When I arrived at the nest tree, the female was in the hollow looking out, the young one was begging, and dad was surveying the surrounds. Then came the raucous SCCs, and I saw the most remarkable sight - the male YTB eyed them from the top of the tree, angled himself, then flew, silently, straight at the very squawky SCCs . The photos tell the rest - but I was pleased to see he was successful in shooing them away.