Emile, that is quite existing news.
There is a breeding pair of Black Eagles which nests at the Walter Sisulu Botanical gardens (see
http://www.blackeagles.co.za/) which about 7/8 km away as the ‘eagle flies’. It could be that pair whose territory extends to Kings Kloof or in fact a different pair (which will be really good news as the number of breeding pairs in Gauteng has been declining for decades). The typical cycle for Black Eagles is to start with nest building activity in Feb / March, their chicks hatch in April and then a single juvenile is raised and after fledging stays within the territory until it is chased away by the adults around the end of the year. It will be very interesting to confirm what is actually going on and if it is a different pair / nest. One would also need to consider whether there may be any potential impact from climbing activities on the Eagles.