Scientists theorize that birds evolved from dinosaurs. This theory for the evolution of birds was brought about by the discovery of a fossil species possessing feathers. This fossil species called Archaeopteryx lithographica dates back to 150 million years ago and is thought to have evolved from dinosaurs called theropods. Archaeopteryx lithographica had two strong legs and walked as a bird does. Its skeleton was reptilian whilst it had the feathers of a bird. Recently, two other feathered dinosaur species were discovered in China. Scientists believe that this adds further proof to the theory of the evolution of birds from dinosaurs.
Other Scientist argue that birds evolved a long period of time before Archaeopteryx. They theorize that the evolution of birds occurred from 4 legged reptiles that died out with the dinosaurs. Such scientists believe that the actual ancestors of our birds today only appeared some 65 to 53 million years ago. This view is not popular amongst scientists though.
There are two theories as to why feathers would have developed in the evolution of birds. One is that because the ancestors of birds where becoming warm-blooded, they required the insulation of feathers. Another is that they develop due to a need for flight and gliding. Whilst many creatures have been and are able to fly, feather-powered flight is unique. This ability to fly gave birds the competitive edge as they could travel over greater distances and areas whilst seeking food. This also allowed them to live in places inaccessible to other animals.
Bird species have adapted to fit into various niches (a place and purpose in relation to the entire ecological community). They have developed instincts to feed, breed and migrate in a way that is species specific.
Birds today continue to adapt to the changing conditions of the world. Unfortunately, these changing conditions have seen many species become extinct. However, increasing awareness of the need to protect the environment and the animals who live in it may ensure that future generations will continue to enjoy these fascinating creatures.