Bellow listed common and not so common metals and their alloys that can be found in cage materials (wires, frame), hardware (screws, padlocks, hinges), parrot toys and common stuff around your house. Some of them if ingested may have adverse affect on your parrot's health.
All birds are very sensitive to toxins because of fast metabolism, delicate skin and respiratory system, small size, and digestive system with gizzard (pH 2.0, and 42C) that allows some non-food items sit there for prolong time releasing toxins or causing obstruction, impaction, bleeding and death. Natural curiosity and cleverness that pushes parrots to reach for, to chew and taste any usual and unusual objects and strength of its' beaks put parrots even at greater risk of being exposed to toxins not only when ingested, but through skin contact or when inhaled. Toxins (like heavy metals) get usually deposited in brain, bones, feathers and some in muscle tissue; and may damage many different organs causing non-specific signs of illness.
Paint used on your bird's cage is the main concern. Powder coating is much stronger than regularly applied paint that easily flakes and can be ingested and let the cage rust.
In short – ingesting any paint or any kind of metal is never a good thing – doesn't matter how safe it is, especially there are no standards for safe levels of toxic metals established for birds.
Lead and Zinc – highly poisonous for parrots. Exposure to paint or alloys in cage wires containing metals, as Lead and Zinc is the most dangerous to parrots since they naturally not only chew on everything but also use their beaks to climb. If your cage material or hardware contains these metals it more likely will cause heavy metal poisoning in your parrot. Also your family could be exposed to lead in a dust from your parrot's activity around the cage. The most common signs of poisoning in birds besides subdued behavior and shutting down – with lead poisoning – seizures and falls from the perch, with Zinc – falls from the perch. If you have any suspicion – contact your bird avian vet immediately. The bigger the parrot the bigger the danger – the large birds can easily scratch, shave or detach by chewing up some pieces of softer metals or paint.
Beside paint Lead may be used in paint primers, in soldering metal – soldered joints in cage (distinguished from welded joints), foil on wine bottles, champagne wire, fishing weights, curtain weights, rifle bullets and pellets, stained glass, in PVC and caulk.
Industry standards for Lead refer for the safe standards established by federal government that currently allow less then 600 ppm (parts per million parts or 0.06 % by weight) of Lead in household paint.
Check with manufacturers regarding Zinc, as there are no federal regulations for its content in paint.
Zinc is essential trace element, playing important role in enzymatic activity, but if ingested in uncontrolled amounts from non-food items may lead to high accumulation and toxicity. Zinc is not only used in paint but also may be used in plating – galvanization of cage wires, hardware and some metal parts of bird's toys (galvanization is term used only for zinc coatings to protect cage metal or hardware from oxidation and make it look better). This is extremely toxic for parrots as described above.
Not to mention Zinc galvanized wire or mesh in outdoor aviaries. Don't treat outdoor aviaries with vinegar to guard your parrot against zinc poisoning – what it actually does it will etch upper very accessible oxidized zinc layer (dull whitish coat – zinc rust) and zinc coating underneath oxidized layer to some point – not necessarily remove all of it but thin it enough to make underlying metal prone to oxidation and rusting which is also not good. This procedure may be sufficient to protect small birds from zinc poisoning but it seems as the best bet to avoid zinc around parrots altogether. Other zinc and its' compounds applications: UV protection in plastics, Sun protective creams and lotions, fire retardants, wood preservatives and agricultural fungicides.
Copper is an essential trace element required for hemoglobin formation and is a component of several enzyme systems. Copper is soft metal usually used for plating (not only US Mint cent coins – copper 2.5% plated zinc 97.5%, but also hardware and decorative elements on your cage), kitchen utensils, copper wire, welding. Copper can be potentially poisonous to birds – usually oxidized copper causes troubles – storing acidic food in copper containers or slightly acidic water from copper piping may contribute to elevated levels of this metal in your bird's diet and it's easy to avoid. Copper is a popular algaecide and fungicide (used in commercial and residential pools as well as to spray vegetables and grains to prevent fungus and algae growth).
Brass is alloy of copper and zinc and usually used in padlocks – it's probably OK for small birds that are unlikely to chew the padlock, but should be avoided around parrots. You can find few documented cases of metal toxicity in parrots that chew brass padlocks.
Nickel could be potentially toxic to your bird. Even though there are little documented evidence could be found clarifying nickel toxicity for pet-birds and parrots in particular, few articles clearly show that nickel is moderately toxic to wild birds as well as poultry (especially in young actively growing birds – in experiments growth of chicks to 4 weeks of age was significantly depressed at 700 ppm nickel and above). Nickel is commonly known as human allergen (causing dermatitis upon skin contact) and its insoluble salts and soluble aerosols are highly toxic to everything live. Nickel commonly used for plating as it prevents metal corrosion (on iron and copper usually). So even if you decided that it's OK to have nickel-plated stuff around your parrot check it frequently, as it may chip and expose underlying metal to oxidation.
Tin is soft metal considered by many experts as not toxic for birds unless it's "galvanized tin" (which is misused term for galvanized sheet metal (galvanized steel) or some small galvanized iron containers) – if in doubt – consult manufacturer. According to Wikipedia metal tin itself is non-toxic but most tin salts are, as well as some organic tin compounds – TBT (tributyltin) for example. TBT is very toxic – thin layer of this polymer may serve as a protective coating on non-food glass and ceramics. Tin resists corrosion from distilled, sea and soft tap water, but can be attacked by strong acids, alkalis and acid salts. Tin is present in various alloys, such as soldering tin & bronze, pewter, bell metal, Babbitt metal and dental amalgams. Organotin compounds are used as fungicides, insecticides and bactericides and they are well known for animal and human toxicity. Additionally, these are applied as PVC and PCB heat stabilizers.
Steel /a.k.a. Wrought Iron is hard metal nontoxic (mostly because it's hard and very difficult for parrot to detach and ingest piece of it) to birds, but rust – is, so be careful as cage coating wears off and corrosion starts – consider powder coated cages versus pained. Powder coating is much stronger and structured surface of this coating provides better grip for birds.
Stainless Steel (SS)- is very hard material, that will not shave or scrape easily, will not rust under normal indoor conditions. It doesn't require any coating, plating or paint, very easy to take care for – you can power wash (just remove your beloved bird!:) and wipe the cage dry – basically nothing to worry about. Couple comments on Stainless Steel:
Some stainless steels may stain and rust if left in humid acidic environment for prolong time or if bird's droppings accumulate in some places that also keep moisture;
You can find many references saying that SS is not magnetic – this is not exactly correct. Stainless steel is any alloy that contains 10.5% or more of chromium and iron in excess of 50% and other components. Its magnetic property depends on what other components of this alloy are – nickel, magnesium, carbon, nitrogen, molybdenum…Any steel alloy with nickel is not magnetic (nickel strengthen stainless characteristic of iron and chromium alloy). Medical grade SS usually uses nickel and chromium so it's not magnetic. Alloys only with chromium (no nickel) are magnetic. Different combinations of components define magnetic power of alloy.
Some parrot's owners say that bright super glossy SS cages (shiny almost mirror-like looking surfaces) made their parrots very exited (even agitated) – it may make sense to look for SS cages that have less lustrous finish – polished surface with subdued mat tone – electro-polishing usually does just that.
Aluminum is a soft metal and by many considered as safe for birds. However few studies indicated that some birds' species in aluminum-laden habitats with high Aluminum diet have elevated aluminum level in bones and laid deformed eggs with soft shells leading to reduced hatchability. Other studies bring concerns with bone grows and body weight gain in growing chicks with elevated aluminum in the diet. So it's probably more safe not to let your parrot put his beak on aluminum stuff around your house and to avoid it in bird's toys (just as mere precaution – you never know what reaction your particular bird will have)
Most of parrot aluminum toxicity cases that were documented connected to heated aluminum foil – which is mostly attributed to fumes from its non-stick polymer additives.
Selenium, mercury, cadmium, arsenic, thallium and cobalt are potentially toxic to birds. Poisoning causes by these elements have been well documented in wild birds due to environmental exposure and infrequently diagnosed in pet birds but it seems prudent to know main sources of household exposure to these elements.
Selenium is another required dietary element that can be toxic if ingested in high amounts. Selenium used in electronic industry, glass and rubber production, photographic processing, pesticides and shampoos – avoid your parrot contact with these chemicals. Interpretation of selenium toxicity is complicated by its interaction with other metals, particularly with mercury and arsenic that may reduce selenium toxicity.
Mercury is nonessential very toxic heavy metal. It affects the immune system, alters genetic and enzyme systems, and damages the nervous system, including coordination and the senses of touch, taste, and sight. Since most of the household hazards associated with mercury were recognized and eliminated while ago – until you are feeding your parrot fish and mercury containing thermometers it's highly unlikely that your bird will have exposure to the most toxic mercury form – Methyl-mercury or elemental mercury.
Cadmium – is found in some batteries, pigments, used in electroplating, soldering, alloy manufacturing and plastic production. Cadmium and its compounds are extremely toxic even in low concentration. If ingested, bird will accumulate it in liver and kidney causing kidney damage, reduced egg production and altered behavior.
Cadmium is long known as carcinogen. Besides possible cadmium exposure through food (most of the plants have high level of absorption and accumulation of environmental cadmium – one more reason to feed your parrot organic food), burning fossil fuels such as coal and oil and smoking are other dangerous sources of cadmium exposure – since lungs absorb cadmium much more effective then guts. Do not smoke around your parrot and never let it to reach for you cigarette butts, don't burn coal or use oil lamps. Keep your artist paints (if it applies to you) out of reach of your parrot. Cadmium Yellow, Orange & Red pigments used in artistic colors, in coloring plastics and some specialty paints, in color glass and ceramic glazes (Tiffany lamps, red stoplights) also contain cadmium.
Arsenic has been used to control agricultural pests, to pressure treat wood for outdoor use (until 2003) and in chemotherapeutics. If ingested different organic and inorganic arsenic compounds accumulate in kidney and liver and may cause anemia, nervous disorders and immune system suppression. Hopefully your parrot exposure to this hazard is very limited.
Thallium sulfate (salt of heavy metal Thallium) used as rodenticide (to control rats) and household insecticide (ants and cockroaches) – is highly toxic to mammals, birds and insects used only by professional exterminators – very unlikely your parrot will be exposed to any of this unless you store and use this chemicals in your house.
Cobalt and its salts are used in nuclear medicine, enamels and semiconductors, grinding wheels, painting on glass and porcelain, hygrometers and electroplating, in vitamin B12 manufacture, as a drier for lacquers, varnishes, and paints, and as a catalyst for organic chemical reactions.
According to Wikipedia although cobalt is an essential element for life in minute amounts, at higher levels of exposure it shows mutagenic and carcinogenic effects similar to nickel. After nickel and hexavalent chromium (VI), cobalt is a major cause of contact dermatitis in people.
Play it safe – check all metals in your bird cage and on your birds toys regularly for chipping, peeling, rust & oxidation.