دانلود کتاب State of the world’s birds: taking the pulse of the planet

State of the World’s Birds is BirdLife International’s flagship science publication, using birds to assess the condition of our ecosystems as a whole. Five years in the making, this latest analysis of the scientific literature pinpoints the major trends and changes in bird populations, exploring the causes and identifying conservation solutions.

Birds are one of the best known and most highly valued elements of the natural world, comprising more than eleven thousand different species, an extraordinary variety, ranging from hummingbirds to ostriches, from penguins to eagles. Each species is unique, in its appearance, in its habits and in where it is found. Some occur in huge numbers and others are represented by only a handful of remaining individuals; some are relatively sedentary, with individuals spending their entire lives in an area of a few hectares, while others undertake extraordinary annual migrations, covering literally half the world.