I can’t figure out what instrument is being used to aid in keeping his beat. It sounds like pizzicato on the cello, it’s too high for a double bass I think?
It’s better to hear at 2:01 because the violin doesn’t quite drown it out as much.
Igor Stravinsky in rehearsal conducting "Scherzino".
In this 1967 program from the Canadian Broadcasting Corporation, he is seen in rehearsal and performance segments, leading The Toronto Symphony in his Suite from the ballet Pulcinella.