Quick Answer
Yes, hummingbirds throats can change color. The colors are produced by iridescent feathers called gorgets. Depending on the angle and lighting, the gorgets can appear different colors. When courting, male hummingbirds will fluff their gorgets to display more vibrant colors to females.
Hummingbirds are known for their beautiful, iridescent plumage. One of the most striking features of some hummingbird species is the colorful gorget feathers on their throats. These feathers can flash brilliant reds, oranges, blues and greens. But many observers wonder – do the throat feathers physically change color or is it an optical illusion caused by the lighting and angle? Here we’ll explore the structure of gorget feathers and how they produce color in hummingbirds.
What are gorgets?
A gorget refers to a patch of specialized iridescent feathers on a hummingbird’s throat. The shape, size and coloration of gorgets vary greatly between the over 300 different hummingbird species. Gorgets appear to rapidly change color when light hits them at different angles. This property helps attract mates and establish dominance.
Some common North American examples:
– Ruby-throated Hummingbird – males have bright red gorgets. Females lack a gorget.
– Anna’s Hummingbird – males have vivid rose-pink gorgets that can appear red or orange. Females have small red-spotted gorgets.
– Costa’s Hummingbird – males have striking violet-blue gorgets that shift to magenta. Females have smaller white and gray spotted gorgets.
How do gorget feathers produce color?
Unlike typical feathers that contain pigments, gorget feathers lack pigment. Instead, their structure causes interference and refraction of light that produces iridescent color. Here’s how it works:
– The surface of gorget feathers contain stacked plates separated by microscopic spaces of air.
– When light hits the plates, some wavelengths get reflected back while others get canceled out through destructive interference.
– As the viewing angle changes, the path of light and interference patterns shift, causing different wavelengths of color to be reflected back.
– The shape and spacing of the plates determines the specific colors produced. For example, plates spaced close together produce shorter wavelengths like blue and green.
This complex structure allows gorget feathers to flash multiple colors quickly as the bird moves. The iridescent effect is similar to what’s seen on soap bubbles or the surface of CDs.
Do gorget colors physically change?
So do hummingbird gorgets actually change color or is it just an optical illusion? The answer is they do not physically alter their structure or pigmentation to display different colors. However, males can manipulate their gorgets to display brighter, more saturated colors during courtship. Here’s how:
Fluffing feathers
In their relaxed state, gorget feathers lie flat against each other. This causes more light to be absorbed, muting the iridescent display. However, males can fluff out their gorget feathers so they become more separated and aligned. This allows more light to hit each feather surface and enhances the iridescent effect. So while the feathers don’t change physically, fluffing changes the optical properties to display bolder, more vibrant colors.
Positioning
Hummingbirds can also manipulate how their gorget appears by adjusting the angle and position relative to light sources and observers. For example, a male may orient himself so the sun directly hits his gorget, maximizing the iridescent glow. When courting, he may turn and dip to find the best lighting angle to impress the female.
Why do hummingbirds have colorful gorgets?
What’s the reason behind male hummingbirds evolving these elaborate, light-manipulating feathers? Two key functions likely drove this adaptation:
Attracting mates
In most hummingbird species, females select a mate based on the appearance of the male’s gorget and courtship display. More vibrant, “flashier” gorgets and displays tend to be preferred by females. So over time, evolution likely selected for fancier structural colors in gorget feathers as those males reproduced more.
Establishing dominance
The colors also help males establish a hierarchy. Males will assert their dominance by aggressively displaying their gorget during chases and close encounters. The most dominant male with the brightest gorget typically claims the best feeding territory. Less dominant males are chased away.
Differences between male and female gorgets
As mentioned before, male and female hummingbirds often have dramatically different looking gorgets:
| Male gorget | Female gorget |
|---|---|
| Large and colorful | Small and relatively plain |
| Many iridescent feathers | Fewer iridescent feathers mixed with typical feathers |
| Fluffed out during displays | Lies flat |
This sexual dimorphism suggests gorgets play an important role in courtship and competition in males, but may not serve the same purpose in females. While female gorgets are less elaborate, they may still contribute to species and mate recognition.
Other colorful plumage
While gorgets are the most conspicuous, other feathers on the head, back, wings and tail may also contain specialized structures that produce iridescent colors. However, these feathers generally don’t change orientation and angle like the gorget. Still, this iridescent plumage likely adds to the overall dazzling display during courtship. The precise mix of gorget color and accenting plumage colors helps attract mates and rivals of the same species.
Do young hummingbirds have adult gorgets?
Young hummingbirds don’t initially have the same elaborate gorgets as adult males. Their first set of feathers lacks the complex microscopic structures that produce iridescence. However, after the first molt, they begin to acquire some iridescent throat feathers. By the second year, the gorget is typically fully developed with the radiant colors of adulthood. The transformation allows young males to take part in courtship displays and establish feeding territories.
Conclusion
In summary, hummingbird gorgets utilize specialized feathers to produce iridescent color through the physical principles of thin film interference and refraction of light. While gorget feathers don’t contain pigments or change their structure, males can manipulate them to display bolder, more saturated colors during courtship displays. This ability likely evolved to help attract mates and establish dominance. So in reality, hummingbird gorgets don’t physically change colors – it just appears that way based on lighting and viewing angle. Their incredible back feathers simply allow them to dynamically access a hidden spectrum of dazzling colors.
