Hummingbirds are known for their colorful, iridescent plumage and their fast-beating wings that allow them to hover in midair as they feed on flower nectar. One of the most distinctive features of many hummingbird species is the vibrant red, orange, or pink spot that can be seen on the throat of adult males. This spot is known as a gorget.
The gorget plays an important role in hummingbird communication and behavior. In this article, we’ll explore what a hummingbird’s gorget is, its purpose, how the color is produced, differences among species, and some other interesting facts about these spectacular feathers.
What is a Hummingbird Gorget?
A gorget refers to a patch of iridescent feathers on the throat of adult male hummingbirds of many species. The feathers produce a vibrant splash of color when the light hits them at certain angles. Gorgets come in a range of hues from crimson red to metallic magenta, orange, gold, blue, or green.
The gorget is comprised of modified feathers called plumules that lack barbicels. This lack of barbicels allows the feathers to separate from one another and reflect more light. The effect is magnified by the fact that each plumule has a plate-like structure that contains pigments packed with air bubbles. When light hits these plates, the color is intensified and can appear to change or shimmer depending on viewing angle.
Purpose and Function
A hummingbird’s gorget serves multiple functions:
- Visual Display – The bright color attracts females and serves as a visual display during courtship. Dominant males will flare their gorgets to signal aggression and ward off competitors.
- Species Identification – The size, shape, color, and pattern of the gorget helps identify different hummingbird species.
- Temperature Regulation – By adjusting the angle of the gorget feathers, hummingbirds can better absorb or release heat.
Additionally, some scientists theorize the iridescent gorget may play a role in pollination by attracting insects. The shifting rainbow of colors created by the feathers could mimic the petals of a flower.
How is the Color Produced?
The brilliant iridescent color of the gorget arises from both pigmentation and structural coloration:
- Pigments – The feathers contain pigments like carotenoids, melanins, and psittacofulvins that reflect certain wavelengths of light. Carotenoid pigments produce red, orange, and yellow hues.
- Structural Coloration – The precise nanostructure of the feathers causes light interference and amplification of certain colors by scattering light. The plates in the plumules are spaced just right to reflect a single specific color that depends on the spacing size.
The combination of selective absorption by pigments and manipulation of light by the feather structure allows hummingbirds to produce vivid, shimmery, and metallic gorget colors. The highly specialized plumage took millions of years to evolve into such a precise configuration.
Differences Among Hummingbird Species
There is considerable variation in the appearance of gorgets across the over 300 hummingbird species. Some key differences include:
- Size – Ranging from large patches covering much of the throat to tiny spot gorgets.
- Shape – Can be rounded, elongated, triangular, crescent-shaped and more.
- Color – Spans the spectrum from red, orange, gold, green, blue, purple, black, and white.
- Patterning – Solid, spotted, stripped, or iridescent.
- Metallic or matte appearance.
- Brilliance – Can be intensely saturated or duller pastel versions of colors.
Here are some examples of this diversity:
- Anna’s Hummingbird – Ruby red elongated gorget.
- Costa’s Hummingbird – Iridescent purple forehead and throat patch.
- Rufous Hummingbird – Vivid orange solid throat patch.
- Calliope Hummingbird – Tiny red streaks on a white background.
- Violet-tailed Sylph – Large bright green triangular gorget.
The variety allows different species to signal their identity. Females can also have small gorgets, spots, or streaks. Juveniles lack a gorget until their first molt.
When Does the Gorget Appear?
The brilliant gorget feathers first appear when a male hummingbird reaches sexual maturity after their first molt. This occurs approximately 1 year after hatching. The gorget grows larger and more vibrant during the second year of life and reaches full maturity by year three.
Female hummingbirds may develop small gorgets or spotting after their second molt, but they are not as extensive or colorful as the male gorget. Immature juveniles completely lack gorget feathers until they molt into adult plumage.
The timing of molting varies by species and climate. In temperate regions, hummingbirds molt in the late summer months after breeding season. Tropical species may molt multiple times per year. The new gorget feather growth starts first, followed by replacement of body feathers.
How Are the Gorget Feathers Distributed?
The gorget feathers are strategically arranged to maximize visibility and eye-catching display:
- Positioned on the throat above the beak.
- Situated around the ears and neck.
- Fanned out to catch the light.
- Tilted to reflect at varying angles.
- Higher density of feathers compared to other areas.
Within a gorget, the iridescent plumules are concentrated on the exposed frontal surface, while supportive downy feathers are placed underneath. The lack of skin or blood supply underneath gives the gorget an almost painted on appearance.
When a male hummingbird flares his gorget during courtship, the feathers lift up to display the maximum surface area and intensity of color. This behavior both attracts females and intimidates competing males.
How Do Hummingbirds Spread Their Gorget Feathers?
Hummingbirds have evolved specialized muscles and feathers allowing them to deliberately control the spread of their colorful throat gorgets. Here’s how it works:
- Collar muscles – Thickened collar muscles behind the gorget anchor and control movement of the feathers.
- Flexible quills – Broad, flexible quills at the base allow feathers to hinge and lift up.
- Erectile tissue – Spongy tissue between feathers can fill with fluid to push them apart.
- Weak connections – Lack of barbicels allow the feather vanes to separate and split.
Using these mechanisms, males can quickly flare their gorgets upright into a wide fan shape. This posture makes the patch appear suddenly larger and more visible. The iridescent effect is also most dazzling when the feathers are fanned perpendicular to the light source.
When not flared, the slender feathers lie smoothly flat against the body to allow streamlined flight. So gorgets can instantly transform from covert to conspicuous in seconds!
Do Male and Female Gorgets Differ?
In most species, the male’s gorget plumage is distinctly brighter and more extensive than the female’s:
- Larger size – Can spread over the entire throat and neck region.
- Brighter colors – More vibrant and saturated iridescent hues.
- Defined shapes – Bold circular, crescent, or triangular patterns.
- Uniform appearance – The gorget forms a solid patch of color.
Whereas female gorgets tend to be:
- Smaller – often just a spot or thin streaks.
- Duller – More subdued versions of the male colors.
- Diffuse – Sparse or scattered feathers.
- Camouflaged – helps hide on the nest.
The differences help reinforce species identity and enable mating selection between the sexes. In a few unusual species like the Purple-crowned Fairy, the female actually has a larger and brighter gorget than the male!
Do Juvenile Hummingbirds Have Gorgets?
Young juvenile hummingbirds completely lack a gorget. Their initial downy body feathers do not yet contain the specialized pigments and structural characteristics needed to produce iridescent plumage.
After their first molt into adult feathers at around 1 year old, young males will display the first hints of a gorget. However, the feathers are often scattered and lack a defined shape or intense coloration.
Only after the second annual molt, when the birds are entering their second year, will juveniles achieve the fully formed extensive gorget typical of mature adults. So it takes time for these unique feathers to develop their dazzling hues and patterning.
Can Hummingbirds Control Their Gorget Colors?
While hummingbirds can dynamically spread their gorgets, they cannot instantly or consciously change the actual colors being displayed. The hues produced by the feathers are fixed by the combination of:
- Pigments – The types and densities of carotenoids, melanins, and other pigments within each feather when it developed.
- Structural components – The precise nanoscale architecture of the air bubbles and plates in each feather.
These factors impart a genetically predetermined color that cannot be altered at will. However, there are some ways gorget color can shift slowly over time:
- Molting – New feathers may incorporate different pigments.
- Feather wear – Scratches and cracks disrupt structural colors.
- Oxidation – Chemical changes can modify pigment hues.
- Diet – More carotenoids may produce redder feathers.
So while gorget color is not instantaneously controllable, males can still dynamically catch the eye of females by rapidly fanning their feathers into a striking display.
Do Hummingbirds Have Ultraviolet Gorget Colors?
Research has revealed several hummingbird species also utilize ultraviolet (UV) plumage regions that are invisible to human eyes but visible to avian vision. These include:
- Black-chinned Hummingbird
- Broad-tailed Hummingbird
- Rufous Hummingbird
- Costa’s Hummingbird
- Calliope Hummingbird
In most cases, the UV reflectance occurs right in the gorget region. The combination of UV with visible colors enables hummingbirds to display a richer and more nuanced range of hues for courtship, competition, and species recognition.
Specialized feathers with nanostructures tuned to reflect UV wavelengths in addition to visible light allow hummingbirds to take advantage of avian tetrachromatic vision and see a world of color humans can barely imagine!
Conclusion
A hummingbird’s gorgeously iridescent gorget serves many important functions related to communication, courtship, competition, and expression of identity. The highly specialized plumage took millennia to evolve through intricate pigment chemistries and structural modifications that amplify and manipulate light reflection.
While humans can only appreciate the visible spectrum colors produced by the feathers, hummingbirds themselves also utilize UV colors and patterns we cannot perceive. By dynamically controlling their feathers with specialized muscles and flexibility, males can strategically display their gorgets to impress females and outshine competitors. The variations in size, shape, and color of gorgets help distinguish the over 300 different hummingbird species from one another.
So next time you catch a glimpse of a hummingbird’s throat, appreciate that each flash of brilliant color represents an incredible evolutionary achievement. These tiny birds have developed some of the most advanced and visually stunning plumage in the animal kingdom!