When we talk about birdsong, we cannot simply refer to a single “voice”. It is a great chorus of complex sounds, it is a real language in itself. The dry “teak” of a sparrow, the plaintive “gheck gheck gheck” of a woodpecker, the shrill “chirrip” of a lark – each sound has its own purpose and is used in very specific circumstances. For birdwatchers, learning how to ‘decode’ the secret language of birds is a great way to identify different species and to better understand their behaviour.