‘Canaries in the coalmine’: loss of birds signals changing planet

Billions of birds are disappearing because of humanity's impact on Earth, global review finds

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.