For thousands of years, songbirds were regarded by mankind as messengers from the gods. Today, these creatures have woven inextricably into the fabric of our environment and are vanishing at an alarming rate. Under threat from climate change, pesticides and more, populations of hundreds of species have dipped dramatically. As scientists, activists and bird enthusiasts investigate this phenomenon, amazing secrets of the bird world come to light for the first time in the acclaimed and visually thrilling documentary The Messenger. Find out what's killing our songbirds, and what can be done about it. As in ancient times, songbirds may once again be carrying a message to humans - one that we ignore at our own peril.