Hummingbirds have an extremely high metabolic rate, requiring them to constantly seek out high-calorie nectar sources. Because their survival depends on quickly locating these food rewards, their feeding behavior is profoundly driven by visual cues, making color a primary signal in their search for sustenance.
The Dominant Color Preference
Hummingbirds are powerfully attracted to colors at the warmer end of the visual spectrum, such as vibrant red, bright orange, and intense pink or magenta. This preference often overrides other senses, as hummingbirds have a poor sense of smell.
While red is the most recognized attractant, the intensity of the color is often more important than the specific hue. A bright, high-contrast patch of color will catch a hummingbird’s eye much faster than a duller one. This visual acuity allows them to efficiently target potential food sources from a distance against green foliage.
The Science Behind Hummingbird Vision
The foundation of the hummingbird’s color preference lies in its specialized anatomy, which differs significantly from human eyes. Humans are trichromats, possessing three types of cone cells to perceive color. Hummingbirds, however, are tetrachromats, having a fourth type of cone cell that extends their vision into the ultraviolet (UV) spectrum.
This fourth cone allows them to perceive a massive range of colors invisible to the human eye. They can see combinations of light that we cannot, known as non-spectral colors, such as UV+red, UV+green, and pure UV.
Their visual system is particularly sensitive to long-wavelength colors like red, which is a result of a greater concentration of specialized cone cells in their retinas. This biological makeup gives them a heightened ability to detect and differentiate colors in the red and yellow range. Researchers have demonstrated that wild hummingbirds can easily distinguish between two colors that look identical to a human, proving their superior color discrimination is used in their daily foraging.
Color Signaling and Ecological Association
The strong preference for red and red-adjacent colors is rooted in a co-evolutionary relationship with flowering plants. In many environments, bright red and orange colors signal a flower that contains a high concentration of sugar, representing a rich energy reward. This color acts as an advertisement for the bird.
Flowers that are pollinated by hummingbirds, known as ornithophilous flowers, often display these warm colors because they are generally less attractive to common insect pollinators like bees. Bees often overlook red flowers due to their different visual sensitivities, which reserves the plant’s valuable nectar for the hummingbird.
Hummingbirds are not born with a fixed attraction to red, but their advanced vision allows them to quickly learn and reinforce this preference. Once a bird successfully feeds from a red flower, that memory is stored, and the color becomes a reliable signal of food. The contrast of a red flower against the green background of leaves makes this signal highly effective.
Practical Application: Feeders and Nectar Safety
When attempting to attract these birds, the color principles can be applied directly to artificial feeders. The feeder itself should incorporate bright red or orange elements, such as the feeding ports or base, to catch the bird’s eye. However, the liquid nectar placed inside the feeder should remain clear.
It is strongly advised never to add artificial red dyes or food coloring to the sugar water. Natural flower nectar is clear, and the dye is completely unnecessary for attraction since the red parts of the feeder already perform that function.
Because hummingbirds have an extremely high metabolism, they consume large quantities of nectar relative to their body size, potentially ingesting very high concentrations of the dye. Although formal studies are lacking, licensed wildlife rehabilitators have reported concerns that the chemicals may cause serious health issues. A simple solution of one part white cane sugar to four parts water is the safest and most effective nectar recipe.