Hummingbirds are known for their ability to hover in midair and their fast wing beats. They are also known for their association with brightly colored nectar-producing flowers, leading many people to believe that hummingbirds are attracted to certain colors. But is this really true? Do hummingbirds have color preferences when seeking out nectar sources? In this article, we’ll explore what science tells us about hummingbird vision, color perception, and color preferences.
Hummingbird Vision
Hummingbirds have excellent vision that allows them to see colors very well. They have four types of color cones in their eyes, compared to just three in human eyes. This allows hummingbirds to see into the ultraviolet spectrum, detecting colors that humans can’t see. Having an extra color cone also means that hummingbirds can perceive colors more distinctly than humans can. Their color vision is well-adapted to seeking out nectar-producing flowers.
Hummingbirds rely heavily on their sense of vision when foraging. They have high visual acuity, meaning they can see fine details and detect small movements very well. Their eyes are large relative to their body size, and their retinas are packed with photoreceptors, giving them excellent visual capabilities. Hummingbirds can see near ultraviolet light, visible light, and some near-infrared light. Their broad visual range allows them to differentiate between flower colors and patterns.
Color Preferences
Many people believe that hummingbirds have a strong preference for red flowers or red nectar feeders. This is likely because bright red flowers tend to be very attractive to hummingbirds. However, controlled scientific studies have shown that hummingbirds are actually attracted to a variety of flower colors, not just red.
Research has demonstrated the following color preferences in hummingbirds:
| Color | Level of Preference |
| Red | High preference |
| Orange | High preference |
| Yellow | Moderate preference |
| Green | Low preference |
| Blue | Low preference |
| Purple | Low preference |
| Pink | Moderate-high preference |
While red is highly attractive to hummingbirds, they clearly will visit flowers of many colors. Orange and vivid pink flowers also strongly attract hummingbirds. Green flowers, which often blend into foliage, are less preferred, while blue and purple flowers have low to moderate attractiveness. Overall, warmer, brighter colors seem to be more effective at garnering hummingbird attention.
Researchers believe hummingbirds have an innate color bias that draws them to warm-colored flowers, even though they will learn to visit flowers of many colors. The preference for red is thought to be adaptive, as reddish flowers tend to have higher nectar energy content. Additionally, these warmer colors contrast well against green foliage, making the flowers more visible. Keep in mind that different hummingbird species can show slightly different color biases.
Flower Color and Nectar Content
While flower color is an advertisement to attract pollinators, it doesn’t necessarily tell the whole story about nectar rewards. Many native plants have evolved colors preferred by local pollinators, but flower color doesn’t always equate to higher nectar content. Sometimes non-preferred flower colors still produce ample nectar.
That said, certain flower colors tend to be associated with higher nectar production. Plants pollinated by hummingbirds often produce large amounts of nectar and tend to be bright red, orange, pink or purple. Warm colors like red and orange seem to be reliable indicators of nectar quantity and quality for hummingbirds. Green flowers are more hit and miss.
Hummingbirds will readily adapt and remember flower colors, shapes and locations that provide ample nectar. They have excellent long-term memory and will return to productive feeding locations. While innately attracted to certain colors, hummingbirds also use learning and memory to associate rewards with flower cues.
Flower Petal Patterns
In addition to flower colors, patterns on flower petals can also attract hummingbird attention. Strong contrasts between colors or dark lines radiating from the center of a flower can signal a nectar source to a hummingbird.
Some examples:
– Dark lines or dots on a lighter colored background – the radiating lines on cardinal flower petals that point a hummingbird to nectar.
– Contrasting colors along petal edges – the dark edges of columbine flowers standing out against lighter colored petals.
– Bright “bulls-eye” centers – the vividly contrasting centers of some lilies.
– Spotted or striped patterns – the speckled throats of some fuchsias.
Research indicates hummingbirds detect these lines, edges and organized patterns on flowers just as well as they see the overall flower color. The patterns likely help the birds pinpoint nectar locations.
Flower Shape
The shape of a flower can also influence its appeal and accessibility to hummingbirds. Tubular flower shapes are highly adapted to hummingbird pollination. The narrow, curved tubes protect nectar from unwanted insects but perfectly suit the long, slender beaks of hummingbirds.
Some examples of tubular hummingbird flowers include:
– Trumpet vine
– Coral honeysuckle
– Columbine
– Penstemon
– Fuchsia
Dish or bell shaped flowers are also very attractive to hummingbirds. The wide opening allows easy access. Examples include:
– Cardinal flower
– Trumpet creeper
– Silverbells
– Foxglove
– Salvia
Artificial feeders that mimic the look and function of tubular or bell-shaped flowers do well at attracting hummingbirds. But hummingbirds will visit flower shapes of all kinds to reach nectar, especially if they remember those flowers providing rewards in the past.
Does Flower Color Matter More Than Shape?
Research into hummingbird color and shape preferences indicates that both factors matter, but flower color seems to be more influential in attracting initial interest and driving preference.
In lab experiments studying ruby-throated hummingbirds, researchers found the birds clearly preferred red artificial flowers compared to other flower colors. When given choices between variously colored flowers of the same shape, the birds consistently chose red flowers and rejected green or blue flowers, even if those had higher sugar concentrations.
However, flower shape did make a difference too. When lighter colored tubular flowers were presented along with darker solid or speckled disc flowers, the hummingbirds primarily chose the tubular shaped flowers, seemingly associating the tube with efficient nectar access.
So both factors play a role, but flower color appears to exert a stronger pull on hummingbird attraction and may override shape preferences in some cases. Flower color especially influences initial attraction, but shape can drive preference once the birds learn which forms offer the easiest nectar access.
Flower Location
In addition to flower colors, patterns and shapes, hummingbirds likely take note of where certain flowers are located in order to find productive nectar sources.
Research shows hummingbirds have excellent spatial memory and recall specific locations. They can remember not only where individual flowers and feeders are, but also where dense patches or clusters of flowers can be found.
Some factors that may help hummingbirds pinpoint flower locations include:
– Flower location relative to surrounding landmarks – Hummingbirds may use nearby trees, buildings, or other landmarks to create a mental map and remember locations of flower clusters.
– Position along a feeder circuit – Hummingbirds often follow a regular daily route of nectar sources. The sequence of flowers along this circuit helps reinforce location memory.
– Relation to other flowers – Nearby flower clusters, or being part of a large inflorescence, can help a bird relocate an individual flower.
– Height and position – Flowers at a preferred height, or located outwards on a tree branch, may be easier to find again.
– Visual contrasts – Bright flowers against a dark background, or flowers moving in the breeze, can help hummingbirds spot their locations more easily.
So hummingbirds likely rely on a combination of visual cues including nearby landmarks, spatial relationships, height, background contrasts and movement patterns to remember and relocate favored flower sites.
Role of Scent
While hummingbirds are highly attracted to visual flower cues, they also have a sense of smell that may play a limited role in locating some food sources.
In general, hummingbirds do not have a strong sense of smell compared to some other bird groups. But they do have some modest olfactory capabilities that might assist them in a few specific situations, such as:
– Smelling nectar – in certain flowers, scents may indicate the presence of nectar rewards.
– Scent orientation – in some cases, hummingbirds may orient to strongly scented flowers from a distance.
– Smelling fermentation – the scent of fermenting nectar from succulents, tree sap, etc may draw in hummingbirds.
– Potential pheromone sensitivity – hummingbirds may possibly detect scents from other individuals in some social situations.
While hummingbirds clearly rely much more on sight to locate flowers, a minor olfactory component may supplement visual cues in some cases when seeking nectar rewards. But vision appears to be the primary sense guiding their foraging.
Flower Positioning
To take advantage of hummingbird flower preferences in gardens, consider the following tips on flower positioning:
– Place red, orange, pink or purple flowers where they will stand out against the green foliage as much as possible. Contrasting backgrounds help attract hummingbird attention.
– Position flowers outwards on branches and stems, not hidden amongst leaves, for greater visibility. Hummingbirds prefer flowers extended out in the open.
– Have flower clusters and dense patches rather than solitary individual flowers. Hummingbirds seem to locate and recall groups of flowers more readily.
– Place taller flowers and feeders above eye level – hummingbirds prefer feeding at relatively raised flower positions.
– Allow movement – flowers that sway in the breeze seem to be more visible to hummingbirds.
By keeping their innate color and shape preferences in mind, and maximizing visibility through strategic placement, you can create an attractive environment for hummingbirds in your garden.
Impact of Flower Availability
If fewer flowers of the colors, shapes and orientations that attract hummingbirds are present in a given habitat, hummingbirds may be more likely to visit other flower types they would otherwise ignore.
During times of scarcity such as dry periods that desiccate flowers, hummingbirds may be more responsive to non-typical food sources they wouldn’t normally feed from. For example, when preferred flowers are not available, hummingbirds may visit more green, blue or purplish flowers if that’s all that’s accessible.
Likewise, younger hummingbirds on their first foraging attempts may not exhibit such strong innate color biases. They visit a wider range of flower colors and shapes when learning to locate nectar. With experience, they start to preferentially target flowers matching their evolved visual preferences.
So while hummingbirds generally favor certain colors, shapes and orientations, they can adapt and exploit a wider range of flowers when their favored sources are scarce. Flower foraging strategies remain somewhat flexible depending on floral availability.
Conclusion
In summary, hummingbirds are strongly attracted to certain colors, especially bright warm hues like red, orange and pink, that contrast against foliage. They also respond well to tubular and bell-shaped flowers adapted to their feeding style. While vision is their primary sense used for finding flowers, scent may modestly supplement visual cues in some cases.
Flower location also impacts hummingbird foraging, as they remember locations providing plentiful nectar. Maximum visibility and strategic placement leveraging their innate preferences is key to attracting hummingbirds to your garden. While color plays a major role in hummingbirds’ initial attraction to flowers, they can adapt and exploit a wider range of flowers if availability is limited. By understanding how hummingbirds rely heavily on sight to locate nectar sources, we can better provide an appealing floral environment to attract these unique, charismatic birds.
