Known as the Hedge Sparrow when I was a lad... the Dunnock is a garden favourite of mine.
Dunnock (Prunella modularis).
Dunnocks are actually song birds... the males sing in winter but most song is heard between January and July.
Ground feeders they creep around mouse-like but do visit my raised feeders from time to time.
The cuckoo will lay it's own eggs in the dunnocks nest and the unsuspecting new "parents" end up rearing a cuckoo rather than their own young.