Heavy Metal Poisoning in Birds
Brass is an alloy of copper and zinc. Both of these metals are potentially toxic to birds.
Brass padlocks are probably not a problem for cages of small birds who are unlikely to chew the padlock. However, they should be avoided around larger birds who are able to chew them.
There was a report recently in the Journal of Avian Medicine & Surgery of a hyacinth macaw who nearly died from zinc poisoning. He had destroyed 3 brass padlocks and had also chewed on the chrome cage wires (chrome also contains zinc).
Lead is also extremely toxic to birds. Common sources of lead include lead paint, lead fishing weights, curtain weights, lead frames of stained glass windows and tiffany lamps, foil from champagne bottles, lead solder, old pewter, lead batteries and weighted ashtrays and toys.
Copper is also potentially toxic to birds although avian toxicity from this metal is less common. Acidic foods stored in copper containers may leach out copper, and occasionally copper piping for water is a potential source of increased copper in the diet if the water is slightly acidic and has been allowed to remain in contact with the piping for some length of time. Allowing the water from the tap to run for a few minutes before filling the water dishes will prevent this problem.
Tin (not galvanized), steel and iron (not treated with antirust paints) are not toxic to birds.
Zinc is extremely toxic to birds. Sources include galvanized cage wire, clips or staples, bird toy snaps, zippers, keys, nails, plumbing nuts, nuts on animal transport cages, hardware cloth, padlocks, chrome, and some antirust paints, shampoos and skin preparations.
Birds Fall from Perches
There has been a considerable amount of discussion regarding African Greys falling from their perches. This can be "normal" behaviour in Greys - some of whom are natural klutzes, or it can be a sign of underlying disease. In Greys, low dietary calcium resulting in hypocalcemia may be a cause.
Heavy metal (eg lead or zinc) poisoning should also be considered. Lead poisoning is the most common form of poisoning in the avian species. Zinc poisoning produces similar tozic effects, except that with zinc poisoning, seizures are uncommon.
I have been consulted on two cases of birds who fell off their perches, but were also depressed and anorexic. Zinc poisoning was the cause in both of these birds.
The first case was a Blue & Gold macaw, who had been previously healthy. He presented to the vet after falling off his perch. The bird was depressed and not eating. Blood work and x-rays were negative for lead.
The bird's cage had been painted two days earlier with a rust paint. This paint contained up to 1% of zinc chromate.
The bird was treated with S.C. Lactated Ringer's Solution (LRS) to rehydrate and with antidotal chelating agents to bind the zinc. The bird responded well to treatment.
The second case occurred this past weekend. A 4-yr-old, previously healthy CAG (Congo African Grey) presented at the veterinarians with a bleeding beak sustained during a fall from her perch. The bird was depressed, was not eating and had stopped vocalizing.
On questioning the owner, the bird had been quieter than normal for a few days prior to falling off her perch on a number of occasions.
The bird had been placed in a larger, old cage two weeks previously. It had been painted with a lead-free latex paint. However, the owner stated that the cage was rusty prior to painting. I asked if she had used an "anti-rust" primer.
The owner admitted using an anti-rust primer that she had been assured was safe for birds. The bird had been chewing on the paint which had started to flake off.
X-ray was negative for lead. Blood calcium was low normal. Blood zinc levels are pending.
The bird was given calcium gluconate, LRS, started on chelation therapy and placed in an Aquabrood unit. Yesterday (one day later), the bird was much brighter, more active and eating fairly well. Zinc poisoning from the "anti-rust" paint is suspected as the cause of this bird's illness.
When considering paints for your bird's cage, ensure that it is both free of lead AND of zinc.
Paints to prevent or to cover rust, usually contain zinc salts and should not be used around birds.
Heavy metal poisoning should be considered as a reason for unexplained falls from the perch.
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