If a bird is sick for a day, it is like a dog being sick for a week. That is due to the avian species' high metabolic rate — a heart rate 600 beats per minute and a temperature of 106 degrees.
Anorexia, or a loss of appetite, and lethargy, a feeling of listlessness and general inactivity, are commonly seen in sick pet birds. While not diagnostic of any specific disease, they do indicate a severely ill bird that requires immediate medical attention. Simply put, just about every serious illness will produce signs of anorexia and lethargy.
There are many causes of anorexia and lethargy in pet birds. These include cancer, viral or bacterial infections, fungal or yeast infections, parasites, endocrine or hormonal diseases and organ-specific problems, such as liver, heart or kidney failure. Some diseases such as proventricular dilation do not have a known cause but can produce the signs of anorexia and lethargy. Anorexia and lethargy are not diseases themselves but indicate a serious underlying medical problem requiring diagnostic evaluation and appropriate therapy.
Unlike dogs and cats, birds are still "wild" pets. This means that they still retain their self-preservation response. This preservation response is something unique to wild animals. In the wild, an animal cannot "act sick," every time he feels ill. If he does, he might be killed by a predator or even a member of his own group. The preservation response assures that a sick animal will not "act sick" until it is really sick and is literally dying. This is called "survival of the fittest." Birds rarely get sick overnight. Therefore, a bird with anorexia and lethargy is extremely ill and requires immediate medical attention.. Waiting and watching will only make things worse; you may actually wait and watch as your bird dies.
How do we, as veterinarians, determine what is wrong with your bird? Because many diseases can cause the symptoms of anorexia and lethargy, diagnostic tests may need to be run. These can include blood tests (a Complete Blood Count and Clinical Chemistry), gram stains and cultures, fecal tests for parasites, yeast and bacteria, radiographs (X-rays) and a psittacosis test, among others. There is no single test that will diagnose the many causes of anorexia and lethargy.
By the time many birds are seen by the veterinarian, they are literally dying. If your veterinarian recommends hospitalization, it is because your bird requires the type of critical care that cannot be given at home. Sometimes just handling a sick bird to do a physical exam or tests will stress a sick bird and it can die in the veterinarians hands.
In general, many of these birds are extremely ill. Hospitalization in an incubator with heat, oxygen and humidity is initially utilized. Fluid therapy, force-feeding, supplemental vitamins and minerals and broad-spectrum antibiotic therapy are usually indicated. If the specific cause of the illness is determined in its early stages, treatment is usually easy and inexpensive. There is no need to wait until your bird is on death's door before it sees your veterinarian. Annual check-ups, including annual wellness tests, can detect diseases early, before they cause symptoms of clinical illness, and can prolong your bird's life.
If you have an avian pet and it shows even the slightest sign of anorexia or depression, warm up its ambient environment to around 85 to 90 degrees until you can bring it into your veterinarian and do so as soon as possible.