to their relatively small size and rapid metabolism, birds can become severely ill very quickly, and delays in treatment can lessen the chance of recovery.