BBC security correspondent Frank Gardner, himself a keen bird watcher, examines the sometimes surprising links between soldiers and birds and the comfort soldiers find in such an interest in times of extreme stress. It is a relationship that can be traced from those who served in the First World War trenches to troops currently serving in Iraq and Afghanistan. Featuring interviews with current servicemen and women as well as letters from the front, poetry, music and birdsong. A Ladbroke production for BBC Radio 4.