The red on cedar waxwings refers to the bright red tips on the secondary flight feathers of these striking birds. Cedar waxwings are medium-sized songbirds that are native to North and Central America. They get their name from the waxy red tips on their wings that look like sealing wax.
The red tips are found on the secondary flight feathers, which are the shorter feathers closest to the body on the bird’s wings. The red color comes from pigments obtained through the birds’ diet of berries. The exact purpose of the red tips is not definitively known, but some theories suggest they may play a role in social signaling and mate selection.
What Causes the Red Tips?
The red color of cedar waxwing wing tips comes from carotenoid pigments obtained through the birds’ berry-heavy diet. Carotenoids are natural pigments produced by plants that create red, orange, and yellow colors.
Common berries eaten by cedar waxwings that provide carotenoids include:
- Juniper berries
- Serviceberries
- Hawthorn berries
- Holly berries
- Dogwood berries
- Sumac berries
- Viburnum berries
These pigments are absorbed into the cedar waxwing’s liver and then deposited into growing feathers. The carotenoids are structurally modified and concentrated in the tips of the secondary flight feathers, creating the vivid red color.
Carotenoid Concentration
Research has shown that the degree of redness correlates to the concentration of carotenoids in the feather tips. Birds with diets higher in carotenoid-rich berries during molting periods when feathers are replaced have brighter red tips.
The carotenoid pigments are not produced by the bird itself, so they must be continually obtained through the diet. The red color will fade over time if the diet lacks sufficient fresh berries.
Theories on the Purpose of the Red Tips
There are a few leading theories as to why cedar waxwings have these bright red wing tips:
Social Signaling
The vivid red tips may play a role in communication and signaling within waxwing social groups. The degree of color may indicate age, social dominance, or fitness to potential mates. Older birds tend to have richer, brighter red.
Flock Cohesion
The red tips are highly visible during flight. This may help waxwings keep track of flock members and maintain cohesion when flying between food sources.
Confusion of Prey
One theory suggests the contrasting red tips may momentarily confuse or distract insect prey targeted by the waxwing. This could aid in successful prey capture. However, this has not been definitively proven.
Camouflage
The red tips may help camouflage waxwings in their natural habitat among ripe berry clusters, of which many are reddish hues. This could allow them to avoid detection by predators.
Attraction of Mates
Brighter red wing tips are proposed to be a way for cedar waxwings to attract mates, indicating fitness, age, and diet. Preferences have been shown in mate selection for mates with richer red wing tips.
When Do Cedar Waxwings Get the Red Wing Tips?
Cedar waxwings first get their red wing tips when their adult plumage grows in during their first molt at around 1 year old.
Prior to this, juveniles will lack the red tips. The red tips will then be renewed and brightened during subsequent annual molts as adults.
Molting
Molting refers to the cyclical shedding and replacing of feathers. For most North American birds, including cedar waxwings, a full molt occurs once a year in late summer or early fall.
During the molt, all flight feathers are replaced. This is when the new secondary flight feathers grow in with the fresh red tips.
Juvenile Plumage
Juvenile cedar waxwings under a year old have drabber plumage lacking the red wing tips. Their feathers are more brownish-gray.
The younger birds can be distinguished from adults until their first full molt results in adult plumage.
Differences Between Males and Females
There is little sexual dimorphism between male and female cedar waxwings. Both sexes develop the distinctive red secondary feather tips.
However, some subtle differences have been noted:
Redness
Male cedar waxwings tend to have slightly redder wing tips on average compared to females. However, there is overlap between sexes.
| Sex | Redness |
|---|---|
| Male | Slightly redder wing tips |
| Female | Slightly less red wing tips |
Mask Size
Male cedar waxwings typically have a slightly larger black mask that extends farther around the face.
| Sex | Face Mask |
|---|---|
| Male | Slightly larger black mask |
| Female | Slightly smaller black mask |
However, these differences are subtle and not definitive for identifying sex.
How Long Do the Red Wing Tips Last?
The red carotenoid pigments in the secondary flight feathers will fade over time. The rate of fading depends on the waxwing’s diet and how efficiently they metabolize the pigments.
Molting and Color Renewal
Cedar waxwings molt all their flight feathers annually in late summer or fall. This replaces all the flight feathers and restores the brightness of the red wing tips.
So the red color lasts for up to one year, until the next molt. It cannot be renewed except through regrowth of new feathers.
Fading Rate
Studies show the red color noticeably begins fading after around 4 months and continues fading steadily.
By 8 to 10 months, the color is greatly reduced. But there is variation between individuals.
| Time Since Molt | Redness Level |
|---|---|
| 0-4 months | Maximum brightness |
| 4-8 months | Noticeable fading |
| 8-10 months | Greatly faded |
Diet Influence
Waxwings with diets higher in carotenoid-rich berries retain the red color longer. Efficient carotenoid metabolizers also retain color longer.
So diet and metabolic factors influence fading rate between individuals.
Do the Red Wing Tips Serve a Function?
The exact purpose of the red wing tips is still debated among scientists. Here are some of the proposed functions:
Social Signals
The red may communicate dominance, fitness, or breeding status. Brighter red is proposed to be preferred for mate selection.
Flock Cohesion
The color makes the birds highly visible to each other in flight, helping maintain unity.
Prey Capture Confusion
The contrasting red next to black may momentarily distract or confuse insect prey. However, this hasn’t been proven.
Camouflage
Among berry clusters, the red provides camouflage from predators.
No Known Function
One hypothesis is the red tips don’t serve any particular function. The carotenoids may simply be deposited in the feather tips without evolutionary purpose.
More research is still needed to say conclusively if and how the red wing tips functionally benefit cedar waxwings. The vibrancy likely provides some visual signaling advantage, but the exact mechanisms are still being studied.
Uniqueness of Cedar Waxwing Red Wing Tips
While other birds like flamingos and cardinals also get red feathers from carotenoids, cedar waxwings are unique in a couple key ways:
Localization
The red pigment is localized only in the tips of secondary flight feathers, rather than throughout the feathers.
Dietary Origin
The waxwing’s red comes exclusively from berry pigments. Flamingo red comes from algae, while cardinal red comes from insects.
Variability
The amount of red varies seasonally and individually based on diet. Flamingo and cardinal red is fixed.
Sexual Monomorphism
Redness occurs in both males and females. In cardinals, only males are red.
So while other red birds exist, the cedar waxwing’s red wing tips have unique characteristics. The specificity, variability, and origin from fruit make them distinct in the avian world.
Conclusion
The red tips on cedar waxwings provide these birds with a beautiful and unique appearance. The specific reasons why they have evolved this trait are still debated, but likely involve social signaling, camouflage, and visibility.
The carotenoid pigments come from berries eaten during molting seasons and fade over the course of a year until feathers are replaced. The degree of redness provides insights into the waxwing’s diet and age.
While many mysteries remain, the red wing tips continue to fascinate both scientists and bird enthusiasts alike. The cedar waxwing’s scarlet-tipped wings make it one of the most visually striking birds found across North America.
