Hummingbird food, often called nectar, is a simple solution designed to mimic the natural sucrose content found in flowers. The mixture is nothing more than refined white sugar dissolved in water. However, commercial products often feature a vibrant, unnatural red color. This coloration leads many people to believe the dye is necessary for attracting the birds. This article explores the science behind the hummingbird’s attraction to color and investigates the safety of the red dye frequently added to these commercial products.
The Role of Color in Hummingbird Attraction
Hummingbirds possess a highly developed visual system, which is far more complex than human eyesight. Their retinas contain four types of cone cells, whereas humans only have three, allowing them to perceive light in the ultraviolet spectrum. This advanced vision gives them a heightened sensitivity to the warmer end of the color spectrum, making bright hues like red, orange, and yellow stand out. This preference for red is an evolutionary adaptation linked to their natural food sources. The birds have learned to associate the sight of red or orange with an abundant, high-sugar nectar meal, helping them efficiently locate food in the wild.
The Truth About Red Dye in Commercial Feed
The reason commercially prepared hummingbird nectars are red is not to benefit the bird but to appeal directly to the human consumer. Manufacturers add the artificial coloring to align with the assumption that the nectar itself must be red to attract the birds. This marketing strategy capitalizes on the public’s knowledge that hummingbirds are drawn to the color red. The dye most commonly used is Red Dye #40, a synthetic colorant derived from petroleum products. Natural flower nectar is completely clear, and birds will readily visit a clear sugar-water solution, proving the red coloration is unnecessary for attraction.
Health Implications of Artificial Red Dyes
Concerns about the safety of artificial red dyes stem from the fact that these chemicals are not naturally occurring and add no nutritional value. Although no large-scale scientific studies have specifically focused on the long-term effects of these dyes on hummingbirds, there is evidence suggesting potential harm. The base chemical for Red Dye #40, a petroleum derivative, has been linked to concerning health issues in laboratory mammals, including being identified as carcinogenic and mutagenic in rats and mice.
The small size and high metabolism of hummingbirds mean they consume a disproportionately large amount of nectar daily relative to their body weight. A typical hummingbird can consume 10 grams or more of nectar solution per day. If that nectar contains artificial dye, the bird may ingest a concentration estimated to be up to 17 times the maximum acceptable daily intake recommended for an adult human.
Wildlife rehabilitators have anecdotally reported observing higher mortality rates and health problems, such as tumors on the bill and liver, in birds fed dyed nectar. The dye has also been noted to stay in the bird’s system long after consumption, visible in their feces for over 24 hours, indicating a prolonged exposure to the chemical.
Making Safe and Effective Nectar
The safest and most effective nectar solution is a simple mixture of one part refined white sugar to four parts water. This ratio closely mimics the sugar concentration found in the flower nectar that hummingbirds consume in nature. The sugar should be completely dissolved in the water, which can be done by stirring or briefly heating the water, and the solution must be cooled before being placed in the feeder. Using a clear, undyed solution is the preferred method to eliminate the risk of introducing harmful chemicals. To provide the necessary visual cue, select a feeder that incorporates red plastic or glass on its exterior parts, making the dye in the liquid completely obsolete. Feeders should be cleaned thoroughly every two to three days, or even daily in hot weather, to prevent the growth of mold or fermentation.