The world’s birds, described as the planet’s “canaries in the coalmine”, are disappearing in large numbers as the colossal impact of humanity on the Earth grows, a global review has found.
There are about 11,000 species of bird spanning the globe, but the populations of half of them are falling, while just 6% are increasing. Their flight and song make them easier to study than many animals, meaning they are the best studied large group.
