The Anna’s hummingbird (Calypte anna) is a small, iridescent green and pink bird found along the west coast of North America. Known for its remarkable speed and aerial agility, this flashy bird zips through the air like a tiny fighter jet. But what are the exact colors that give the Anna’s hummingbird its distinctive look?
Iridescent Throat and Crown
The most vibrant colors on the Anna’s hummingbird are found on the male’s head and throat. When the light hits just right, these areas burst into a spectacular iridescent rose-pink or magenta color. This iridescence is created by specialized feather structures that refract light. By changing the angle of the feathers, the hummingbird can alter the wavelengths of light that are reflected, leading to a shimmering, rainbow effect.
In poor lighting conditions, however, the iridescence disappears and the male’s throat and crown appear dark gray. This color change allows the birds to become less conspicuous in low light. Females and juvenile males lack iridescent feathers, appearing more gray-green on the head and white on the throat.
Green Back and Tail
The Anna’s hummingbird’s back and tail are covered in bright green feathers. These feathers do not display iridescence like the throat and crown. Instead, their color comes from pigments within the feathers. The green hues help camouflage the birds when perched among trees and vegetation.
One unique characteristic of the tail feathers is that the outer three pairs are tipped with white. This creates a distinctive pattern when the tail fans out during flight. The white-tipped pattern is present on males, females, and juveniles.
Red-Purple Gorget
Some male Anna’s hummingbirds develop a vibrant red-purple band of color, known as a gorget, on the lower half of the throat. The gorget varies in shape and intensity between individuals. When the gorget is particularly large and vivid, it is referred to as a “beard.”
Research indicates that the presence and brightness of the red-purple gorget signals dominance and fitness to female hummingbirds. Older males tend to have larger and brighter gorgets than younger males. Females and juveniles do not have a pronounced gorget.
Variations by Age and Range
The Anna’s hummingbird displays some slight variations in plumage color across different age classes and geographical ranges:
- Females and juvenile males have grayish heads and crowns rather than iridescent pink and may lack gorget feathers.
- Males in the northern parts of the range (such as Canada and Alaska) typically have more extensive iridescent magenta on the crown.
- Birds in the southern range (California and Arizona) more commonly display red-purple gorget feathers.
Diet Influences Color
Researchers have found that the diet of Anna’s hummingbirds influences feather color and iridescence. Hummingbirds obtain carotenoid pigments from the nectar and insects they eat. These pigments are absorbed into the bird’s feathers and skin, intensifying orange and pink iridescent colors.
Lab experiments showed that male Anna’s hummingbirds fed a carotenoid supplement grew much brighter, redder gorgets than males on a control diet. This demonstrates that access to carotenoids directly impacts the bird’s colors and may provide a competitive advantage.
Color Patterns and Functions
The striking pink and green plumage of the male Anna’s hummingbird likely serves multiple functions:
- Attracting mates – Females are attracted to males with the largest, brightest gorget and crown patches, indicating fitness.
- Competition with males – Intense male colors signal dominance in competition over flowers, feeders, and mates.
- Camouflage – Greens and grays allow the birds to blend into vegetation when not displaying.
- Thermoregulation – Dark iridescent feathers may help absorb heat from sunlight.
Color Spectrum
While human eyes perceive the Anna’s hummingbird’s main feather colors as shades of green, gray, pink, and purple, these birds see an even broader spectrum of color. The Anna’s hummingbird has tetrachromatic vision, meaning they have four color cones in their eyes that allow them to see into the ultraviolet range.
When illuminated with UV light, many of the hummingbird’s feathers give off a strong UV signal, creating patterns unseen by humans. This additional dimension of color may provide important cues for mate selection and competition.
Summary
In summary, the key feather colors of the male Anna’s hummingbird are:
- Iridescent magenta or pink throat and crown
- Bright green back and tail with white tips
- Red-purple gorget patches (variable)
The coloring comes from both pigments as well as structural iridescence. Diet, age, range, and lighting conditions all impact the bird’s precise hue and saturation. The striking plumage plays an important role in courtship, competition, camouflage, and heat regulation. By seeing an expanded range of color, these tiny birds encounter a visually rich world.
Feather Area | Color | Notes |
---|---|---|
Crown and throat | Iridescent magenta/pink | Iridescent color from feather structures. Brightest on older males. |
Nape, back, and tail | Green with white tips on tail | Pigment color not iridescent. Provides camouflage. |
Partial gorget | Red-purple | Pigment color that signals fitness. Variable by age and range. |
Influences on Color
- Age – Younger birds have less iridescent color.
- Diet – Carotenoids increase pink and red hues.
- Geographic range – More red in south, more magenta in north.
- Light exposure – Iridescence disappears in low light.
The vibrant and complex coloration of the Anna’s hummingbird provides insight into the form and function of avian plumage. This tiny bird displays an astonishing array of hues and color-shifting feathers exquisitely tuned to the challenges of courtship, competition, camouflage and aerial agility.