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Heavy Metal Poisoning in Birds
Gillian Willis


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"
behavior 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 toxic
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.


See Also:

Bird Safety Tips for your Home

Plants that are Poisonous to Pet Birds