Is Red Dye Bad for Hummingbirds?

If you've ever bought hummingbird nectar from a store, you've probably noticed it's bright red. That color is intentional — manufacturers add it believing it attracts hummingbirds. But is red dye actually safe for hummingbirds? And do they even need it?

Here's what the science and expert consensus say.

What Is Red Dye #40?

Red Dye #40 (also called Allura Red) is a synthetic food dye made from petroleum. It's widely used in processed foods, candies, and drinks for humans — and it's the same dye used to color most commercial hummingbird nectars.

While Red Dye #40 is FDA-approved for use in human food, that approval doesn't extend to wildlife. Hummingbirds metabolize food differently than humans, and their kidneys and liver process compounds through different pathways.

What Do Ornithologists and Wildlife Experts Recommend?

The consensus among ornithologists and wildlife rehabilitators is clear: there is no reason to put red dye in hummingbird nectar, and good reason not to.

The Cornell Lab of Ornithology, one of the most respected bird research institutions in the world, specifically recommends against using red-dyed nectar. So does the National Audubon Society.

Their reasoning is straightforward: hummingbirds are attracted to the feeder itself, not to red-colored liquid. A red feeder filled with clear nectar works just as well — or better — than a clear feeder with red nectar.

Is There Evidence Red Dye Harms Hummingbirds?

Definitive long-term studies on red dye and hummingbirds are limited, largely because wild birds are difficult to study in controlled settings over time. However, there is documented concern:

Liver and kidney stress. Some wildlife rehabilitators and avian vets have reported that hummingbirds brought in showing signs of illness had been fed red-dyed nectar. While causation is difficult to prove, the pattern has raised enough concern that most experts recommend eliminating the variable entirely.

No benefit, possible risk. Since dye-free nectar performs identically in attracting hummingbirds, there is simply no upside to adding dye — only potential downside.

The precautionary principle. When a substance has no proven benefit for wildlife and carries potential risk, the responsible choice is to leave it out.

What Should Hummingbird Nectar Actually Contain?

Real flower nectar — the kind hummingbirds evolved to drink — is simply sucrose dissolved in water. That's it.

The ideal homemade hummingbird nectar recipe is 1 part white cane sugar to 4 parts water, stirred until dissolved. No boiling required. No red dye. No preservatives.

That's exactly the formulation NectarBloom™ is built around — pure cane sugar, nothing else.

For the exact ratio and method, see our science-backed nectar recipe, and check our feeder cleaning guide to keep that fresh nectar safe. New to feeding? The FAQ answers the most common questions, or try NectarBloom™ 2 lb and measure with the feeder chart.

What About "Natural" Red Dyes?

Some products use carmine (crushed insects) or beet extract to achieve a red color and market themselves as "natural." While these are less concerning than petroleum-based dyes, they still add an unnecessary ingredient to what should be a two-ingredient product.

The cleanest option remains clear, dye-free nectar — which hummingbirds prefer just as much, and which eliminates any dye-related concern entirely.

The Bottom Line

Red dye in hummingbird nectar is unnecessary, potentially harmful, and not recommended by leading ornithological organizations. Hummingbirds don't need it, don't prefer it, and are better off without it.

If you want to do right by the hummingbirds visiting your garden, choose a clean, dye-free nectar made with pure cane sugar — and make sure your feeder has plenty of red on it instead.