6 Different Types of Feathers in Birds and their Functions

Birds enjoy a special status in the animal kingdom for being the only species with feathers. No other animals currently living on earth, including flying mammals like bats have feathers. But what are feathers? They are lightweight, soft materials present on the bodies of birds which are made of Keratin, the same substance present in hair, nails and scales. Feathers form the bird's identity, which lets us distinguish one species from the other.

They allow the bird to take flight and also keep them insulated from harsh weather conditions. They also play an important role during mating, when bright colored feathers attract potential mates to the birds. Feathers are also water-resistant and protect the birds from harsh sun rays.

While we definitely have heard or read about most of these benefits of feathers, not many of us know about the types of feathers. Yes! Not all birds have the same feathers as the types vary based on their size, habitat and flying conditions.

In this article, we have listed 6 Major Types of Feathers found in birds along with their functions.

6 Different Types of Feathers and their Functions:

Feathers are divided into 6 major types that differ in structure, shape, and function. Let us now understand each of these different kinds of feathers in detail:

1. Flight Feathers:

Flight feathers are long feathers which are usually present on the wings and tail of a bird. As the name suggests, these feathers help the bird in flight by generating thrust and lift. Flight feathers are quite strong and stiff to withstand the strong wings they deal with. The wing feathers are called remiges, which are asymmetric with shorter and stiff edges. The tail feathers are called rectrices which are arranged in a fan shape and offer steering control to the birds.

Remiges are again divided into three types –

Primary feathers- they are the largest feathers present on farthest from the body and essential ones for flying

Secondary feathers- they are present on the 'arms' of the wing and offer control to the bird during flight

Tertiary feathers- they are short feathers which are present in the inner wing and close to the body of the bird

2. Contour Feathers:

Contour feathers are the exterior feathers of a bird that offer shape and color. The top part is made of barbs that form a stiff vane, the flat surface of the feather. This section contrasts with a fluffy base attached close to the body. Coming to the functions of these two parts, the top section is water-proof by using oil from the uropygial gland located at the base of the feather. This part helps in streamlining the body during flight along with having attractive colors and patterns which offer social displays. The lower section aids in thermoregulation and keeps the body of the bird warm

3. Semi-plume Feathers:

Semi-Plume feathers are a cross between down and contour feathers which are quite soft to touch. They have well-formed shafts and a fuzzy-like texture due to lack of hooks in the barbules. Due to no interlocking of barbs, the vanes are quite soft and fluffy to touch. The main function of sem-plume feathers is to offer insulation to the birds. They are concealed under contour feathers to protect the body of the birds from cold winds. In species like the Egrets, semi-plume feathers also help with courtship and have a lacy look.

4. Down Feathers:

Down feathers are even softer than semi-plume feathers due to the lack of interlocking barbules of pennaceous feathers. As a result, these feathers are extremely soft and fluffy, usually found under the sturdier exterior feathers. Young birds and chicks of species like hens, ducks etc. are covered in down feathers when they hatch. There are three types of down feathers – Natal down, body down and powder down.

Natal Down are those feathers which cover the bird during the early development of the birds i.e., when they hatch or after a few days or weeks of hatching.
Body Down feathers are found on bigger birds under the outer contour feathers as a small, fluffy layer
Powder Down feathers are disintegrated particles of keratin present in the barbules of feathers which appear as dust.

5. Filoplume Feathers:

Filoplumes are the smallest of all feather types which look like small paint brushes. They have a rachis, which is the stick structure with just a few barbs on the tip. These feathers are usually hidden underneath the contour feathers on the wings. Until recently, the exact function of filoplumes remained as a mystery to scientists. Some opined that they offer insulation, while other argued that they were underdeveloped feathers. However, recent studies confirm that filoplumes are connected to nerve receptors and might help the bird assess the damages or loss to other feathers. Additionally, filoplumes help the bird navigate well by assessing information about wind, sun, air pressure etc.

6. Bristles:

Bristles are specialized types of feathers which are found on areas like the head, neck, around the mouth and even the eyelids. They have a stiff rachis and a few barbs on the base. Bristles are known to have sensory function to let the speed and direction of the bird in air. The ones that are found around the mouth also serve as 'nets' to trap the insects in air and relish them. Bristle feathers which are present on the eyelids act as eyelashes to protect the eyes from dust and insects during flight. However, not all birds have bristle feathers and those that have them may have varied functionalities.

Those are the 6 major types of feathers found in majority of birds. While writing this article, we have realized that feathers are not mere accessories to birds but in fact, are necessities for their survival. So, the next time you are tempted to pluck some off from their bodies or buy feathers from illegal sellers, please tell yourself that you are depriving a bird of its life!