Common Conditions of Pet Birds

By Gregory Rich, DVM; Laurie Hess, DVM; Rick Axelson, DVM

Pet birds often become ill when they are not cared for or fed appropriately. While most avian diseases can affect any species, some species are more prone to develop certain conditions. It is impossible to list every possible disease that may afflict your bird, but the following discussion will familiarize you with some common health conditions your pet bird may encounter. If you notice the signs of these health conditions, contact your veterinarian right away.

African Gray (Grey) Parrots

  • These extremely intelligent, often high-strung birds frequently develop feather destructive behavior (FDB) because of boredom or loneliness. They will also damage their feathers because of sexual frustration from not having a mate present.
  • African gray parrots on an all-seed diet are prone to low blood calcium levels, which may lead to muscle tremors and even seizures.
  • Aspergillosis, a potentially fatal fungal infection, is commonly seen in African grays. The signs include difficulty breathing, sneezing, lethargy, weakness, and weight loss.
  • Bacterial infections of the respiratory tract may cause signs similar to aspergillosis.
  • Cancer may be seen with some frequency in this species.
  • Although uncommon nowadays, psittacine beak and feather disease virus (PBFD) may occur in young African grays and may advance to a fatal disease because of bone marrow suppression.

Amazon Parrots

  • Amazons are commonly afflicted with upper respiratory diseases, many of which result from vitamin A deficiency associated with an all-seed diet.
  • Cloacal papillomas (warts) commonly affect older Amazon parrots and may appear in their mouths.
  • Feather destructive behavior (FDB) is common in Amazon parrots, especially on their wings and legs, because of psychological stress and sexual frustration. Dark feathering may also happen due to nutritional imbalance from being fed an all-seed diet.
  • Amazons are known to exhibit mating season aggression towards their owners. Some of these birds become too aggressive to handle and are given away to shelters.
  • A syndrome of unknown cause, called Amazon foot necrosis syndrome, occurs in Amazon parrots. With this syndrome, parrots violently mutilate the skin on their legs and feet, causing excessive bleeding and tissue damage.
  • Some Amazon parrots, especially red-lored Amazon parrots, may develop epilepsy.
  • Amazon parrots on high-fat, all-seed dietscommonly develop obesity, hepatic lipidosis (fatty liver disease), atherosclerosis (cholesterol deposits in arteries), stroke, and heart disease.

Budgerigars (Parakeets – also referred to as Budgies)

  • Budgerigars (budgies) commonly develop cancerous growths (tumors) in their kidneys and reproductive organs. Kidney, ovarian, and testicular tumors may cause pressure on the sciatic nerve, often resulting in a one-sided lameness that owners mistake for an injured leg.
  • Goiter (underactive thyroid gland, or hypothyroidism) can also occur in budgies, especially when they are on a poor-quality seed diet. Most seeds contain very low levels of iodine, which the thyroid gland requires to function properly. The thyroid gland swells as it attempts to extract all the iron it can from the diet. Budgies afflicted with this condition are often overweight and have a squeaky voice. They may also regurgitate when they eat because of the enlarged thyroid gland pressing on the esophagus, making it difficult for food to pass.
  • Psittacosis (also called chlamydiosis or parrot fever) is another common condition in budgies, especially when they are in close contact with other budgies in pet stores. Budgies may carry it without showing any clinical signs, or they may show respiratory signs (sneezing, difficulty breathing, decreased ability to fly, and tail bobbing), diarrhea or a swollen abdomen from liver enlargement.
  • Obesity is common in these birds, as many owners incorrectly feed an all-seed, high-fat diet to their budgie. Hepatic lipidosis (fatty liver disease) is a problem that often results and may lead to death. This species is also predisposed to tumors called lipomas, which are related to a high-fat, all-seed diet. Xanthomas are growths that may be found on the wings and ventral abdomen. Lipomas appear as pockets of soft, white, moveable fat, while xanthomas are typically firm, fixed, and have a yellowish orange coloration.
  • Reproductive problems are very common in budgies, as well. Egg binding is seen often in pet budgerigars, even those housed alone, as single females are still capable of laying eggs. Birds often become egg bound when they are eating diets high in seed that lack calcium and vitamin D, which are critical in the formation and laying of eggs.
  • Scaley leg and beak mites (Knemidocoptes pilae) cause a crusty build up on the beak and/or feet. Beak infections result in a misshapen and elongated beak formation. (Photo at right shows a budgie with Knemidocoptes; photo courtesy of Gregory Rich, DVM)
  • Adult female budgerigars may develop a thick brown extension of the tissue on the cere (the skin around the nostrils) called brown hypertrophy of the cere. This is due to a chronic elevation of reproductive hormone levels.
  • Avian gastric yeast, caused by Macrorhabdus ornithogaster, causes weight loss and passing of undigested seed in the stool.


  • Canaries have several genetic-based conditions. The most common conditions are cataracts, male pattern baldness on the top of the head, and feather cysts, which require surgical removal.
  • An unusual form of knemidokoptic mange called tassel-foot occurs frequently in these birds, in which mites cause excessive build-up of crust on the skin over the feet, making the feet look like there are tassels hanging off them.
  • Air sac mites that infect the trachea (windpipe) and air sacs commonly contribute to respiratory disease in canaries. Affected canaries have breathing difficulty, rapid respirations, and may breathe with open mouths.
  • Owners who provide their canaries with nesting material made of fine thread often unknowingly cause a problem for their birds. The fine thread can wrap around a toe or foot, impairing the blood circulation and ultimately causing necrosis (death) of the affected toe or foot. In many cases, the toe or foot may need to be amputated.
  • Poxvirus causes crusty lesions on the un-feathered skin in canaries and may affect the respiratory system, ultimately causing death. This disease is caused by bites from pox-virus infected mosquitoes or biting flies.
  • As with other small birds, reproductive problems, such as egg binding, may be seen in canaries.


  • Cockatiels, like budgies, are commonly afflicted with psittacosis, caused by the bacteria, Chlamydia psittaci. Like budgies, cockatiels can carry this organism without any signs, shedding it in their stool and respiratory tract secretions to other birds, or they may develop respiratory signs, diarrhea, weakness, and enlarged livers.
  • Another organism that commonly affects cockatiels is the internal parasite Giardia lamblia. Birds infected with Giardia may have loose stools or show signs of being very itchy, violently attacking themselves, especially under the wings.
  • Another disease more commonly seen in cockatiels is gastrointestinal yeast infection with Candida organisms. Birds with yeast often regurgitate, lose weight, have diarrhea and a decreased appetite.
  • Birds on all-seed diets often become obese and often develop fatty liver disease (hepatic lipidosis), which can lead to death.
  • Reproductive problems are even more common in cockatiels than in budgies, even in single female cockatiels. Symptoms include egg binding, soft-shelled to shell-less eggs, and/or oviduct prolapse. Reproductive tumors are somewhat common in female cockatiels as well. (Photo of cockatiel, right, courtesy of Gregory Rich, DVM)


  • Cockatoos, like other large birds, often develop psychologically-based feather destructive behavior that is difficult to treat, particularly because they are so socially needy and require a great deal of attention from their owners. However, other problems, such as infection of skin with bacteria and yeast, may also cause feather loss. For this reason, any feather loss should be thoroughly investigated by your veterinarian.
  • Like macaws, cockatoos often regress to juvenile behavior, and it may be a very early sign of severe illness in this species.
  • Mate aggression by males upon females is a common occurrence during and immediately after breeding season.
  • Cloacal prolapse occurs frequently in cockatoos, and is seen most often in sexually mature females.
  • Lipomas (benign fatty tumors) are commonly seen in rose-breasted cockatoos who tend to become obese.
  • PBFD is a very serious disease in cockatoos. From abnormal feather formation to severe deterioration of beak tissue, PBFD will often lead to an early death.


  • A strange bleeding syndrome of unknown cause has been reported to occur in conures. When they are injured or when they have blood drawn, they bleed excessively. Luckily, this syndrome can be treated effectively if caught early.
  • Conures tend to be high-strung, and as such, feather-picking is seen with some frequency in pet conures when they are stressed or overcrowded.
  • Conures are often thought to be carriers of Polyomavirus. This virus can be deadly to a variety of larger parrots, especially Hawkhead parrots, eclectus parrots, macaws and caiques.

Eclectus Parrots

  • Eclectus parrots may develop psychologically-based feather-picking that is difficult to treat, particularly because they are so socially needy and require a great deal of attention from their owners. However, other problems, such as infection of skin with bacteria and yeast, may also cause feather loss. For this reason, any feather loss should be thoroughly investigated by your veterinarian.
  • Eclectus parrots have a higher need for vitamin A than most other parrots do, so vitamin deficiency issues such as poor feathering, swelling in the oral cavity, and beak overgrowth are common.


  • Similar to canaries, finches, especially Lady Gould finches, may be infected by air sac mites, leading to severe respiratory disease.
  • As in canaries, fine thread used as nesting material can wrap around the toes and legs of finches, impairing circulation to the limbs and ultimately requiring amputation of affected tissue.
  • When stressed by overcrowding, finches often pick feathers off each other, especially around their heads and faces.
  • These small birds often develop egg binding, especially if they are fed all-seed diets deficient in calcium and vitamin D essential for egg production and laying. Egg binding can rapidly result in death if not treated early.


  • Like other smaller bird species, lovebirds may be affected with chlamydiosis. Symptoms involve respiratory signs, weakness, liver problems, and, in advanced cases, death.
  • Various infectious causes of feather loss occur in lovebirds, including PBFD and skin infections with yeast and bacteria, particularly inside the wings.
  • Epilepsy is occasionally seen in lovebirds.
  • Reproductive problems, such as egg binding, seen frequently in other small birds, also occur with some frequency in lovebirds.

Quaker Parrots

  • Feather destructive behavior (FDB) is common in Quaker parrots, especially on their wings, chest and legs, as a result of psychological stress and sexual frustration. Dark feathering may also occur due to nutritional imbalance from being on an all-seed diet.
  • Quaker parrots on a seed-based diet are prone to obesity.


  • Macaws were the first species recognized to develop a condition that was referred to as Macaw wasting syndrome. Through decades of research, this condition was found to be an ultimately fatal disease called proventricular dilatation disease (PDD), which causes chronic and progressive weight loss, regurgitation and, in some birds, death. This syndrome is believed to be an autoimmune disease associated with a viral infection called bornavirus. No one yet understands the complete cause of the disease, as many bird species are infected with bornavirus and are not clinically affected.
  • Chlamydiosis (infection with the bacteria Chlamydia psittaci) also occurs in macaws, causing respiratory signs, diarrhea, and liver disease.
  • Oral and cloacal papillomatosis (wart-like growths) also occur more frequently in older macaws.
  • Psychologically based feather-picking often occurs in the larger species of birds that are tightly bonded to their owners. Macaws are no exception. They can become frustrated because they are bonded to, but not mating with, their human flock-mates.
  • Atherosclerosis (cholesterol plaques inside the lining of blood vessels) is common in adult macaws that have been on an all-seed diet.
  • Regression to juvenile behavior may be a sign of illness in sick macaws, especially those with gastrointestinal diseases. (Photo of hyacinth macaw, right, courtesy of Gregory Rich, DVM)

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