Over the years, I cannot count the number of times I have been asked, “Is it safe to feed hummingbirds nectar treated with red food coloring?” I have always said I see no problem with doing so since there is no evidence red food coloring is harmful to the hummingbirds.
I then go on to say since the red food coloring has no nutritive value, why lace sugar water with this food additive in the first place? Its intended purpose is to assist hummingbirds to locate a feeder. The truth of the matter is hummingbirds are attracted to the color of the feeder itself and not the nectar it contains.
This is demonstrated by the fact hummingbirds have no difficulty locating feeders containing clear hummingbird food. In recent years, however, researchers have begun to question whether the red food coloring currently used in some commercial hummingbird food mixes actually poses a health threat to these tiny birds.
The red food dye incorporated in many hummingbird mixes is a petroleum-based product named Red Dye #40. It has been approved for human use in the United States by the Food and Drug Administration.
However, it should be noted this food additive has been banned in Austria, Belgium, Denmark, France, Germany, Sweden, and Switzerland. On top of that, the World Health Organization has set the Accepted Daily Intake (ADI) for humans at a maximum of 7 mg per kg of body weight.
These recommendations are largely based on the results of laboratory trials conducted on mice and rats. These research studies have found that Red Dye #40 causes tumors and cancer and reduces the reproductive rates of the test animals used in the study.
As far as I know, no similar trials have been conducted on hummingbirds. As such, until ornithologists complete research of this subject we have no ways of knowing whether the synthetic dye is indeed harmful to one of our favorite backyard birds.
To date, the only suggestions that Red Dye #40 may be deleterious to the health of hummingbirds stem from observations made by hummingbird rehabilitators. Some of them have reported that when hummingbirds in their care were fed nectar containing Red Dye #40, they seemed to suffer from higher rates of mortality and tumors on their bills and liver than those birds not fed food containing the dye. I emphasize such observations do not constitute clinical trials.
However, one study found that a hummingbird that consumes 10 grams of nectar a day is consuming 17 times more Red Dye #40 than the maximum daily intake recommended for humans.
This and other evidence prompted the prestigious Cornell Laboratory of Ornithology to issue a warning to hummingbird fanciers to refrain from feeding hummingbirds nectar containing the red dye.
I hope that researchers will soon unequivocally determine whether or not Red Dye #40 is harmful to hummingbirds. In the meantime, from now through the end of summer Monroe Countians will be feeding untold gallons of hummingbird nectar to the ruby-throated hummingbirds that will be visiting feeders. Some of this nectar will undoubtedly contain red food coloring. Whether or not any of the food containing Red Dye #40 comes from your backyard is a personal decision. Are you going to offer hummingbirds red nectar this year? I know what I am going to do.
Terry Johnson is retired Program Manager of the Georgia Nongame-Endangered Wildlife Program. He has written the informative column ‘Monroe Outdoors’ for the Reporter for many years. His book, “A Journey to Discovery,” is available at The Reporter. Email him at email@example.com.