From 1911 to 1986 coalminers relied on canaries to warn them of dangerous gases. The birds were taken down the pits in cages and if they showed signs of distress, the men knew they must get out quickly. Canaries react to very small quantities of deadly carbon monoxide. They were made redundant when cheaper and more reliable electronic gas detectors were introduced. The miners missed the canaries, which were treated as pets
In a way, our wild birds fulfil the same function as those canaries, because their behaviour can warn us of changes in the environment. Rachel Carson wrote her book ‘The Silent Spring’, published in 1962, to warn about the damage caused by the indiscriminate use of agricultural pesticides. If all the birds were poisoned, what would that mean for us? Not just a silent spring, but serious damage to human health. Although there are much tighter controls on pesticides now, we still rely on birds to warn us of danger, though now it’s more to do with global warming and loss of habitat.