Lead and Zinc Toxicity in Pet Birds

Lead and Zinc are two compounds that when ingested result in what is known as heavy metal toxicity in pet birds. Many metal objects or metal-containing compounds are attractive to psittacine birds because of their natural desire to chew. Unfortunately this often results in the toxic substance being ingested and then the poisonous metal is slowly released from the digestive tract into the blood stream.

Environmental Sources

Zinc

• galvanized cages, especially when imported from out of the country

• older powder coated cages (built before 1990), a powder coating which is electrostatically applied to wrought iron or rolled steel wire

• certain bird toys

• quick link holders, washers, nuts, snap fasteners

• coins, padlocks, galvanized dishes

• twist ties, clothes pins

Lead

• antique or imported metal cages

• stained glass lead seams; decorative candle holders, window ‘suncatchers’ and lamps

• solder, chandeliers, curtain weights, fishing weights, foil from champagne bottles, costume jewelry, backs of old mirrors, bells with lead clappers, old painted surfaces (including costume jewelry), linoleum

Please note that birds that are allowed to “roam” free in their home environments are more prone to these toxicities.

Clinical Signs and Diagnosis

Zinc–Signs tend to be nonspecific and dose related and may include lethargy, lack of appetite, increased thirst and watery droppings, and vomiting. As well, chronic low-grade zinc exposure has been associated with excess feather preening and picking (especially in Cockatoos).

Lead–birds show depression, watery droppings (or bloody droppings in Amazons and Conures), and vomiting. Increased thirst and crop distension may also occur. At times birds show neurologic signs and may exhibit twitching, incoordination, circling and convulsions.

Both lead and zinc toxicosis can be diagnosed by sending off a blood profile and specific blood zinc and blood lead levels. In addition x-rays can be taken to look for heavy metal densities in the bird’s body. However, not all cases of confirmed toxicities will show up on an x-ray. Ingestion of some non-metal sources or chronic sucking on these metal objects can cause toxicity without evidence on x-ray.

Treatment

Treatment usually involves administration of heavy metal binding drugs to bind the zinc and lead and remove them from the body. This treatment is usually started by injection and then follow-up with oral medications can take place. In addition, nutritional support of the bird, maintaining hydration, and medicines to stimulate gastrointestinal movement may all be needed. Fiber supplementation (Metamucil or Citrucel powder) may be needed to promote movement of metal out of the stomach and intestines if it is seen on an x-ray.

If diagnosed early in the course of the disease the prognosis for these toxic birds can be very good. Treatment may take several weeks, but the outcome can be rewarding.