Why Caffeine is Toxic to Birds

Chocolate contains a substance called theobromine. Caffeine & theobromine belong to a chemical class of alkaloids called methylated xanthines. These are found in coals, coffee, tea & in chocolate. As a class of drugs, Methylated xanthines cause central nervous system (CNS) stimulation, diuresis (flushing of fluids through the body), cardiac (heart) muscle stimulation, & smooth muscle stimulation.

Methylxanthines are absorbed very quickly & easily from the oral cavity & intestinal tract. The liver is needed to metabolize these chemicals, & the waste products are excreted in the urine. These chemicals primarily affect the CNS & kidneys. These chemicals cause increased motor activity & also result in tachycardia (too fast a heart beat.) Because of the increased motor activity, seizures may occur. The kidneys may be affected causing diuresis & very high urine output. This may lead to dehydration. Respirations may become too rapid, & hyperthermia (too high a body temperature) may occur, resulting in death. There is NO antidote for these drugs. We may only treat symptoms with supportive care & drugs to decrease their severity.

Toxic dosages for birds are not well established. In dogs the toxic dose is approximately 200 mg/kg of body weight. In cats the lethal dosage is only 80 to 150 mg/kg of body weight. (higer metabolism means that less is needed to cause toxic effects.) A cup of coffee may contain 35 to 85 mg. A 12 ounce bottle of cola contains approx 50 mg. Now these levels would mean that a 1 kg (2.2kg) cat would need to drink1 1/2 to 3 colas for death to occur. However, since a bird has a much higher metablolism than a cat, & a much smaller body size than a cat, we can safely say that it would take a much smaller dose for toxic effects & possibly death to occur.

Since we are unsure of the toxic dosages in birds, one definitely should avoid ALL caffeine & chocolate consumption for pet birds. (theobromeine & caffeine are both found in chocolate-- this means that chocolate packs a double whammy!) I reccommend that these substances be avoided in ALL pet species.

I feel that my birds have enough energy as it is. Why rev their systems up even more???

Sources:
1. Veterinary school lecture notes
2. Clinical & Diagnostic Veterinary Toxicology. Gary Osweiler, et Al.

Onions contain the chemical, n-propyl disulfide. Ingestion of LARGE amounts of raw or cooked onions in some animal species can cause toxicity from this chemical which denatures hemoglobin leading to destruction of red blood cells. This causes anemia, weakness, jaundice, bloody urine and eventually death 1- 6 days after the ingestion. Cattle appear to be more susceptible than other species, but dogs, horses and rabbits are also susceptible. I am not aware of reports of toxicity in the avian species.

Feeding a bird SMALL amounts of onion either raw or cooked is unlikely to cause toxicity. Best to avoid feeding to dogs or to rabbits either raw or cooked.

Gillian Willis
Vancouver, B.C.

Certain UNCOOKED dried beans contain what are referred to as "proteolytic enzyme inhibitors." These enzyme inhibitors may prevent or decrease the utilization in the body of substances such as trypsin and chymotrypsin to produce nutritional deficiences.

Beans that can interefere with proteolytic enzymes are lima, kidney and soybeans. Cooking of the beans destroys these enzyme inhibitors. Other dried beans do not appear to contain these enzyme inhibitors, or if present, are in low concentrations.

The fava bean (Vicia faba) can cause a condition known as "favism" in susceptible individuals. In humans, this can occur from ingeston of the beans or inhalation of the pollen. Clinical manifestations include gastrointestinal upset, hemolytic anemia, bloody urine, jaundice and shock. This appears to be a hypersensitivity reaction.

Gillian Willis
Vancouver, B.C.

ASK THE VET (Zinc Toxicity)

This article first appeared in SQUAWK, the newsletter of the Big Apple Bird Association, and appears here with permission.

In my last column, I wrote about lead poisoning. In this column I would like to talk about a second type of heavy metal toxicity -- zinc. Birds can be exposed to zinc if they are housed in flights or cages made of galvanized wire, since zinc, and sometimes lead, is often a component of this wire and the clips used to construct these flights. Zinc is also a component of galvanized food dishes, certain game pieces, and pennies minted after 1982. In addition, the white rust that can form over zinc is also toxic to birds.

The signs of zinc toxicity may be variable. Birds exposed to a large amount of zinc may display ataxia (loss of balance), green diarrhea, and may die suddenly. Chronic exposure may be expressed as depression, intermittent lethargy, neurologic signs such as seizures and ataxia, and increased thirst and urination. Death may occur as a result of anemia and damage to internal organs.

Just like the diagnosis of lead toxicity, diagnosis of zinc toxicity can be very difficult. Radiographs may demonstrate metallic densities in the gastrointestinal tract. Blood levels for zinc may be run in a laboratory.

Radiographic and clinical signs are the same for zinc and lead toxicities; thus one can't be differentiated from the other. Fortunately, treatment is the same for both.

1. Cathartics may aid in the passage of small particles.
2. A magnetized instrument may be employed to remove galvanized wire pieces from the digestive tract.
3. Chelating agents may also be used, either given orally or by injection.
4. Surgery or endoscopic removal may be necessary to remove zinc particles that are visible radiographically.

As with lead, the best way to avoid zinc toxicity is by preventing your bird's exposure to it.

Holiday Hazards

INTRODUCTION:

During the festive season when there are so many more interesting things to tempt the curiosity of our feathered friends we need to be aware of items that are of potential danger.

PLANTS:

Christmas trees are usually firs and pines. There have been no reports of toxicity from ingestion of firs. Pines are not usually considered toxic to the avian species, however there is a risk of physical trauma from the sharp pine needles.

Mistletoe berries are toxic and should be kept out of reach of birds. Holly berries can cause gastrointestinal (GI) irritation. Poinsettia, although not considered a highly toxic plant, can exude a milky sap which can cause GI irritation as well as marked eye irritation.

DECORATIONS:

Angel hair and tinsel are made of plastic. The metallic colouring of tinsel is nontoxic, but there is concern for possible airway or GI tract obstruction if ingested. Snow spray particles are also plastic and nontoxic. The propellant of the aerosol sprays may be freon so these products should not be sprayed around birds. Christmas tree bubbling light fluid contains methylene chloride which is a very toxic solvent and which can cause marked irritation to eyes and mucous membranes. Christmas tree flocking is usually made from wax or plastic and not expected to cause toxicity. Fireplace colours and yule logs contain salts of heavy metals such as lead, copper, arsenic, barium and selenium. Chewing on these logs could cause heavy metal poisoning.

FOOD:

Avoid allowing your birds to share your alcoholic beverages, coffee (decaffeinated coffee is safe), chocolate and salted foods (nuts, potato chips etc.). Have some unsalted nuts available as treats for your birds. Give only human grade roasted, unsalted peanuts (risk of aflatoxin poisoning from raw peanuts).

FUMES:

Birds very susceptible to the toxic effects of fumes. Teflon-coated cookware should NEVER be used in homes where there are birds. The fumes generated by self-cleaning ovens have caused death in birds. Cigarette smoke can cause respiratory tract irritation and allergic skin disorders in birds as well as potential nicotine poisoning. Cigarette butts are highly toxic if ingested. Marihuana smoke can cause marked sedation in birds. Avoid room odorizers and air fresheners. Boil up herbs such as cloves and cinnamon instead of using commercial products.

OTHER:

Coloured metallic gift wrap may contain toxic substances, the main danger, however, is possible GI tract obstruction. Provide your birds with their own gift packages wrapped in plain paper to open. Silica gel packages are found in boxes containing new shoes, electronic and camera equipment. The crystals of silica gel are nontoxic but GI tract obstruction is a remote possibility if the package was ingested by a large bird.

FIRST AID:
Inhalation:

Take bird into bathroom and run shower (steam often helps to minimize upper airway irritation and to help breathing). Eye exposures: Flush with water or artificial tears.

Ingestion:

Give an antacid preparation (eg Milk of Magnesia) or activated charcoal suspension (if part of your first aid kit).

After first aid measures have been carried out, place bird in a hospital cage, keep warm and contact your avian veterinarian or Animal Poison Control Centre immediately for further advice.

Prepared by:

Gillian Willis
Vancouver, B.C.
December, 1996.

WEBSITE DISCLAIMER: All the above information is given solely for benefit of general understanding of the importance of bird health. This in no way implies medical advice. If in a medical emergency situation, SEEK THE ADVICE & TREATMENT OF AN AVIAN VETERINARIAN or ANIMAL POISON CONTROL CENTER.

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