As
sick as a parrot
This is one of a series of commonly asked questions in my practice – either in person, or on the telephone, or by e-mail. An apparently simple question, but as is the case with most questions in avian veterinary medicine, there is not a simple answer! There is much that has to be considered, so the pat answer or the ‘one-size fits all’ off-the-shelf remedy is not going to suit all cases!
Q. My budgerigar appears to vomit periodically, and his face is covered with sticky stuff, so his feathers are sticking together. Is this normal?
A. The phrase ‘as sick as a parrot’ is well known in football circles, but people seem surprised when I ask them in a consultation ‘is your bird being sick? Many people do not realise that birds can in fact vomit!
However, not all vomiting is serious,
or even abnormal. It may occur for what may be classed as physiological
reasons – these
are part and parcel of normal body function and activity. This is commonly
seen as the casting of a pellet in birds of prey. These birds eat animal
material containing fur, feathers, bones, and hard material like beetle wing
cases. The useful meaty parts are digested in the stomach, and then the
indigestible residue is cast back up in the form of a pellet. Raptor keepers
look out for this casting as an indicator of normal health and stomach
activity in their birds; and examination of pellets produced by wild birds
is a useful indicator of the birds’ diets.
The other common aspect of physiological vomiting is sexual: many birds naturally regurgitate food items in courtship behaviour to their mates, and obviously to their young when breeding. This may be seen as displacement activity in frustrated, sexually mature, single pet birds, when the individual will bob its head up and down and produce a sticky mess of food to its mirror, a favourite toy, or to its owner! The most frequent ‘culprits’ for this behaviour are budgerigars, but many other species of pet bird will do it, especially if they are very tame and have been hand-reared.
The procedure may be messy and unpleasant, but it is not abnormal, and does not mean that your bird is sick! It may require some management and handling advice to deal with it, but it is not a sign of an unwell bird. The bird will remain bright, lively, and eating, with good bodyweight and normal droppings.
Pathological vomiting on the other hand is induced by abnormal conditions. These may not necessarily be infectious diseases: many birds will vomit simply through over-eating or eating too quickly; some suffer from travel sickness, and will vomit during or after a car journey; others will vomit after handling, examination and injections, especially with certain drugs, or if the neck area has been touched and the crop is full. Many birds – especially seabirds – will vomit with fear or stress. Fulmars and petrels are renowned for covering handlers with evil, oily, fishy smelling vomit!
Most
birds have, as a normal part of the anatomy of the digestive system, a sac
in the neck called the ‘crop’, which is a part of the oesophagus or gullet.
Food that is swallowed is stored for a short time in this organ, and early
digestive activity may take place here, before it passes on down to the
stomach. The ingesta may be stored here while being transported to a nest,
to be later regurgitated to feed to chicks. In species like pigeons and
doves, the food is incorporated with a rich secretion from the crop lining
to make ‘crop milk’ to feed the babies.
Problems that affect the crop, oesophagus, or upper part of the stomach, may cause pathological vomiting. But once again, there is no simple disease! Vomiting may be induced by physical factors such as ‘crop burns’ in juvenile birds that are being hand-reared with a formula that is fed too hot. There may be a physical impaction with nest material such as wood shavings, or foreign bodies such as toys, ear-rings, pieces of plastic, nut shells, etc. Rarely, stones may form in the crop (ingluvioliths), akin to gallstones or bladder stones, and these will result in partial obstruction and vomiting.
Food in the crop may ferment and produce bubbles of gas or thick mucus – this usually has an underlying infectious cause, but may simply be related to the consistency or acidity of the food, or the temperature and activity of the bird. This is one form of ‘sour crop’.
Long term deficiency of vitamin A (particularly common in Amazon parrots and African Greys on a seed-based diet) will produce changes in the lining of the mouth, throat and crop that can lead to chronic infection and vomiting.
Other inflammatory diseases of the crop (ingluvitis) may be caused by infectious agents such as bacteria, viruses, fungi, or protozoa. Only bacteria respond to antibiotics such as Baytril or tetracyclines, so a precise diagnosis needs to be made before the appropriate drug can be prescribed – it is no good just dosing a vomiting bird with an antibiotic your friend has used! Included in this group would be Proventricular Dilatation Disease (PDD, or ‘Macaw Wasting Disease’), an infection resulting in damage to the nerve control of crop and stomach, and leading to flaccidity, delayed emptying of these organs, and vomiting. The usual culprits in the vomiting budgerigar which is the subject of the question are either protozoa called Trichomonas, or organisms sharing characteristics of fungi and bacteria known as Megabacteria (or Macrorhabdos). The former also produce the disease known as canker in pigeons, or frounce in birds of prey, and are treated with anti-protozoal drugs. The latter require a combination of antibiotic and antifungal, so once again a precise diagnosis is needed.
Beyond these few ideas, there are many
systemic diseases that will induce vomiting: bacterial infections including
Salmonella, E.
coli,
Campylobacter, Yersinia, Klebsiella, Clostridia and Chlamydophila; as well
as viruses such as herpes, reovirus, & PDD to name just a few! Then there
are internal fungal and protozoal diseases, particularly Aspergillosis but
also Candidiasis, Giardia and Coccidia. Intestinal worms can build up in
sufficient quantities to make a bird vomit. Liver or kidney disease may also
result in vomiting, and these may not just be infectious, but also
associated with age or diet. Poisons (toxins), especially heavy metals such
as zinc or lead, commonly cause vomiting, as will gastro-intestinal foreign
bodies or impactions by items such as ingested toys, or over-consumption of
grit.
Then we have such things as congestive heart disease, abdominal tumours, or egg-related problems, all of which increase pressure in the abdomen and thereby induce vomiting. Finally, there are some drugs used in avian veterinary medicine that are recognised to cause vomiting in birds. The antifungal itraconazole will frequently make African Grey Parrots vomit, when used at dose rates that do not affect other species. Injectable vitamins ADE in combination commonly cause birds to regurgitate within moments of the injection.
So to sum-up
- An apparently simple question does not have a simple answer!!
- There are many possible reasons for the vomiting, so as in most avian cases, proper examination and precise diagnosis are required before appropriate treatment can be given.
- Such cases cannot be solved with a quick ‘phone call!
© Alan K Jones 2007