Hummingbirds are known for their ability to hover in midair and their attraction to flowers, especially red ones. But why are hummingbirds so drawn to the color red? The answer has to do with the anatomy and feeding behaviors of hummingbirds.
Hummingbirds Have Excellent Color Vision
Hummingbirds have some of the best color vision among all birds. They have four types of color cones in their eyes that allow them to see ultraviolet light as well as the red, green, and blue light visible to humans. This gives hummingbirds a very wide range of color perception.
The ability to see in the ultraviolet spectrum allows hummingbirds to spot flowers that humans cannot. Flowers have ultraviolet “nectar guides” on their petals that act as landing strips for pollinators by contrasting with the rest of the flower. These ultraviolet guides are invisible to humans but shine like a beacon for hummingbirds, helping them pinpoint flower centers.
Red Flowers Stand Out Most to Hummingbirds
While hummingbirds can perceive a wide spectrum of color, they are particularly attracted to red. Red emanates strongly in the shades of light that hummers can see. Bright crimson flowers will stand out strongly against green foliage to a hummingbird.
Red flowers also increase in intensity when moving from human visible light into the ultraviolet spectrum, creating an even stronger visual signal for hummingbirds. Additionally, the pigment that makes flowers red, called anthocyanin, is associated with higher nectar production. So red flowers tend to be energy-rich food sources for hummingbirds.
Hummingbirds Have a High Metabolism
Hummingbirds need a lot of calories to support their high metabolisms. At rest, a hummingbird’s heart rate can be over 500 beats per minute. To fuel their hearts and sustain their ability to hover and fly, hummingbirds eat frequently throughout the day.
Their diet is mostly liquid—they get most of their calories from flower nectar and tree sap. Hummingbirds consume between 4-8 times their body weight in nectar each day and visit hundreds or even thousands of flowers daily. They prefer flowers with higher sugar concentrations in the nectar to get more energy-rich food.
Red Flowers Signal sweeter Nectar
Studies have shown that hummingbirds do associate the color red with sweeter nectar. This is because red pigments produced by certain floral plant species actually indicate higher sugar content. Usually red coloration coincides with higher anthocyanin content in flowers, and anthocyanins attract more pollinators by increasing the sugar content.
So when a hummingbird sees a bright red flower, it sends the message that the flower will provide a concentrated hit of energy. The high metabolism of hummingbirds causes them to favor red flowers, seeking out the sweeter payoff they provide.
Red Also Helps Attract Hummingbirds from Farther Away
The bright, striking red of some flowers can be seen from a greater distance than most other flower colors. This allows hummingbirds to spot clumps of red flowers and selectively target those areas, maximizing their foraging efficiency.
Some species of red flowers also advertise themselves by growing on tall inflorescences, which makes them highly visible. Hummingbirds can save energy by focusing in on red flowers that broadcast themselves widely across a habitat.
| Flower Color | Visibility Distance (feet) |
|---|---|
| Red | 1000 |
| Orange | 600 |
| Yellow | 100 |
Red Flowers Indicate Coevolution with Hummingbirds
Some red flower species have actually coevolved with hummingbirds over time to specially appeal to them as pollinators. These flowers have adapted their shapes, scents, and nectar chemistry to attract hummingbirds.
The South American shrub fuchsia has double red petals that function exactly like a hummingbird feeder. Hummingbirds in turn spread the pollen of these red flowers from plant to plant. Both the red flower color and form of these plants have been naturally selected to appeal specifically to hummingbirds.
Hummingbirds Associate Red with Flower Nectar
Research indicates hummingbirds learn to identify flower colors through experience foraging. Young fledgling hummingbirds visit flowers at random initially. But they start to preferentially focus on flowers that offer nectar rewards.
When red flowers consistently provide sweeter nectar, hummingbirds learn to seek them out over other flower colors. This suggests an element of conditioning and learning is involved in hummingbirds’ attraction to red.
Differences Based on Geographic Location
Hummingbirds’ preference for red isn’t uniform across all species and habitats. Some kinds of hummingbirds appear to be more specialized around feeding at red tubular flowers, while others are less selective.
There are also regional differences in favorite flower colors. Hummingbirds in North America heavily favor red flowers, while hummingbirds in the tropics also readily visit other bright colors like orange, yellow, and purple. This shows an interplay between plant life, flower adaptations, and hummingbird behavior based on ecosystem.
Advantages of Red Flower Association for Hummingbirds
There are some key advantages hummingbirds gain from seeking out red flowers:
- Red flowers tend to advertise sweeter nectar content that provides more energy.
- Red is highly visible and can be seen from farther away, improving foraging efficiency.
- Red flowers often contain more hummingbird-friendly adaptations in shape and orientation.
- Red flowers build an association between color and nectar rewards through learning.
By targeting red flowers, hummingbirds are able to maximize their foraging energy intake. This crucial energy helps hummingbirds power their metabolically taxing hovering flight and active lifestyle. Associating red with sweet nectar rewards helps hummingbirds fulfill their substantial daily energy needs.
Conclusion
Hummingbirds’ strong attraction to red ultimately stems from their specialized diet and extreme metabolism. To meet their high energy needs, hummingbirds seek out flower colors associated with sweeter nectar. Red flowers tend to be energy-rich and highly visible, signaling sweet payoffs. Hummingbirds preferentially feed from red flowers across most habitats, likely both innately and through learned association. This allows hummingbirds to efficiently find the calories they need to keep their wings rapidly beating and sustain their intense lifestyle. Bright red flowers and busy hummingbirds demonstrate an intriguing example of colorful coevolution between plants and pollinators.
