Please note:This document is a review of the academic literature relating to copper toxicosis in wild birds. The review was conducted out of frustration with uninformed opinionsconcerning the potential dangers of copper birdbathstowild birds. It should be noted that I am not a scientist, and I would be happy to discuss this document or be presented with any further evidence.
Etienne Deleflie
There is no clear evidence, in the scientific literature, that water drunk from a copper vessel poses any kind of health threat to wild birds. Nor are there any credible reports of the same. That said, copper toxicosis is known to occur in wild birds. It is typicallya result of birds frequenting sites that are contaminated by industrial activity and mining. The question of thetoxicity of copper to wildlife is one that concerns the quantities that the animal is exposed to. In this document, research concerning heavy metal poisoning in birdlife is reviewed, and a projection of the likely hood of copper toxicosis in birds, resulting from drinking water in a copper vessel, is made. The general conclusion is that it seems incrediblyunlikely that there might be enough copper leaching into the water contained in a copper birdbath to harm birds.
Copper is essential for the normal growth and metabolism of all living organisms including birds (Eisler, 1998). Different animals react differently to exposure to copper. Sheepand cattle are oftenaffected by copper toxicosis. Birds (and mammals) are considered relatively resistant to copper (Eisler, 1998). There are quite a few reports of copper toxicosis in the commercial avian industry(poultry farming, etc.) and some in wild birds. These are all discussed below.
One source for the fear that copper might contaminate drinking water for birds comes from reports of heavy metal toxicosis resulting from putting USAcopper pennies into pet birds' drinking water. This is usuallydone to reducealgae growth in the water. Copper pennies are a known source of zinc toxicosis in birds(Richardson, 2006;Droual, Meteyer, and Galey, 1991), not copper toxicosis. As reported by Richardson (2006): "Pennies minted since 1983 contain 99.2% zinc and 0.8% copper and one penny contains approximately 2440 mg of elemental zinc." Zinc and lead toxicosis are much reported in pet birds (Richardson, 2006;Lightfootand Yeager, 2008;LaBonde, 1995).LaBonde (1995) says that heavy-metal toxicities other than lead and zinc rarely occur in pet birds. Copper toxicosis in pet birds is usually the result of the ingestion of copper pieces.
It is more difficult to findapplicable research where wild birds are concerned. Eisler (1998) offers a good starting point with a review of reports of copper hazards to fish wildlife and invertebrates.Eisler's text can be accessed here.Henotes a report from 1954 where copper sulfate was used to control various species of toxic algae:
"Prior to treatment, blooms of Anabaena flos-aquae, Aphanizomenon flos-aquae, and Microcystis aeruginosa were associated with deaths of migratory waterfowl, game birds, songbirds, game, and domestic animals (Rose 1954). Most of these species of algae were controlled within 24 h by 1.0 mg Cu/L as copper sulfate. Copper treatment had no adverse effects on bottom fauna but populations of crustaceans (daphnids, copepods, entomostracans) were reduced. One year after treatment no deaths of birds or mammals were recorded (Rose 1954). "
This report highlightscopper's known benefit to birds when added to water; it reduces algae, but does little to establish what might be considered a non-toxic dose of copper.
Eisler (1998)reports on the effects of controlled doses of copper fed to mallards, ducks and domestic chickens. Studies cited experimented with scales of dosage levels;
"... Day-old chicks fed diets containing 10 (control), 100, 200, or 350 mg/kg ration for 25 days: Reduced weight gain in the 350 mg/kg group; other groups same as controls "
Day-old chicks only began to show signs of adverse affects when the copper component of their diet reached 350mg/kg. Other studies show high gizzard erosion with copper densities of 500 and 1,000 mg/kg (fed for 4 weeks). Young Turkeys only showed negative signs when fed 800mg/kg:
"Week-old poults fed corn-soybean meal supplemented with 100 to 800 mg/kg ration: No adverse effects on survival; growth reduced only at 800 mg/kg diet" Eisler (1998)
Mallards showed a preference for water with a certain amount of copper.
"Mallards seem to prefer drinking water containing 100 mg Cu/L over distilled water (Table 6); however, these birds were molting and this may have influenced their response because trace mineral requirements rise during molting (Rowe and Prince 1983)." Eisler (1998)
Comparatively, humans are far lesstolerant to copper than birds. Copper toxicosis is observed in human infants after drinking water with a copper concentration of 3 mg/L for 9 months (Eisler 1998). In Australiathe safe drinking water concentrationof copper is 2mg/L.Eisler (1998) notes that the conduction of water in copper pipes can be responsible for introducingup to 1mg of copper per litreofwater.
The above figures are sufficient to make a crude projection. If the water used to fill a copperbirdbath came from copper pipes then its copper content may already be up to 1mg/L. Assuming that a copper birdbath will leach around as much copper into the water as water pipesdo, then it will contribute another 1mg/L, for a total of 2mg/L. This concentrationof copper is 50 times less than the safe levels consumed by mallards as mentioned above.
Lead toxicosis is much reported in wild birds (Lucia, André, Gontier, Diot, Veiga, and Davail, 2010;Lewis, Poppenga, Davidson, Fischer, and Morgan, 2001).
There are few reports of copper toxicosis in wild birds. One study(Henderson, Winterfield, 1975) reports lesions in Canada geese after having ingested copper sulfate at about 600 mg/L of water from a small man-made pond. In acidic environments where, for example, acid rainis known to occur, copper birdbaths are likely to produce copper sulfates. However, given that thecopper content of the water will be around 2mg/L, concentrations of copper sulphates will be one or two orders of magnitude lower than the reportedly toxic 600mg/L.
In a paper published in 2008, Thomas, and McGill make an analysis of the potential toxicology of birds ingesting sintered tungsten–bronze (containing 44.4% copper).Sintered tungsten–bronze is a suggested substitute for lead used in discharged lead shots and fishing weights, which are known to cause lead poisoning in wild birds.Thomas, and McGillsimulated the ingestion of eightsintered tungsten–bronze spheres in ducks to observe the effective rate of release of copper into the ducks' digestive system. Theyconclude:
"The release of 43.17 mg copper/day from eight tungsten–bronze spheres, while exceeding the daily copper requirements of domesticated birds, is far below the levels of copper known to cause copper toxicosis in birds." (Thomas, and McGill2008)
For a bird to ingest the equivalent of 43.17 mg of copper/day by drinking water from a copper vessel, it would have to drink in excess of 20L of water in a day. Lets assume that the above estimation that a copper birdbath will leach 1mg of copper for each litre of water iswrong by an order of magnitude: if a copper birdbath was to leach 10mg of copper for each litre of water, a wild bird would still need to consume 2L of water per day to approach the copper concentration thatThomas, and McGill say is still safe.
Notwithstanding the differences in bird species, in their specific diets, in the proportions of water ingested from a birdbath and ingested through vegetable matter or other water sources, in the different types of copper compounds that may be present in the water consumed; it still seems incredibly unlikelythat water ingested from a copper vessel will pose a credible health risk to wild birds.
References
Eisler, R., 1998.Copper hazards to fish, wildlife, and invertebrates: A synoptic review(No. USGS/BRD/BSR--1997-0002). GEOLOGICAL SURVEY WASHINGTON DC. (http://www.pebblescience.org/OLD-SITE/pdfs/CHR_33_Copper.pdf)
Thomas, V.G. and McGill, I.R., 2008. Dissolution of copper, tin, and iron from sintered tungsten–bronze spheres in a simulated avian gizzard, and an assessment of their potential toxicity to birds. Science of the total environment, 394(2), pp.283-289.
Lightfoot, T.L. and Yeager, J.M., 2008. Pet bird toxicity and related environmental concerns.Veterinary Clinics of North America: Exotic Animal Practice,11(2), pp.229-259.
Richardson, J.A., 2006. Implications of toxic substances in clinical disorders.Clinical avian medicine. Spix Publishing Inc., Florida, pp.711-719.
LaBonde, J., 1995, January. Toxicity in pet avian patients. InSeminars in Avian and Exotic Pet Medicine(Vol. 4, No. 1, pp. 23-31). WB Saunders.
Lucia, M., André, J.M., Gontier, K., Diot, N., Veiga, J. and Davail, S., 2010. Trace element concentrations (mercury, cadmium, copper, zinc, lead, aluminium, nickel, arsenic, and selenium) in some aquatic birds of the Southwest Atlantic Coast of France.Archives of environmental contamination and toxicology,58(3), pp.844-853.
Lewis, L.A., Poppenga, R.J., Davidson, W.R., Fischer, J.R. and Morgan, K.A., 2001. Lead toxicosis and trace element levels in wild birds and mammals at a firearms training facility.Archives of Environmental Contamination and Toxicology,41(2), pp.208-214.
Henderson, B.M. and Winterfield, R.W., 1975. Acute copper toxicosis in the Canada goose.Avian Diseases, pp.385-387.
Droual, R., Meteyer, C.U. and Galey, F.D., 1991. Zinc toxicosis due to ingestion of a penny in a gray-headed chachalaca (Ortalis cinereiceps).Avian Diseases, pp.1007-1011.
FAQs
Is copper safe for birds? Drinking water from a copper vessel is perfectly safe for birds. The levels of copper required to cause toxic effects in birds is far far higher than the amount of copper that will leach into the water from a copper bird bath.
How many pennies should I put in bird bath? ›
To keep algae growth from your bird bath drop some pre-1982 copper pennies in. I have what I would call a normal size bird bath & I use 7 pennies. The reason for the pennies being pre-1982 is that before that year, the pennies contained copper, a natural algicide.
What level of copper is toxic? ›
Copper toxicity means you have more than 140 mcg/dL of copper in your blood.
What is the safest bird bath? ›
The best bird bath for birds will be one that has a thick rim for perching on and a nice rough bottom so their feet won't slip. In nature, most birds use water sources at ground level. Some bird baths are made to put directly on the ground, but there's always danger from predators to consider.
What is the easiest bird bath to keep clean? ›
To make life easier, you could opt for a concrete bird bath or a basic plastic basin bird bath. Copper bird baths stay naturally cleaner for longer because copper is an algaecide, meaning it does not allow algae to grow.
How much hydrogen peroxide do you put in a bird bath? ›
Hydrogen Peroxide: Mix one part hydrogen peroxide to one part water. Just like the vinegar method, soak the basin with hydrogen peroxide mixture, scrub thoroughly, and rinse thoroughly afterward.
Is it OK to put bleach in bird bath? ›
Using Bleach to Clean a Bird Bath
Some people do use bleach to clean their bird baths since it can eat away at debris and stains. If you feel this is the method you want to use, make sure to thoroughly rinse all residue from the bird bath until most of the smell is gone before refilling for the birds' enjoyment.
Can you put apple cider vinegar in a bird bath? ›
Adding 1 tsp of apple cider vinegar per gallon of water will help prevent algae from growing in your bird bath. It makes the water slightly acidic which kills the algae. It's important to dilute the apple cider vinegar so that it isn't too strong.
Do copper bird baths get too hot? ›
Metal bird baths can be attractive and durable, but they can also become excruciatingly hot in the summer sun. In extreme cases, hot metal can cause burns.
Do you use bleach or vinegar for bird bath? ›
Instead of using soap or bleach to clean the bird bath, the National Audubon Society recommends scrubbing it with nine parts water to one part vinegar. You might want to let the solution soak for a few minutes. Be sure to stay close to the bird bath so no birds sneak in!
Hydrogen peroxide is considered to be generally safe for birds. When dissolved in bath water, hydrogen peroxide has no effect, even when a bird encounters it. Therefore, hydrogen peroxide applied on the cage or within the cage is a safe cleaning option.
How do you test for copper toxicity? ›
Copper toxicity is diagnosed through testing.
...
Tests for copper toxicity include:
- Total copper blood test, also known as a total copper serum test.
- Urine test.
- A liver biopsy to measure copper levels.
- Blood ceruloplasmin test.
- Vitamin B12 level test.
Copper toxicity can also trigger the following neurological and psychological symptoms: sudden changes in mood. symptoms of depression or anxiety. feeling irritable or overexcited.
Is coffee high in copper? ›
Coffee can contain anywhere from 1.2-2.1 mg of copper per cup. On average, coffee has about 0.5 mg of copper in one serving (8-12 oz). This is very low, which means that you would need to consume a lot of coffee to get a significant amount of copper out of your diet.
What is the best way to sanitize a bird bath? ›
To keep your birdbath fresh, just rinse and scrub it with nine parts water, one part vinegar. Skip the synthetic soaps and cleansers; they can strip the essential oils off of bird feathers. And make sure to refill the water every other day to keep it from bugging up.
Should I put rocks in my birdbath? ›
Give Your Birds Perching Spots
If you happen to have a deeper bird bath, you can make it more appealing by adding in a few rocks in the middle or along the edges. This will give birds a place to land so they can splash and preen themselves in the water.
Where is the safest place for a bird bath? ›
The best place for your bird bath is somewhere where birds can see it, in dappled shade, somewhere that's not too exposed, and near enough a tree or shrub with branches that birds can escape to if they think they may be in danger.
Can I use Dawn to clean bird bath? ›
Because birds clean themselves and defecate in baths, the water needs to be refreshed and cleaned often. We recommend scrubbing the bowl with hot water and dish detergent such as Dawn. If algae is present, it's best clean the bowl with a mixture of one part bleach to 10 parts water.
What is the best natural bird bath cleaner? ›
Rowden recommends using a solution of nine parts water to one part vinegar for cleaning a bird bath. Avoid the use of harsh chemical or abrasive cleaners, which can damage the bird bath and the surround area and be unsafe for birds and other wildlife who might stop by for a dip or a drink.
Can you use Clorox to clean a bird bath? ›
Scrub thoroughly
Stubborn stains in a bird bath are usually caused by chemicals in rain, tap water or well water as well as organic debris. Fill the basin with a quart of water, add 1/2 cup of household bleach, then scrub the basin with a wire brush until any gunk or discoloration disappears.
One of the best ways to use baking soda in the garden is to clean your bird bath. “Shake baking soda into the basin. It removes mold easily and is safe for birds,” says Birds & Blooms reader Stephen Holland. “Cleaning the bird bath isn't my favorite task, but it's more fun when you use baking soda and white vinegar.
How often do you clean a bird bath with vinegar? ›
A clean, filled birdbath can be an oasis for many species of birds. For the best results when cleaning the birdbath… Thoroughly clean the birdbath 2-3 times per week depending on how many birds are using it. Use a jet or pressure hose setting to rinse out the birdbath between regular cleanings.
How do you make a bird bath safe for birds? ›
Making a bird bath
- It needs to have shallow sloping sides with a shallow approach to water.
- To allow different species to bathe, provide a sloping bath, so the water is between 2.5cm and 10cm (1-4 inches) deep.
- Make sure the surface of the bath is rough so birds can grip it with their claws, and not slip.
If you have an algae problem, your best friend is white vinegar. White vinegar can quickly kill algae but is not harmful to birds, insects and the majority of plants.
Can you put tap water in a bird bath? ›
The short answer is yes - generally speaking, if your tap water can be consumed by humans, it can be used in a bird bath. However, if you're still not sure, bottled spring water or filtered tap water will work too. Birds are attracted to the sound of running water.
Can you put peroxide in a bird bath? ›
You can use hydrogen peroxide, baking soda, or distilled vinegar to clean out your concrete bird baths. No matter which substance you use, always start by dumping out the old water and gathering some basic supplies like gloves, a bucket or bowl, a designated scrub brush, and your cleaning product.
Can you use lemon juice to clean bird bath? ›
Keep your bird bath clean.
Don't wait until the water gets icky! If you see the water is discolored or there is algae, scrub with baking soda, lemon juice or white vinegar and then rinse well.
Can you put salt in a bird bath? ›
For the safety of birds and other animals, salt should never be added to birdbaths.
Is it better to put a birdbath in the sun or shade? ›
Place your birdbath in the shade if possible, to keep the water cooler and fresher. Having trees nearby will also provide branches on which they can preen. Arrange stones (or branches) in the water so birds can stand on them to drink without getting wet (this is particularly important during freezing weather).
Is copper in bath water bad? ›
Copper will not enter your body through skin or by breathing in vapours while showering or bathing. Bathing and showering in water that contains copper should not be a health risk.
Do Copper Pennies in the Bird Bath Help? You may have heard that putting a few copper pennies will help with keeping bird bath water clean, but is this true? Yes, up to a point. Copper does slow the growth of algae and some bacteria somewhat.
What does baking soda do to birds? ›
Baking Soda
If pigeons and other nuisance birds are invading your patio space or window sills, try sprinkling baking soda anywhere they like to perch. Birds don't like the feel of the baking soda under their toes and will avoid it at all costs.
Is vinegar good for birds? ›
Yes! Apple cider vinegar has many outstanding qualities that are beneficial to pets in general and birds are no exception. In my book, “A Guide to a Naturally Healthy Bird”, I write about the benefits of using ACV as a supplement in your bird's diet.
What does vinegar do to birds? ›
A few drops of white vinegar or apple cider vinegar added to your bird's water bowl can help control the growth of harmful yeast and bacteria in the bird's body. However, you should always check with your avian vet before adding it to your pet's diet.
How do you test copper with vinegar? ›
Pouring vinegar over the pennies helps break up this copper oxide and expose the pure copper on the penny. As the penny dries and is exposed to the air, a chemical reaction occurs and the penny turns green!
What are symptoms of high copper levels? ›
Copper buildup in the central nervous system can cause symptoms such as:
- Changes in behavior.
- Stiff muscles.
- Tremors, shakes, or movements you can't control.
- Slow or repeated movements.
- Weak muscles.
- Trouble swallowing.
- Slurred speech.
- Poor coordination.
Dermal absorption of copper has been demonstrated through intact and burned human skin.
Which organ is mostly affected by copper toxicity? ›
However, serious health problems from long-term exposure to copper can occur. Severe poisoning can cause liver failure and death.
What organ is at risk for copper toxicity? ›
Acute liver failure can occur due to direct copper toxicity-induced tissue necrosis.
What organ does copper affect? ›
The build-up of copper in the body damages certain organs including the liver, nervous system, brain, kidneys and eyes. In around half of cases, only the liver is affected. The copper begins to accumulate at birth, but symptoms appear most commonly during the teenage years.
The richest dietary copper sources include shellfish, seeds and nuts, organ meats, wheat-bran cereals, whole-grain products, and chocolate [1,2].
What top food is high in copper? ›
Food Sources
Copper is found in highest amounts in protein foods like organ meats, shellfish, fish, nuts, and seeds as well as whole grains and chocolate.
Are blueberries high in copper? ›
Blueberries are a good source of manganese and vitamins C and K1. They also provide small amounts of copper, as well as vitamins E and B6.
Are birds allergic to copper? ›
The U.S. EPA considers copper to be practically nontoxic to bees and moderately toxic to birds. Studies with several aquatic species have found copper to be highly to very highly toxic to fish and aquatic life.
Do birds like copper bird feeders? ›
Copper Lantern Bird Feeder is a classy carriage lantern bird feeder. Perching birds like Cardinals will love this metal feeder with extended perches.
What metal is bird safe? ›
In fact, stainless steel is the preferred metal to use with parrots. It is a hard surface that can stand up to a large beak and is easily cleaned. Metals that are nickel plated are also safe for use with parrots. Steel and iron are safe metals, but they will rust when introduced to water.
What kind of bird baths do birds like best? ›
Water Movement: Moving water will attract more birds than stagnant water in a simple basin. A birdbath that includes a dripper, mister, water spray, bubbler, or fountain is a better choice to attract a wide range of bird species.
Which animal is most susceptible to copper toxicity? ›
Acute and chronic copper poisoning (toxicosis) can affect animals in most parts of the world. Sheep are most frequently affected, although other species are also susceptible.
What are the symptoms of too much copper in the body? ›
Symptoms of long-term exposure include:
- Anemia (low red blood cell count)
- Burning sensation.
- Chills.
- Convulsions.
- Dementia.
- Diarrhea (often bloody and may be blue in color)
- Difficulty speaking.
- Fever.
Copper & Glass Hummingbird Feeder
This stunning hummingbird feeder will stand out in your backyard for all the right reasons. Hummingbirds will easily find this copper feeder that actually holds 32 oz. of nectar.
Suet is great, but only in the winter months since it goes rancid quickly in the heat. Safflower seeds, nyjer seeds and peanuts are other good choices that will attract a variety of species. Foods that have no nutritional value for birds or should not be fed to them include bread and chocolate.
Should we not put out bird feeders? ›
It's not necessary. Bird feeding is most helpful when birds need the most energy, such as during temperature extremes, migration and in late winter or early spring, when natural seed sources are depleted. Most birds don't need your help in the summer.
Can birds recover from metal poisoning? ›
In cases of lead toxicosis, symptoms may only appear in a very sick bird who is near death. If, however, the poisoning is diagnosed and treated early, your bird may recover. It may not be easy to prevent your bird from ingesting metal, due to the wide variety of toxic objects and the natural curiosity of birds.
Can I use a metal bowl for bird bath? ›
Metal Bird Baths & Bowls
They provide birds with fresh clean water as well as a place to bathe and they look great too. Install a metal bird bath bowl in your garden and enjoy the visage of happy birds splashing in the water.
What is heavy metal poisoning in birds? ›
Poisoning from the intake of lead, zinc and occasionally copper is called “heavy metal” poisoning in birds and is one of the most common avian toxicities that we see at our Melbourne Bird Hospital in pet and aviary birds. Birds are often inquisitive and examine new objects and place then in their mouths.
