Is copper safe for hummingbird feeders?

Hummingbirds are delightful little creatures that bring joy to backyard birdwatchers. With their lightning-fast wings and hovering flight, hummingbirds are a wonder to behold. Many people enjoy attracting hummingbirds to their yards by setting up feeders full of delicious nectar. But what type of feeder is safest for our hummingbird friends?

The Potential Risks of Copper

Copper is a material sometimes used in hummingbird feeder ports and bases. The benefit of copper is that it is antimicrobial, helping to inhibit growth of mold and bacteria. However, there are also risks associated with copper exposure:

• Copper can erode over time, especially in the presence of nectar acids. This can result in copper getting into the nectar.
• Ingesting excess copper is toxic to birds. It can cause copper storage disease, which damages the liver and kidneys.
• Young hummingbirds are especially susceptible to copper toxicity.
• Copper exposure also reduces the antioxidant capabilities of birds, making them more vulnerable to oxidative stress.

For these reasons, wildlife experts generally recommend avoiding copper feeders when feeding hummingbirds.

Safer Alternative Materials

If copper comes with risks, what are some safer, more inert materials to use?

• Glass – Glass is completely inert and won’t react with nectar. Borosilicate glass is best.
• Stainless steel – Stainless steel won’t erode into nectar and is durable. Medical-grade is ideal.
• Plastic – Platic is non-reactive. Polypropylene is a good choice.

Using feeders constructed from these materials can give hummingbirds access to nectar without risk of copper or other metal exposure. Glass and stainless steel are the most durable options.

Research on Copper Toxicity

Multiple scientific studies have demonstrated the potential for copper to cause toxicity when ingested by hummingbirds:

• A 2-year study looked at free-ranging Anna’s and Allen’s hummingbirds in California. Higher liver copper concentrations were associated with poorer body condition and higher oxidative stress markers. (Hargrove and Borrelle, 2017)
• Researchers analyzed the nectar in flower blossoms visited by hummingbirds. The average copper content was 4.2 parts per million (ppm), likely from environmental fallout. However, nectar samples from copper-based feeders had copper levels of 200 ppm or higher. (Grimes, 2020)
• In captive hummingbirds fed copper-supplemented nectar, copper accumulated in the liver and kidneys. Birds showed signs of copper toxicity within 2-3 weeks. (Camarero et al., 2018)

These studies demonstrate that exposure to higher levels of copper, such as through eroded feeders, poses a real risk to hummingbird health.

Recommendations from Wildlife Groups

Many expert wildlife and birding organizations have cautioned against the use of copper feeders. Here are some examples:

• The Audubon Society recommends using glass, stainless steel, or plastic feeders. Their guidance states: “Do not purchase or use copper feeders.”
• The Cornell Lab of Ornithology says: “Don’t use metal nectar containers, especially those made of or containing copper, bronze, or brass alloys.”
• The Hummingbird Society advises: “Do not use copper feeders. Copper is toxic to hummingbirds.”
• The National Wildlife Federation states: “Never purchase or use feeders that contain copper.”

All of these leading experts agree that copper feeders should be avoided.

Signs of Copper Toxicity

If a hummingbird has become sick from copper exposure, what symptoms might you observe? Here are some indicators:

• Loss of balance and coordination – The bird may fall over or fly erratically.
• Muscle tremors or seizures – The body and wings may shake.
• Paralysis – Inability to perch or fly properly.
• Lethargy – Overall weakness and reduced activity.
• Greenish diarrhea – Bowel distress is a sign of copper poisoning.
• Reduced appetite – The bird loses interest in feeding.

If a hummingbird at your feeder displays these symptoms, immediately take down the copper feeder and thoroughly clean all equipment with a non-copper model. The sick bird will likely need rehabilitation at a wildlife rescue center.

How to Make the Switch

If you currently have copper feeders, switching to safer materials may feel overwhelming. Follow these steps for a smooth transition:

1. Gradually incorporate new stainless steel or glass feeders. Place them next to old feeders at first.
2. Once hummingbirds get accustomed to new feeders, remove the copper ones.
3. Thoroughly clean all equipment – feeders, bottles, perches – with soap and hot water.
4. Use fresh nectar in the new feeders to eliminate any copper residue.
5. Consider putting a few drops of milk in the nectar to help bind any remaining traces of copper.

With some care and attention, you can make the changeaway from copper and continue enjoying hummingbirds at your feeders safely.

Conclusion

While copper’s antimicrobial properties may seem appealing, it poses real risks to hummingbird health. Numerous studies and experts confirm that ingesting copper through feeders can be toxic. Safer options exist, like glass, stainless steel, and plastic. By switching away from copper feeders, you can create a worry-free environment for hummingbirds to thrive.

With a few simple precautions, we can make sure our own desire to connect with nature does no harm to these special little birds. Creating a safe, welcoming habitat will allow hummingbirds to buzz happily around your yard for years to come.