(Common) Stonechat
Saxicola torquata

A bird of heathlands, they make a distinctive noise reminiscent of two pebbles being knocked together, hence the name. They often perch on gorse or shrubs to keep a watch. This is a male, denoted by the black head.
 

(Common) Stonechat  (Common) Stonechat

1-2: Yateley Common South, Hampshire, 10/04/2006.