We all want 'hacks' to make life easier — but is adding copper pennies to a birdbath a helpful cleaning tip, or potentially harmful for birds?
Should You Put Copper Pennies in Your Birdbath?
Published on May 02, 2025
If there’s one thing social media apps like TikTok or Instagram have proven, it’s that people love “garden hacks.” We like getting things done the easy way. Who doesn’t want to spend less time cleaning the house, or — in the case of backyard birding — scrubbing out the birdbath? In that context, you might’ve heard of an old “hack” involving putting copper pennies in birdbaths to slow algae growth. Here’s what you should know about adding pennies to your birdbath. Also find out whether copper birdbaths are better than ones made from plastic, glass or stone.
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Do Pennies Slow Algae Growth in a Birdbath?
“Is it safe to put pennies in birdbaths to help limit algae growth?” asks Birds & Blooms reader Megan Long of Red Wing, Minnesota.
Birding experts Kenn and Kimberly Kaufman say, “Over the years, there has been a lot of discussion about using copper to inhibit the growth of algae. While it works to a point, algae eventually will grow in all birdbaths, even if one is made out of copper. Pennies include other metals, and traces of those metals might contaminate the water and could be harmful to birds. To keep your birdbath in a suitable condition for your feathered guests, there’s just no substitute for frequent cleaning.”
Are Pennies Still Made of Copper?
To further elaborate on the point about the metals in pennies, it all has to do with the composition of the coins. Before 1982, contained 95% copper, and 5% zinc. However, in 1982, rising copper prices inspired a change to 97.5% zinc with a copper plating. “One study did express concern that more modern pennies in bird baths can cause concern because of the zinc used,” says Ken Keffer, co-owner of the Wild Birds Unlimited Store in Bloomington, Indiana.
Should You Choose a Copper Birdbath?
Furthermore, Kenn and Kimberly say they would use caution even with birdbaths made from copper. While those products are readily available, it’s difficult to determine what risk they might pose.
“Various studies have tried to determine what concentrations of copper are necessary to cause harm to birds, but they have mostly focused on large birds like chickens or ducks, not on the small songbirds that would use a backyard birdbath,” Kenn and Kimberly say. “We don’t know of any proof that a copper birdbath would be unsafe, but our tendency would be to avoid them, anyway.”
If someone chooses to put out a copper birdbath, Kenn and Kimberly say it’s especially important to change the water with frequency. So a copper birdbath won’t necessarily be less work for you than one made of plastic or glass.
RELATED:
- How to Attract Birds to a Bird Bath
- How (and How Often) to Clean Bird Feeders
- How to Clean Your Hummingbird Feeder
About the Experts
Kenn and Kimberly Kaufman are the official Birds & Blooms bird experts. They are the duo behind the Kaufman Field Guide series. They speak and lead bird trips all over the world, and when they’re not traveling, they enjoy watching birds and other wildlife in their Northwest Ohio backyard.
Ken Keffer is an award-winning environmental educator and author, and a past president of the Outdoor Writers Association of America. He has a degree in wildlife biology, and his career has been spent highlighting the importance of nature and encouraging people to explore the outdoors. He and his wife, Heather Ray, own a backyard bird feeding nature shop.
