This video is about a singing blackcap.
From Wildlife Extra:
‘Angry birds’ spotted in gardens
Feisty winter visitors arriving in greater numbers than ever before
January 2013. Thousands of Blackcaps, migrant warblers from central Europe, are ruffling feathers in British and Irish gardens. Latest sightings gathered through the British Trust for Ornithology (BTO) Garden Blackcap Survey are exploring the behaviour of these increasingly spotted ‘angry birds'.