Look up, listen and be very concerned. Birds are vanishing – and their crisis is our crisis | Mark Cocker

More than 40m birds have disappeared from UK's skies since 1970: a trend that imperils the network that gives us life

Most mornings in spring I listen for a sequence of birdsongs to know that my local area is in good heart, but also to reassure myself that the world is working largely as it should. The default soloist of my dawn in Buxton, Derbyshire, is a mistle thrush that delivers from the ash tree above our house.

As I listen to my soloist there is an added delight in knowing that, from Cape Wrath in northernmost Scotland to Kingsdown in Kent, his voice unites with tens of millions of other dawn birds. The blue and great tits of the inner cities, blackbirds and robins among the English villages, chaffinches and wrens through the remotest Scottish glens: it is a collective performance, free of charge, unfolding across all Britain to all people.