Bird

 

There are ten thousand species of birds, almost , and this makes it more rows row birds singing among vertebrate species quartets all parties . Live birds are all included under a layer of modern birds (Neornithes), and spread in different environments on Earth , from the North Pole to the South Pole . Sizes ranging from live birds as five centimeters in stilted bees , to 2.75 meters as the ostrich . Biology suggests that the old bird appeared during the Jurassic period , before 160 million years ago , scientists believe that birds survived the extinction of the Cretaceous period - triple that occurred before 65.5 million years ago.

Featuring modern birds with feathers that covers the skin , beaks and free teeth , and put the eggs of solid crust , and possession of a high metabolic rate , and possession of a heart with four chambers , and the skeleton of lightweight but strong . Live birds all have wings , the only exception to this is a bird specification Zealand lacking the ability to fly , and the wings are forelimbs of birds , and most bird species can fly , which is endemic in the islands. Birds also digestive and respiratory organs unique convenient to fly . It is also some birds, of the smartest species of animals , has seen some bird species make things and use them , and many species of social mobility cultural knowledge from generation to generation .

Many species of migrating birds annual migrations over long distances , and migrate many other species migrations shorter and irregularly . Birds are social animals , continues through visual cues and sounds through singing, and participates in some social behaviors , which include cooperation in the care of younger siblings , fishing and habitat protection from predators . The vast majority of birds marry a marriage unilaterally , ie take each bird pairs and only one , often during the mating season and one , sometimes for years , but rarely should continue throughout their lives together . There are other types marry a multiple marriages , any male marry more than one wife , and the female rarely marry more than one husband. The eggs are laid in the nest normally , and the parents are embracing , and most of the birds take care of their young after hatching eggs for a long time .

Many bird species have economic importance , some form an important source of food , through hunting or breeding . And some species are bred as pets , particularly songbirds and parrots . Among the benefits of the birds also use the faeces ( droppings ) in the fertilizer industry . Intervention birds in cultures of human beings significantly , they are involved in some religions , poems and songs. There are approximately 120-130 species of birds exposed to extinction as a result of human activities since the seventeenth century , and hundreds of others before that , in 1200 , and currently there are almost an endangered species due to human activities , there are numerous attempts to protect them