Our planet is home to almost 10,000 species of birds in all types of habitats. Birds live in forests, deserts, mountain areas, prairies, across all the oceans and at the two Poles.
What mainly distinguishes birds from other animals is their feathers. If an animal has feathers, it’s a bird. In addition to feathers, a bird has wings that have evolved from its front legs – though not every bird uses its wings to fly. All birds also lay eggs.
Birds exhibit the most incredible diversity. They range from the tiny humming-bird weighing just 1.5g to the ostrich, which tips the scales at 150kg. Few other animal groups show the same fantastic colours as our feathered friends. In many cases, the purpose of the plumage is to attract a partner during the mating season.
Each species is unique in its appearance, in its habits and in where it chooses to live. Some live in large flocks while others are solitary. Some stay in one place while others fly to the other side of the world every year.
Status and conservation
Since the 1500s, we have lost more than 150 species of bird. Today, one in eight bird species is at risk of extinction, and some 200 are classed as Critically Endangered on the International Red List. Particularly alarming is the rapid decline among many species that were once common and widely distributed. This may be a sign of a more extensive environmental problem.