Foreign objects and bezoars in exotic birds
By the “Klinik für Heimtiere, Reptilien, Zier-und Wildvögel der Stiftung Tierärztliche Hochschule Hannover”
Dr. Marko Legler
It is not seldom that exotic birds or especially parrots take in non- digestible or indigestive food. The reasons for birds eating foreign objects is manifold and most of the time it cannot be determined exactly.
One of the important factors may though be a lack of minerals. In this respect, a lack of calcium lets the birds look specifically for a source of minerals and it often ends up by eating poisonous metals or indigestible quartz crystals.
Curtain leads, tiffany lamps, window stickers, florist’s wire or silicon sealing are still frequent sources for lead and zinc poisoning. Zinc is, however, also taken in in small quantities by nibbling at galvanised aviaries or in larger quantities by biting off zinc drops that develop during the galvanising process. But costume jewellery and rhinestones also contain heavy metals.
Another factor for wanting to eat foreign objects may be caused by a behavioural disorder due to a lack of occupation under human attention. In the wild, looking for food in particular and the thus related physical and mental stress takes up most of the day. This is often not sufficiently satisfied when being looked after by humans and it creates a replacement behaviour reflected in searching for food on the carpet or nibbling fibrous toys or seating cords as the parrots will do. Small fibrous foreign particles can in this way get into the crop and stomach or sometimes also into the intestines and form a bezoar that leads to illnesses.
Long fibres can also wind themselves around the tongue and cause injuries by cutting into the tongue. Foreign objects can also be eaten due to the birds owner’s negligence.
Wrong feeding tools such as for example when rearing large parrots or in case of forcefully feeding sick parrots, it is possible to swallow bitten off bits or feeding tubes that slipped off the feeding injections. The consequences for the animals having swallowed foreign objects are very diverse and can lead to serious poisoning (heavy metals), a digestive tract occlusion (bezoar or injuries, for example caused by wooden bits or screws. The clinical symptoms of poisoning can be a reduced general well-being, right up to serious, central nervous failure symptoms or even hemorrhaging kidneys. In case of bezoars the symptoms are mainly wretching, diarrhea or even having difficulties in defecating due to an intestinal blockage and thus causing the bird to take in excessive quantities of water. Foreign objects are detected in a veterinary practice, in most cases by means of imaging techniques. Solid metal objects can, for example be localised very well by x-rays on two levels.
A blood test will additionally detect a concentration of heavy metals in the body. Foreign objects in the crop can quite easily be palpated or made visible in an x-ray by introducing a special contrast media. While treating the patient for illnesses caused by foreign objects – apart from stabilising the patient – removing the object is the most important issue. Large object such as feeding tubes can be removed endoscopically from crop and stomach.
Bulky bezoars in the crop are removed operatively. For treating heavy metal poisoning medicaments are given that bind heavy metals in the blood and make it easier to defecate. The heavy metals must however be defecated naturally with birds. Therefore a once started treatment must be continued until the particles have completely been eliminated. Especially illnesses caused by foreign objects can be avoided by not giving the parrots the opportunity to eat them. Furthermore one should care for providing adequate food and sufficient natural occupation for the animals.
The prognosis for a treatment turns out to be more successful if it can be treated specifically and as fast as possible. As bird patients are known to hide their illnesses often for longer periods even small signs, also weight losses should be the reason for clarifying the cause.