Research Update #5

On the last day of July,  I am at the starting blocks and now quite prepared for the 2012 breeding cycle.

The first of the known nesting pairs for 2012 has just hatched two eaglets, while another six pairs have gone down on eggs in the last couple of weeks.   From Ballito on the north coast, to Umdoni on the south coast, and as far inland as Howick, there are about 30 nest sites (some of which still need to be confirmed as still or recently occupied).  Out and about I have also seen several displaying pairs, and heard of other from reliable residents, that don’t coincide with current known territories.   Finding these nest sites will require a serious investment of searching effort.

as she rolls out of another loop - the female catches the sunlight on her underwing

look closely - it is amazing how flat and concealed such a large eagle can be

Lately with a little bit of self-justified ‘extra time’ on my hands (more accurately - a misdirected procrastination from drafting my introductory chapter) I have been out and about trapping some of the fledged juveniles from the 2011 cohort.  And had success with two birds, one in industrial Pietermaritzburg, and one in a rural residential area in Hilton.  While the sexes of most raptors are dimorphic, some Crowned Eagles appear quite marginal in their size – and it remains to be seen whether there is overlap between the smallest females and the largest males.  DNA sexing tests will provide unequivocal results – though in the meantime I have laid my bets based on some biometric information, and the behavior of the individuals.

The first two seemed quite catatonic in the hands, while my guess is the most recently caught was a male and a lot more coherent while being ringed - he tried to bite even while hooded.  Indeed he succeeded at one point, and managed to give me a very painful nip’l.

the third juvenile ringed  © Niel Rasmussen 

I find this particular observation quite interesting.  I am estimating from the moult pattern that this bird is about 20-22 months - a male that has found its ‘grown-ups’ voice.  This call is often heard when adults are sky-dancing over their territories either as courtship or as a territorial display.  So what is this guy up to?