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Hummingbirds run on sugar.
Sweet nectar powers their tiny, furious bodies and super-fast wings, which beat as many as 80 to 90 times per second. And luckily for them, they don’t seem to get diabetes, even though they have extremely high blood glucose levels.
In the wild, hummingbirds, the smallest birds in the world, get their sugar from wildflowers, such as honeysuckle, lilies, and bee balm. But following the sweeping destruction of native prairies, forests, and wetlands over the last century, these fluttering jewels have had a more difficult time finding their glucose fix. Warming linked to climate change is also making flowers bloom earlier and changing the range of some hummingbird species, making it even harder for the birds to feed.
While humans are, of course, responsible for these impacts, some wildlife lovers are also trying to help — by installing feeders. Often red and plastic and filled with sugar water, hummingbird feeders provide a supplementary source of nectar for hummingbirds, especially during fall and spring migration when the birds are traveling long distances. Research shows that feeders may increase the number of hummingbirds locally, and birds tend to visit them more when there are fewer flowers in bloom.
So on the whole, feeders are good. They also provide an easy way for people to connect with wildlife.
But there’s one big, big, caveat here: If your feeder is dirty, it could be harming, or even killing, the hummers that visit it, turning the feeder from a lifeline into a trap. Unless you’re prepared to regularly clean your feeder, you may be better off not having one.
Dirty feeders can be deadly
The problem is simple: If sugar water is left out too long, it will spoil, meaning it will attract and grow microbes. Some of those microbes are bad and can cause infections, including candida — a type of yeast that causes yeast infections in humans and, apparently, in hummingbirds.
When hummers contract fungal infections, their tongues swell and become difficult to retract. That can put them at risk of starvation. Infected birds also sometimes appear with lesions on their beak or more generally lethargic, said Melanie Furr, a licensed wildlife rehabber who works with Wild Nest Bird Rehab in Georgia.
One study published in 2019 found that most microbes in feeders are not dangerous to hummingbirds. And it’s unlikely that dirty feeders are causing population-wide declines of birds, said Don Powers, a professor emeritus at George Fox University who’s studied hummingbirds for decades.
But it’s still “fairly common” for individual birds to be sickened by them, Furr told me.
“I think it boils down to the fact that most people are not cleaning their feeders or refreshing their nectar as often as they should,” she said.
Other wildlife rehabbers have similarly indicated that many adult and baby hummingbirds are in need of rescue because of feeder-related infections. Furr says antifungal medication can clear up the infection and make them healthy enough for release.
Just as the problem is simple, the solution is thankfully simple, too.
How to set up and clean a feeder
There are two key components to a healthy hummingbird feeder: the right recipe and regular cleaning. Both are incredibly straightforward.
Mix 1 part refined white sugar with 4 parts drinking water, such as ¼ cup sugar with 1 cup water. Dissolve over heat and cool.
- Don’t use other kinds of sugar or sweetener.
- Avoid red food coloring, including store-bought nectar with artificial color.
- Purified water is better. Avoid distilled water, Furr said, because it lacks trace minerals that birds need.
- You can refrigerate unused nectar for up to two weeks.
In spring and fall, you should clean your feeder every two to three days. In the summer — or whenever it’s hot — you should clean the feeder daily or every other day, Furr said.
“If you wouldn’t leave your drink sitting out in the sun for three days and then drink it, don’t do it for hummingbirds,” Furr said. “Why should a little, 3-gram hummingbird be expected to survive whatever germs are growing there?”
If you’re changing out the nectar every few days, you can simply clean the feeder with hot water, she said. But if it’s been a while, or you see or smell mold, scrub it down with a mixture of vinegar and water or using hydrogen peroxide. You should also make sure the feeder is completely dry before refilling it to prevent bacteria from growing, said Chad Witko, specialist in avian biology at the National Audubon Society.
“If you’re going to commit to keeping it clean, it’s a great idea,” Furr said of feeders. “Hummingbirds, like birds across every biome, are in decline. Habitat loss and lack of native plants present challenges to them. Having a clean feeder can provide an additional food resource that can be important.”
Level up your hummingbird support
Don’t want to bother with cleaning? Or want to do more for your local hummers?
Consider planting native hummingbird-friendly wildflowers. The National Audubon Society has a tool that tells you what to plant in your region to attract hummingbirds.
And lastly, if you do come across an injured hummingbird, contact a local wildlife rehabber. This website is a good place to start.
Update, June 10, 2:35 pm ET: This article has been updated to include additional information about the risk of dirty hummingbird feeders.
