1: Man, what an avant-garde US artist! (3)
2: Sitting in tree, sparrow's beginning song (5)
3: State control for Romanians (3,6)
4: Scale Ten after taxes (3)
5: Belonging to you, is getting to me, Herb (5)
8: A group performing with energy 'The Untouchables' e.g. (5)
9: I tear to pieces in a fury (5)
11: Drongo lacks even a pet (3)
13: Going after the final piece of puzzle for a very long time (3)