Birds

Birds are vertebrate animals with warm-blood that can walk, fly, swim, jump to get from one place to another, some of them can stay on only one of their extremities.

They have officially four extremities, the lower are its legs and the above are the wings that unfold to fly or maintain the balance, since not all of them fly, because some have such large bodies that cannot hold their own weight during flight. 

One of the main features of birds is a body covered with feathers, which provide different types of protection, as for those who swim allows you to stay afloat and serves as thermal protection and for those who fly, it allows them to more accurately aerodynamic.

Another hallmark is their singing; they give it to the world when they have a little bit of emotion to share. Some sing to attract to females and others only seek to provide a natural serenade anywhere they go, although it is worth mentioning that not all sing.

They have a toothless curved beak and as nature wanted something original with its creation, birds reproduce by eggs incubated until hatching, so nests are the best places to take care of their babies before and after birth.

There are more or less 8600 species distributed throughout the world, but the number depends on the different taxonomic criteria. The birds live and have their chicks in the vast majority of areas around the planet, including water, land or the cup of the trees. They can live even found in the Antarctic territory, although the vast majority living in tropical areas. After all, who does not likes a warm weather?.

Some of them hate so much cold that undertake trips for several months so that their offspring born in most benign climates that those who have in their summer locations.

 For example the booted Hawk starts its flight during the month of August in Spain and ends in March in Algeria and Morocco.

Some organizations as SEO/Bird Life monitor the flight of different birds to know their migratory habits and understand its behavior. For example, they have learned that before migrating birds increase their reserves of body fat and reduce the size of some of their organs, in order to prepare for the long hours of flight.

Some territories traditionally occupied by wildlife, have been occupied by humans, which has made birds to adapt to human environments and for this reason some have come to change their eating habits, although it is not surprising if they are threatened to attacking humans to save their chicks or eggs, so sometimes, so it must be remembered that there are moments that bother them could be lethal.

Their development and competencies that have been developed to preserve their species depends on whether they are hunting birds or are hunted, for example birds of prey have a great visual acuity, while others protect depending on the capacity of camouflage  in the enviroment. 

Aquatic birds have special flexible lenses in their eyes, that allows them  positioning of images in air and in water, while nocturnal birds have a poor vision but the extraordinary ability to rotate the head sometimes up to 250°.

The smallest bird is the Hummingbird zunzuncito which has only 64 mm in length and weighs only 2.8 grams. When you open its wings it does not measure more than a few 78 mm. But the largest bird known so far is the ostrich; they can reach a measure up to 2.74 meters high and can weigh up to 155 pounds. Of course, their eggs are huge with an average of 14 cm and 1.4 kilos of weight. 

Some bird species have been domesticated as the parakeets and some singer species, others serve as human food, so bred them specifically to have a good taste, in that situation are chickens and turkeys. 

Some places have begun to raise ostriches for human consumption. Other species are admired and protected as some species of Eagles or Hawks, but all have something in common: a unique beauty.