ANIMALS : birds

 The birds :

What is a bird?

    Birds are the most flighty animals that have ever existed. They form a branching class of the vertebrae and are distinguished from other members of the animal kingdom by their plumage. Their ancestors were most likely theropods, small predatory dinosaurs that lived over 150 million years ago. The scales of theropods turned into feathers, their forelimbs lengthened into wings, their distinct vertebrae tails disappeared, their mouths and teeth were replaced by a beak, a lighter organ. Evolution has made birds the masters of the sky and allowed them to colonize our entire planet.

>> some characteristics :

 ● Powerful pectoral muscles to activate the wings. 

 ● Down covering the skin.

 ● No protruding ears.

 ● Thin skinned legs.

 ● Large eyes and keen eyesight.

 ● Lightweight, toothless spout. 

 ● Compact and aerodynamic body shape.  

 ● Tertiary flight feathers ensure smooth flight. 

 ● The secondary flight feathers provide lift. 

 ● The primary flight feathers provide propulsion and maintain flight stability.

The first birds :

    The world's oldest fossil bird, archeopteryx, lived some 150 million years ago. Half-dinosaur, half-bird, he already had feathers, but had teeth, a tail with distinct vertebrae and claws on the forelimbs.

The plumage :

    Birds are the only feathered animals. Their plumage is not only used to fly, but also to conserve body heat. They are warm-blooded animals, which means that their internal temperature remains constant regardless of the ambient temperature, unlike reptiles whose temperature is variable.

A suitable beak :

    The beak appeared during evolution because it is lighter than the toothed jaws, which facilitates flight. It is also simpler: a thin bone covered with the same hard protein from which human nails are made. Evolution can therefore modify its shape easily, giving each species of bird a beak adapted to its way of life. Raptors, for example, have hooked beaks for piercing their prey.

Senses :

    In birds, sight is the most developed sense. Most are able to perceive colors invisible to the human eye or to distinguish in the distance elements so small that humans would need a telescope to see them. 

 ● While they sleep, part of their brain remains awake and alert. 

 ● In general, their sense of smell is poorly developed, but their hearing is excellent.      When a bird sings, we will perceive a single note where its congeners identify 10 different notes.

The digestive system :

    Birds are toothless so they have to grind their food after swallowing it. They therefore have a special stomach pouch, the gizzard, whose powerful muscular wall compresses and crushes food. Some birds even swallow gravel to improve the functioning of their gizzard. Many people also have a crop, a pocket in the esophagus where the food they eat stays. This crop allows them to quickly swallow their meal and regurgitate it later to feed their young or to weigh less when it is necessary to flee. a danger.

A presence in all circles :

    Apart from the deep seabed, birds have colonized all the best, from deserts to cities to distant islands, mountains and frozen expanses of Antarctica. More than any other animal, a bird is able to withstand the harshest climates and the poorest oxygen environments.

The reproduction :

    Birds are aviparies, like reptilian ancestors. But unlike most reptiles which are content to drop their eggs, birds incubate them and, after hatching, care for the young. Usually, parents cooperate in keeping, protecting and feeding their young.

Passerins :

    The order of passerines is the most common >> {of the 9700 species of birds that exist in the world, 5700 are passerines}. Most of the birds that live near our homes and in our gardens belong to this order.