Heavy Metal Toxicity in Birds

When I refer to heavy metal toxicity I do not mean an excessive exposure to AC/DC or Metallica with the volume turned up, but rather an ingestion of lead or zinc, two toxic compounds not uncommonly ingested by pet birds. Many metal objects or metal-containing compounds are attractive to pet birds because of their shiny appearance.  As well, due to the parrots natural desire to chew, birds can pick up lead from such sources as paint and calking material in older homes, the backs of old mirrors, and stain glass molding metals.

Over the years I have seen lead toxicity from all of the above. In fact, we are currently treating an Amazon parrot that chews on the painted wood framing in an older home. Perhaps my most interesting case of lead toxicity involved an Amazon parrot that had chewed the paint off a colorful bead necklace offered by its owner as a play toy.  Unfortunately the paint on the beads was lead-based and this bird got very sick! 

When ingested the poisonous metal is digested and absorbed from the gastrointestinal tract into the blood stream where certain levels cause toxic illness. Incidentally, lead toxicity is also common in wildlife especially in bottom feeders such as ducks and geese. They ingest hunters’ lead shot that has fallen to the bottom of ponds. Raptors pick up lead from mammal prey that have been hit by lead shot.

Environmental Sources of Heavy Metals

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.

  • 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.

NecklessLead: Affected birds show depression, vomiting and watery droppings (and in Amazon parrots and conures an obvious blood-colored urine in the droppings).  Most birds have stopped eating and look fluffed and weak. At times an increased thirst resulting in crop distension may occur. Some birds show neurologic signs and may exhibit twitching, in-coordination, 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.  It is also important to realize that not all metal objects ingested by a bird contain lead or zinc.

Treatment

Treatment usually involves administration of drugs that bind to the toxic metals 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.

During this holiday season keep in mind that all pet birds that are let out of their cages need to be supervised so that they do not inadvertently ingest any harmful substances that may include some of your holiday decorations.  We want all our pets to have a safe and happy holiday season as well!  Happy Holidays to all!

Year Published: 

  • 2013

Edition: 

  • December-January

Author Name: 

Author Bio:

Dr. Peter G. Fisher is the founder of Pet Care Veterinary Hospital in Virginia Beach, VA and has a special interest in exotic medicine. www.petcarevb.com