Feathers are not only a decoration for birds. They give warmth, the ability to fly, find a couple during the mating season, hatch offspring and hide from predators. Consider the types of feathers and their structure.
Why do birds need feathers?
Plumage is a characteristic inherent only in the class of birds. It is vital for birds and performs many functions. It is feathers that allow birds to fly, creating a streamlined body shape, and most importantly - the bearing surface of the wing and tail. The pen protects the body of the animal from damage and injury. Effective waterproof function - the tops of the feathers fit snugly against each other and prevent getting wet. The lower part of the contour feathers, down feathers and down are closely intertwined, forming a kind of air cushion near the surface of the skin, protecting the bird's body from hypothermia.
The plumage has a different color and shape and carries information not only about the species, but often about the gender of the bird. Appearance plays a large role in both intraspecific and interspecific communication.
The general structure of the pen
The plumage performs many functions, and each individual element may differ in appearance. Further we will consider what feathers of birds are. The structure and composition of plumage have much in common, regardless of purpose. The feather consists of keratin protein. From the same material as our nails and hair.
The structure of the bird's feather is as follows: rod, ochin, barbs, barbs, hooks. The basis of each feather is the central core. It ends with a hollow skin, which is fastened in a feather bag located in the skin. This name appeared at a time when goose feathers were used for writing. Their ends were repaired, that is, sharpened.
The upper part of the feather, on which the barbs are located, is called the trunk. Elastic filiform formations - first-order barbs are attached to the trunk at an angle of 45 °. They have even thinner and smaller threads - barbs (they are also called second-order barbs).
Hooks are located on the barbs, with the help of which the barbs are fastened together and form an elastic and dense fan, which is able to resist air pressure during flight. If the hooks are uncoupled, then the bird corrects them with a beak. The mechanism is often compared to a zipper. The barbs in the lower part of the fan have no hooks and make up its downy part.
Types of feathers
According to the structure and functions, feathers can be divided into several types:
- contouring;
- steering;
- fly;
- downy;
- fluff.
Despite the fact that outwardly the feathers seem quite simple, in structure they are complex and ordered structures and consist of many tiny elements. The structure of the pen depends on the functions performed.
Contour feathers
Contour feathers are so named because they form the contour of the bird's body and give it a streamlined shape. They are the main type of plumage and cover the entire body. The structure of the contour feather of a bird is as follows: the core is rigid, the barbs are elastic and interlocked. These feathers are not evenly distributed on the body, but tiled, which allows you to cover a large surface of the body. They are attached in pterillia, special areas of the skin. The structure of the contour feather of a bird forms a dense fan that almost does not allow air to pass through.
Steering and fly feathers
The tail feathers are on the tail of the bird. They are long and durable, attached to the coccygeal bone and help change the direction of flight.
Feathers are durable, they form a plane of the wing and are designed to ensure flight. They are located along the edge of the wing and provide the bird with the necessary lifting force and traction. The lower part of the bird's wing is covered by one of the varieties of contour feathers - covering.
Feathers and down
Feathers are located at the surface of the body, under the contour. The structure of the feather of a bird has its own characteristics: the stem is very thin, there are no hooks on the barbs. These feathers are soft, airy. They are located between the down and contour feathers. The structure of down feathers of birds allows for thermal insulation.
Fluff resembles a feather, but with a very shortened stem. Barbs also have no hooks, soft and a bunch of depart from the back.
Other types of feathers
The structure of feathers can be very interesting. There are many birds, or rather their species, and they can have their own characteristics. For example, some species have threadlike feathers. They are very thin formations with a long shaft and only a few beards at the very end. Scientists still do not know exactly what their function is. Presumably filiform feathers belong to the sensory organs and help establish the position of the flyworms.
The structure of feathers (birds of certain species) related to the sensory organs is always specific. For example, bristles that perform both sensitive and protective functions have a soft rod and several barbs at the base. They are located on the head.
There are also decorative feathers - modified contour. They have a variety of shapes and colors and serve to attract females. An example is the rich peacock tail.
Most species of birds have a special gland that produces secretions, with which animals grease their feathers. This protects them from getting wet, makes them more elastic. But there are birds that do not have such a gland, and its function is performed by powder feathers. In this case, the structure of the bird's feather is simple - it consists of one trunk, which breaks and crumbles into tiny particles as it grows, forming a kind of powder that protects the plumage from getting wet and sticking together.
Feather growth
The structure of a bird's feather can be very complex, and it is also not easy to develop. Like hair, feathers grow from the follicle. Each new feather at the beginning of development has an artery and vein in the rod, which nourish its growth. The trunk of a developing feather in the back is dark, it is called blood. After the growth is complete, the ochin becomes transparent, blood no longer flows.
The nascent feather is protected by a wax keratin sheath. At a certain stage of development, the cover is removed by the bird during feather cleaning. One, two, less than three times a year the bird completely changes its plumage. Old feathers themselves fall out, new ones take their place. This process is called molting. Most birds molt gradually, without losing their ability to fly. However, there are species that lose all fly feathers and cannot fly. For example ducks, swans.
Coloring
The structure of the feather of a bird also affects its color. Factors affecting the color of the pen can be divided into two groups: physical and chemical. Chemical factors include the presence of various pigments in the feathers. Linochromes in various concentrations provide yellow, light green and red, melanins - brown and black.
Physical factors include refraction of light in pen cells and the angle of incidence of rays. This produces a green, blue, purple hue and metallic luster.