Hello Bird Lovers!
From peacocks and parrots to finches and quails, there is an amazing amount of variation in feathers from one bird to another. Bird feathers come in every color of the rainbow, sometimes blending perfectly with their surroundings, and sometimes shining in the sunlight like an iridescent gem.
All of these feathers might look different, but all of them share some pretty important features. Underneath all of the brilliant colors, there are a few marvelous little features that come together to allow (most) birds to perform the amazing feat of flight!
Like a newly hatched baby bird, we aren’t going to start out right at flight. To start out learning all about bird feathers, I’m going to go through the seven main types of bird feathers, each of which plays an important role in the lives of our feathered friends and then will move on to flight in the final section of this article.
Bird feathers are a fascinating topic, so I’m going to dive right in with one of the littlest feathers, and ramp up to the feathers that are more import to the process of flight as we head toward the final section!
7. The Bristle Feather
Our first feather, called a bristle feather, is the simplest of all the feathers. A bristle feather consists of a single stiff rachis (the rachis is the main shaft of a feather) which doesn’t usually have many barbs or branches.
Not all birds have bristle feathers and there doesn’t seem to be a general consensus as to what exactly bristle feathers do. Most bristle feathers are found around the beak and eyes of a bird and are found on quite a few insect-eating birds like Robin’s and Flycatchers. It’s believed that the sharp stiff nature of bristle feathers helps protect a bird’s face and eyes against their wriggling insect prey.
Bristle feathers may also play a role in helping a bird sense it’s immediate surrounding, much like a cat’s whiskers. While this is probably relatively useful for most birds, it’s much more important to another bearer of the bristle feather, the Owl.
Owls have phenomenal eyesight when it comes to objects at a distance, it’s one of the things that make them such successful hunters. However, an owl’s eyesight is not nearly as good when it comes to the things that are nearest to them, which is where bristle feathers come in. Owls have quite a few sensitive bristle feathers that assist them in keeping track of their immediate surroundings, while their sharp eyes are busy looking for tiny mice rustling in the distance.
Owls actually have quite a few amazing adaptions, so much so that I’m considering writing an entire article about them. Keep an eye out for the subject in my next Twitter poll!
6. The Filoplume Feather
Much like bristle feathers, filoplume feathers are short and have very few barbs. Filoplume feathers are even thinner than bristle feathers. A filoplume feather is generally thinner and less stiff in order to allow for more movement which is important to its main function.
You see, also like a bristle feather, filoplume feathers are used to sense the position of contour feathers (don’t worry, we’ll get to contour feathers) which are found close to the body. Filoplume feathers are especially important to sense the position of contour feathers on the wings of the bird. The position of every feather on a birds wing is important in order for the bird to fly most efficiently.
Filoplume feathers can be extremely hard to see on a bird, especially in a photograph, so unfortunately for this one, I don’t have a picture example for you.
5. The Down Feather
I’m going to make a firm statement here, and if you disagree with me then, well, I hope you’ll keep reading anyway and that we can still be friends. I firmly believe that down feathers are absolutely…
…the cutest feather ever!
Who doesn’t like down feathers? They’re soft and fuzzy and adorable baby birds are covered in them!
In all seriousness though, down feathers are extremely important to birds of all ages. Down feathers generally only have a calamus (the hollow base of a feather that doesn’t have any barbs.) and a collection of soft disconnected barbs with a much looser branching formation than other feathers. Down feathers generally have little to no central rachis, which allows the barbs to move much more freely than the barbs of other feathers.
The soft, fluffy down feathers of a bird form a layer over most of their body between the skin and the top layer of contour feathers. Down feathers provide an insulating layer that traps heat against a bird’s skin and keeps them warm even at high altitudes.
4. The Semiplume Feather
Semiplume feathers are something of an intermediary feather between down feathers and contour feathers. Unlike a down feather, the Semiplume feather has a strong central rachis that creates a shape that’s more traditional feather-shape.
Apart from that central rachis, a Semiplume feather is very similar to a down feather, with soft unconnected barbs that provide a second layer of insulation between down feathers and contour feathers.
3. The Contour Feather
Although our top two feathers are generally considered the most important for flight, the contour feather is just as important!
Most of you have probably seen a naked bird at some point, whether it was a baby, a bird with a habit of plucking, or even a chicken or turkey at the store. The actual wing of a bird is very thin and sinewy, while their powerful breast muscles (built largely for flying) generally seem disproportionally large.
If a bird was had nothing but the feathers we’ve discussed so far, plus their main flight feathers, they would be unbelievably clumsy in the air, if they could even maintain flight at all! Contour feathers are arranged on a bird’s body in an overlapping pattern much like shingles on a roof. They work together to form the sleek aerodynamic form that we’re used to seeing on a bird.
Contour feathers are quite literally the bridge between the main flight feathers and the fluffier under-layer of feathers like the Semiplume and Down feathers. The ends of a contour feather hook together, much like our next two feathers, creating a sleek, waterproof surface. As the feather descends under other contour feathers toward the body, it stops hooking together smoothly and starts to form a looser, fluffier pattern similar to a Semiplume feather.
We’ll discuss this a little more in the Flight section, but without the addition of contour feathers, a bird would be about as aerodynamic as rubber chicken!
2. The Tail Feather
Welcome to the top two feathers! These feathers are the biggest, strongest, and generally the most important when it comes to flight.
Of the long tail and wing feathers, tail feathers tend to have a straighter rachis. The firm, straight line that the rachis of a tail feather makes creates a strong fan-like rudder that allows for precision steering when a bird is airborne. Tail feathers are just as important to steady flight as wing feathers are, and they are both classified as flight feathers.
One of my favorite features of tail feathers is the positioning of the rachis on the feather in relation to the position of the feather on the bird’s tail. Birds have, on average, six pairs of feathers in their tail, the central-most feathers have a rachis directly in the center of the feather. Some of the most symmetrical bird feathers you’ll ever see come from the center tail feathers!
As you move toward the outer edge of a bird’s tail, the rachis shifts toward the outer edge of the feather. This anatomical arrangement lets the bird make tiny shifts in each of the feathers of its tail. The arrangement of these tail feathers is one of the reasons birds can perform such incredibly precise feats of aerial acrobatics!
1. The Wing Feather
Wing feathers could probably be described as the rock stars of the feather world. I think almost everyone who loves birds has had a moment in their life when they looked in awe at a bird’s wings highlighted against the sky.
You’ll find depictions of wing feathers in art, décor, jewelry, and even tattoos! The wing feather has become a symbol of our fascination with a bird’s natural ability to fly, and I think it really deserves all the love it gets.
Wing feathers are some of the most distinctive and useful feathers on a bird. The longest of the wing feathers are called primary feathers, they occupy the outer half of a birds wing. These are the feathers that you can see the sun through when you look up at a bird in the sky!
Primary feathers are attached to the bone, unlike most other feathers that are attached only to the skin. Strong ligaments attach primary feathers to the bone which allow each feather to be moved and rotated like a finger without any joints. This allows the bird to make tiny adjustments as it flies to account for shifts in air flow and even temperature! The only other feathers that are attached to the bone on a bird are the two innermost feathers of the tail.
Secondary feathers on the wing are attached only to skin and can’t be manipulated quite as delicately, but they are just as important. Secondaries overlap each other very tightly, making the wing into a streamlined surface and creates lift under the bird’s wing.
Wing feathers have a smooth, windproof surface made possible by the interconnected barbs of the feather. They also tend to have a much more curved shape than tail feathers in order to create a sleek shape for flying. The rachis of a wing feather is placed much more dramatically to one side of the feather, creating one distinctively thicker side of barbs, one side that’s much more narrow.
These feathers are positioned on the wing so that the narrower side of the feather is facing forward, in the direction the bird is flying. It’s important that the leading edge of the feather is narrower and less flexible, to prevent the feather from twisting or bending while a bird is flying.
Now that we know some of the types of feathers on a bird, we’re going to dive into a little more about the structures that make flight possible! Our top three feathers all have one very important feature in common that allows the feather to be a sleek windproof surface.
Wing feathers, tail feathers, and the top half of contour feathers all have small, microscopic hooks placed along their length and when these hooks are aligned properly, they latch together like Velcro. These barbs, that hook together so smoothly, create the smooth wind-resistant shape of flight feathers.
Of course, these barbs don’t stay hooked together all on their own, birds go to a lot of trouble to keep their feathers flight ready at all times. If you’ve ever seen a fallen bird feather, you may have noticed that many of the barbs have come apart, giving the feather a much scruffier look than the ones you see still attached to birds.
This is because birds spend a great deal of their time preening to keep all of their feathers smooth and clean. Preening is a fascinating topic on its own, so if you’d like to learn more about it (and another type of feather) head over to this article right here.
The mechanics of how a bird flies is a pretty intensive subject that deals with bones, anatomy, and aerodynamics. Maybe we can dig deeper into the mechanics of flight itself at a later date, but this article is getting pretty long, so, for now, we’ll just focus on how the feathers themselves aid in flight.
Those primary flight feathers might be the rock stars of the feather world, but secondary and contour feathers are the roadies, making sure the show goes on and no-one crashes off the stage! Secondaries and contour feathers overlap each other very tightly and fill out the shape of the wing so that it forms an efficient airfoil. An airfoil is a particular shape that allows air or liquid to move around it in a way that creates lift. You can find an airfoil style shape in many places, including birds and planes, but also in the shape of a sailboat sail or dolphin flipper.
Airfoils come in a diverse number of shapes, even among the subset of bird wings. Bird wings and the feathers that fill them out can vary wildly in shape between species. Some birds, primarily predatory ones, have wings adapted for high-speed flight and quick accurate turns. Other birds have broader wings that are more suited to long, soaring flights. Some bird wings are even vestigial and don’t allow them to fly at all.
All of these different types of feathers and their structure works together to create the marvelous phenomena of flight. I hope that learning a little more about how feather work will allow you to look at the easy flight of your neighborhood birds with a whole new level of appreciation!
If you’re interested in learning even more about bird feathers, than I suggest this article right here by The Cornell Lab. They have way more resources than me (Like microscopes!) so their article on feathers is pretty definitive.
What’s your favorite thing about bird feathers? Be sure to let me know in the comments!