Whistling kite courtship 1

I went out to my site this morning because it was blue and cloudless. I saw a wonderful thing - a courtship flight of whistling kites. They fly close together and then one flies at the other so they look like they are crashing. Interestingly, the Reader's Digest Complete book of Australian birds says "Courting birds soar about the nest tree without spectacular aerial manoeuvres but call much, both from high exposed perches or in flight." I don't know where the nest tree is but the aerial manoeuvres looked spectacular to me. Also, I have never heard the voice of any BOP I have watched