It's a Bird's World: Toxic substances

How the deaths of vultures and sparrowhawks have alerted the world to serious environmental problems. Like the canaries which were used to detect toxic gases in coal mines, birds play a vital role in alerting us to substances which can damage a healthy environment. The price they pay to alert us can be losing their lives. Presenter: Mya-Rose Craig Producer: Sarah Blunt (Photo: White-rumped vultures, slender-billed vultures and Himalayan griffons feed on a dead cattle. Credit IUCN/Sarowar Alam)