What Is A Bird ?
Anything that falls under the group of Aves is called a bird.
Characteristics Of A Bird
- is warm-blooded;
- has two feet (also known as bipedal);
- has its body wrapped up in feathers;
- has light bones that are extremely helpful for its flight;
- has two wings;
- has a beak or bill without any teeth;
- lays solid eggs;
- enjoys very high metabolism rate
Bird Facts For Kids | Facts About Birds For Kids
- When a bird is said to be diurnal, it means that bird is lively in the daylight hours. Likewise, if a bird is nocturnal, it means that bird is lively in the hours of darkness.
- There are quite a lot of birds that stay in that very region where breeding takes place while others fancy flapping over long distances to find out their favorite habitat.
- The plumage or feathers provide perfect protection for the birds in chilly weather and keep them warm even in extreme conditions. They perform the same function as fur does for mammals.
- With the size of nearly 9 feet, Ostrich is by far the biggest flightless bird in the world.
- With the size of nearly 2.4 inches, cute little hummingbird is certainly the smallest bird.
- Despite the fact that birds enjoy beautiful plumage that helps to launch them into the air, there are some birds that cannot fly. They are collectively known as flightless birds like Ostrich, Cassowary, Rhea, Kiwi bird, Penguin and also Dodo bird (which has become extinct).
- Almost 95 percent of birds’ weight is composed of muscles while 5 percent weight is present within the bones of birds.
- A bird fancies fuelling up on plant seeds, bugs, fishes and sometimes their own counterparts (some other birds).
- Those birds that are nurtured on the assumption that human beings will gobble them fall under the term “poultry”.
- Owls are the only species of birds that have their eyes pointing in the most forward direction.
Evolution Of Birds
Birds are evolved through the natural course of time from reptiles which is why they share few characteristics with them. However, reptiles lack one thing viz. plumage or feathers, a distinguishing feature of every bird which is why birds do not fall under the category of reptiles.
Body Structure Of Birds
The shapes and body structures of different species of birds vary a lot. On one hand, there is a bird with an elongated and elastic neck like ibises, cranes while on the other hand, and there are penguins, falcons that have chubby or undersized necks. Falcons and penguins are extremely good predators both in their respective domains and they stalk their prey quite efficiently primarily because of their torpedo-like body structures which diminishes friction.
Purpose And Structure Of Bills And Beaks
If you look at bills and beaks of birds, you find great variation in their shapes too because it helps them while feeding on seeds, insects and other eatables. Some birds like finches have very strong bills designed for ripping hard seeds while other like Kiwis have elongated bill used to snoop inside the soil and a magnificently crooked bill of nectar feeder and finally a rock-hard bill of vultures intended for ripping bones open. Besides, the beak (not all, but some beaks) also serves another important purpose which is to catch the attention of opposite gender by sending special gestures. As breeding season approaches, the bill of cattle egret initially of yellow color changes its shade to yellow-carroty or somewhat orange color.
Structure Of Feet
The design of legs as well as feet of different species is designed for particular purpose:
Webbed feet | allows the bird to swim
Elongated and cuddling feet | allows the bird to roost or perch on trees and so on
Horizontal and petite feet | allows the bird to sprint on land
Strong and heavy claws | allows the bird to stalk its prey (all birds of prey have these feet like eagle, owl or hawk)
Arrangement Of Legs
The legs of some birds like Jacanas are stilt-shaped and their toes look a lot like spiders as they are perfectly designed to stride on marine vegetation like lily-pads. The length of Jacanas’ feet is equal to the entire size of the bird. Likewise, on one hand you witness few birds like Emus or Ostrich carrying elongated and powerful legs that help them to gallop and some birds like to flutter into the air for the most part, have almost no legs at all (like swift birds that fall under the family of Apodidae). The swifts rely primarily on their wings rather than legs.
Arrangement Of Toes
Birds that walk on solid grounds have very small or perhaps do not have a back toe like a two-toed Ostrich. There are some other birds’ species that enjoy four toes as well however the difference lies in the way they’re put together. For instance, many bird species (like roosting species) have three or perhaps four toes and except a back toe (which is always in opposite direction as compare to the front toes), all other face in the direction of the bird’s face; few birds’ legs have two in the back and two forward and finally the four-toed swifts have the arrangement of their toes facing forward with no hind toe.
The Senses Of Birds
Structure Of Eyes And Eyesight Of Birds
Due to the active nature of birds, they need to have wonderful senses in order to dash and to escape from predators. Thus, eyesight is generally the leading sense of most of the birds. The eyes of birds are quite big and are fixed on both sides thereby enabling the bird to have a larger vision possibly 300o angle view. This broader angle of view helps the bird to avoid potential dangers. In case of raptors, the position of both eyes is slightly ahead than other birds enabling them extra view. This position of eyes is particularly good for witnessing minute details of prey. However if you compare the eyes of mammals with birds, you’ll see birds’ eye is somewhat static while mammals’ eye is movable. In order to rise above to this hurdle, birds make use of their flexible head that can move about at 270o angle. The eyes of such birds are shielded by a specially designed membrane known as nictitating membrane. These unique eyes of birds allow them to spot their prey (whether on ground or below the surface of water) very quickly while in the air. Even though you can say the sharpness of our eyesight may be moderately better than birds but the sphere under which a bird spots its prey is much greater and that too with great acuteness, ability to pick out different hues and what’s more, it can easily single out its target inside polarized as well as UV lights. The number of rods inside the retina for nocturnal birds (birds that become alive during nighttime) exceeds their cones which help them to spot their prey even when the light is weak.
Hearing Sense Of Birds
Echolocation acts like a sonar or radar and is installed inside many animals like bats or dolphins. Some birds also use echolocation like swiftlets and oilbirds. The principle behind its working is that a bird or animal generates a very sharp sound that after striking the prey comes back to the source and the animal hears it through its special receptors or ears. Birds that use echolocation (typically residing inside caves) easily stalk their victim with it. Basically these birds give off special clap-like sounds that steer them toward their prey even in nighttime.
The receptors are spread out all over the bird’s body which indicates that they have a highly-sensitive sense of feeling ache, sense of tapping and so on. But sense of smell or olfactory organs within birds is not too good and apart from Kiwi bird or vultures of New World, there is hardly any other species that prowl by means of smell.
What Is Plumage Of Birds And Its Purpose
If all the feathers of a bird are known by one word, that is ‘plumage’. Birds are the only species that have feathers on their bodies. Thus it is a hallmark that is exclusively for birds. There are numerous uses of these feathers setting aside that they are brightly hued and easy on the eyes. The fluffy feathers are really powerful and not only do they help the bird in flying (aerodynamics) but they are also extremely valuable when it comes to keeping the bird warm and cozy in chilly weather. These feathers also save the bird from elements like cormorants and for birds that plunge in water like penguins; they help them while falling (hydrodynamics). However, you’ll be surprised to know that birds like snipe generate sound with the help of these feathers and sandgrouse brings water to its fledglings through plumage.
Six Types Of Feathers
A special substance known as keratin is what makes up bird’s feathers. Generally there are six primary kinds of feathers:
- Flight feathers
- Contour feathers
- Semi-plumes feathers
- Down feathers
- Bristles feathers
- Filoplumes feathers
Physiology And Anatomy Of Birds
The magnificent blend of bodily processes of birds with fluffy feathers allows them to take flight thanks to the strong structure of bones that they possess. They have extraordinarily lightweight bones, and unlike mammals, their skeletal is hollow so in order to help them soaring high in the air. Besides, the bills of bird species also have negligible weight. Next unusual thing about the skeleton of birds is that the central part of the skull bone or other skeletal contains air and there are small channels linked with nasal cavities as well as respiratory structure through air sacs. This phenomenon is known as pneumatization and unlike diving species (that do not have such characteristic or very little because it’ll hamper their living); it is more widely present within flight birds.
The point from where the two wings and legs of a bird propagates (just round the bird’s breast), is actually the nucleus where all the strength of muscles is unified. Thus, this portion of a bird provides perfect lift while taking off. If a bird plans to steer itself in the air, the big tendons are there to take the bird to that precise direction and are present at the tip of limbs. Unlike flightless birds, others like terrestrial bird species possess huge and powerful muscle of wings and breasts since most of the strength is fused within the upper portion of their legs. Those birds that like to roost on tree branches have a tendon that surrounds the ankle in back. There is a flexor muscle actually that molds and narrows itself into a tendon. As a result, these tendons are extremely helpful for a bird as it folds over on trees. As the bird comes to rest on a branch by twisting its ankle, as a result the toes squeeze round that branch. The bird clings to the branch so tightly that if it takes a nap even then it does not lose the grip around it. Besides, there are ridges too in few bird species’ toes and which also performs the same function of tightening the grip.
Respiratory System And Body Temperature Of Birds
A diaphragm is basically a muscle that helps a great deal in respiration and it is present within all mammals including you. The volume of heart, ribs and lungs increases because of the narrowing of diaphragm and as a result, air gets into the lungs. However in case of birds, they do not have such diaphragm and so respiratory system of birds is quite different from mammals. In birds, there are air sacs alongside the lungs. They help in inhalation and controls temperature a great deal. Air sacs are spaces inside the birds that have air inside them and links bone with lungs. The respiratory systems of birds are very successful as compare to mammals since they consume almost 25 percent surplus oxygen on every inhalation. That is why some birds flutter as high as 9,000 meters even though the level of oxygen at that point is minimal. Like all mammals, birds also sustain and give off their heat thanks to the metabolic rate which is pretty high in them. Some species are able to sustain this body heat at almost 100oF or up to 42oC and thus it is more than mammals’ temperature by almost 7oF or 4oC. However in chilly conditions, it is easier said than done to sustain such warmth within the body. Therefore, few bird species cut down the temperature within them just for couple of days and turn itself into an inactive bird. This phenomenon is known as a ‘bird has developed itself into a torpid’. Having said that, there are species of birds that respond in a rather different way like they raise more thick plumage in order to survive in freezing temperatures, or they escalate their metabolic rate up to some extent or produce an extra sheet of fat or perhaps hugging in a flock of other birds or folding over the legs under their body so that warmth may not get wasted and finally by shaking their plumage to gather as much air as possible. When it comes to scorching temperatures, birds adapt themselves by puffing or shrinking down its metabolic rate or try to move under the cool shadows of trees or other things and finally by moving up their plumage, they manage to gather puff of air to release some heat from its body. This is because they do not have sweating glands that cast off the warmth from the body.
Process Of Digestion And Secretion Of Birds
Since the metabolic rate of birds is pretty high, so it’s not a big deal for them to digest food because it helps in absorbing the cuisine at a brisk pace. This is also because of the fact that birds have a unique cycle of different organs that help in processing the food and majority of birds have another muscular organ that squashes the solid food matter in order to allow gastric fluids to enter without any difficulty. That is why you may find few bird species that also gobble small rocks in their diet because it assist them squashing the food and making it easy to digest. The length of these organs that process food is not big in case of birds that go after bugs or flesh while it is quite long among typical bird species that feed on seeds or fish.
Conservation Status Of Birds
Unfortunately, humans have always been the primary cause of extinction for some birds like Dodo bird. They have destroyed birds’ habitat (deforestation) and hunted them for food or other usage. There are many species of animals that are endangered and so birds are no exception. Due to the incredible rate with which they are falling off, the Worldwatch Institute believes that by the end of one hundred years nearly 1,200 birds’ species will die. The primary causes of this possible extinction are:
- deforestation resulting in the loss of habitat;
- stalking by humans and introduction of outsider animals;
- leakages of oil;
- changes in environment or climatic conditions;
- extensive usage of pesticides.