Have you ever wondered why do hummingbird’s feathers shimmer? I have wondered this myself and made it my mission to research this topic to get the answer.
A Hummingbird’s feathers are iridescent and reflect light due to the structural make up of the feather. Their feathers contain structures shaped like pancakes, called melanosomes. Melanosomes contain many tiny bubbles. These bubbles create a variety of colors with a shimmering effect.
In this article, I will share with you:
- More details about a Hummingbird’s pancake shape feathers
- Evolution and coloring
- Composition of feathers (what they’re made of)
- More Hummingbird fun facts
So let’s get right to it…
Melanosomes Shaped Like Pancakes In Feathers
Hummingbirds have a wonderful range of iridescent colors that truly catch the eye. There are over 300 species of hummingbirds that exhibit this characteristic, due to their melanosome structured feathers.
A study of 34 hummingbird species posted by Wiley Online Library identified that the combination of the air pockets and stacking of the melanosomes helps to create the coloring and shimmering effect for these birds.
We found that, in general, the melanosome stacks function as multilayer reflectors, with platelet thickness and air space size explaining variation in hue (color) and saturation (color purity).Wiley Online Library
In essence, these pancake-shaped structures in the feathers and the corresponding air pockets are what help to define a hummingbird’s coloring. Their layering help to create a more complex set of surfaces. This reflects light in an iridescent manner when the light flashes off their feathers.
It’s not just the pancake shape and the stacking, it is also the air pockets that help to create the iridescence. Below is a chart that shows the differences between the melanosome structures for several bird species.
|Solid, Cylindrical Melanosomes||Flat, Solid Melanosomes||Flat, Hollow Melanosomes|
The structure of other bird’s feathers is not as complex as that of a hummingbird. For example, ducks have shiny feathers too, but not quite the same as compared to a hummingbird’s feathers. Duck’s melanosomes are log-shaped with not as many air pockets. The changes in structure and stacking with smaller amounts of air pockets are what differentiate the glimmer in a duck’s feathers when compared to a hummingbird’s iridescent coloring.
This could also be illustrated through the use of soap bubbles. Consider a small number of soap bubbles. In this instance, you will see that it is just clear and colorless.
However, when looking at a mound of soap bubbles, stacked upon themselves in thin layers, you’ll notice shimmering colors that you would normally see on the rainbow. This is similar to the structure of a hummingbird’s feathers.
Do All Hummingbirds Shimmer?
Chad Eliason, an evolutionary biologist at the Field Museum of Natural History in Chicago who studies hummingbirds, created a team of scientists to test this theory out. They examined 34 barbules from different species of hummingbirds under a transmission electron microscope.
They found that all the structures of the feathers were the same, pancake-shaped, filled with tiny air pockets that create surfaces for the light to bounce off of.
Amongst the different species of hummingbirds, traits like the thickness of the melanosomes, how many of them were stacked on top of each other, and the size of the air bubbles varied. They said that in some of them you might have 15 layers of these air-filled pancakes creating a variety of colors.
Colors and Evolution
Eliason and his colleagues also examined how hummingbird color traits evolved over time. They consulted an existing database that describes how the different species relate to each other and how far back they share a common ancestor.
They discovered that in hummingbird barbules, the keratin outer layer has evolved independently from the melanosomes under them. This is not the case for other iridescent birds. Their structures have evolved in tandem.
This finding suggests that hummingbirds have had more freedom in the way they finetune color combinations and traits. This also explains the wide range of colors that hummingbirds have.
The next step in their research is the investigation of what happens when different species of hummingbirds breed with one another.
An example given by Eliason is two pink-throated species mate and have offspring with bright yellow colors. They are studying what different color traits are allowing hybrids to look so different compared to their parietal species.
What Are Bird Feathers Made Of?
All bird feathers are made of keratin. This is the same material that makes up our hair and nails. In birds, they are structured like small trees that resemble a trunk, branches, and leaves, The leaves are called feather barbules and are made up of cells that we now know as melanosomes.
Melanosomes are also found in our human bodies. They create dark pigments that give our hair and our skin the colors that they have.
The way that these melanosomes are structured influences how light can bounce off them producing bright colors. This is the case for most birds and hummingbirds in this matter.
Pigments are not the only thing that creates color for many of our feathered friends. How their feathers are structured also contributes to the wonderful colors that we see.
Iridescent feathers are caused by the microscopic structures that make up the feather barbules of a bird. For hummingbirds, it is pancake-shaped. For mallards, it is tube or log-shaped. The colors that we see on these birds are a result of reflected light caused by the way their feathers are structured.
As the viewing angle changes, the refracted light becomes a glowing visible color on our feathered friends.
On the other hand, non-iridescent feathers are created by the way the light is scatted by the structure of the barbs of feathers. Blue feathers are almost always created this way. Blue Jays are birds that have non-iridescent feathers. When light is refracted on their feather’s structure it turns blue. If you take away the light you will see that the feather is really brown.
Many birds have feather structures that reflect light in the ultraviolet range. This is because a wide variety of birds can draw the distinction between more colors than we humans can see. That includes ultraviolet wavelengths.
Hummingbird Fun Facts
- Hummingbirds have 1,000 to 1,500 feathers, they have the fewest number of feathers of any bird species in the world. They don’t need a lot of feathers because of their small size. This also helps with being as lightweight as possible when flying.
- There are over 325 unique hummingbird species around the world. There are only 8 species that regularly breed in the United States, however up to two dozen species may visit the country. Hummingbirds are primarily tropical species and do not normally migrate. They are mostly found in Central and South America also throughout the Caribbean.
- An average ruby-throated hummingbird weighs only 3 grams. That means to reach 1 pound, you would need more than 150 hummingbirds.
- The average lifespan of a wild hummingbird is 3 to 12 years. However, that still depends on many different factors such as the species, habitat, predators, and other threats to hummingbirds.
- If you are a birder, you know that a hummingbird is one of the most aggressive bird species despite its size. You might have one bird guarding a hummingbird feeder in your backyard. They will also often attack jays, hawks, and crows that trespass in their territory.