Don't offer red dye to hummingbirds

Use clear nectar in your hummingbird feeder

Decades ago, when hummingbird feeders were made entirely of glass bottles, people sometimes added a little red food coloring to the sugar water to attract the birds' attention. Is it OK to use red dye?

Absolutely not. It's totally unnecessary. In fact, research on humans and rats suggests it actually could be harmful.

Today's hummingbird feeders usually have red bases or red nectar ports. They're meant to simulate the red or orange flowers that produce the nectar that hummingbirds value most. That's sufficient to lure the hummingbirds to the feeder. Dyeing the nectar red doesn't add anything beneficial.

What not to do ...

Manufacturers of some hummingbird products add Red Dye No. 40 ("Allura Red AC"), an azo dye made from coal tar, in their nectar powders or fluid. We do not sell these products at The Bird House. The only hummingbird nectar we offer is one containing pure, clear sucrose powder, which you then mix with water. Sucrose is one of the sugars preferred by hummingbirds.

Red Dye No. 40 is used to color candies, drinks, gums, baking mixes, sauces and a host of other packaged foods consumed by humans. For most people, Red Dye No. 40 causes no ill effects. But that may not be the case with all children. Since 2007, scientists at the University of Southampton in England have linked the dye to an increased risk of childhood problems such as attention deficit/hyperactivity disorder, asthma and allergies. In 2001, researchers at the Department of Veterinary Medicine at Iwate University in Japan reported that low doses of Red Dye No. 40 induced DNA damage in the colons of rats.

What are the implications of these studies for hummingbirds that are fed nectar tinted with red dye? No one knows precisely. However, one thing is certain: Hummingbirds consume more dye compared to their body weight than either humans or rats. If the sugar water was colored with Red Dye No. 40, a hummingbird would be taking in 10 times the daily dosage of dye that it took to cause DNA damage among rats in the Japanese study, according to Sheri Williamson, the author of "Attracting and Feeding Hummingbirds" and "A Field Guide to Hummingbirds of North America."

Birds look for the flower's color, as this feeder demonstrates

Another hummingbird expert, Lanny Chambers of Hummingbirds.net, points out that hummingbirds choose nectar by the color of the flower, not the color of the nectar.

"Red dye is unnecessary and contributes absolutely nothing to the good health of a hummingbird," Mr. Chambers says. "It is at best useless. Why take the chance?"

The Cornell Lab of Ornithology strongly recommends against using red dye in feeders.

"There is no research that proves red dye is safe for hummingbirds, and very compelling anecdotal information from experienced, licensed rehabbers that hummers who have been fed dyed food have higher mortality and suffer tumors of the bill and liver," the Cornell experts said.

They emphasize: "Red coloring for hummingbirds? Just say no."