phil I have seen perhaps between 20/25 birds over the years both light and dark morph, that by no means makes me an expert far from it but the species reminded me more of a black kite than buzzard hooked carpels when gliding, graceful, wings more parallel almost raven like, its a minefield and I am sure other people will disagree with me. in the end be it light or dark morph I usually try to get the so called landing lights which are difficult from directly below or a real pointed head profile, a minefield, good luck and best wishes hope this helps
terry whalin
