Another breeding season has come to an end for the Black eagles which gives me time to reflect on another season of research.
For the eagles it was certainly a tough year in the Cederberg – With only 11 pairs attempting to breed and only 6 young fledging. Must note here that since the helicopter survey there are of course many nests which are not included in these statistics. Nevertheless it certainly highlights the high rate of failure, mostly caused by adverse weather during the hatching stage.
In contrast I have had many happy adventures in the Sandveld this year and seen an incredible breeding success story there – of the 17 pairs monitored 13 fledged a young.
I’ve put together some data below, which Lucia Rodrigues and Cape Nature have also made contributions to. Overall the most surprising result for me has been the much higher successful breeding attempts in the Sandveld compared to the Cederberg. However, don’t take this on face value – the eagles occur more densely and with more inter-pair competition in the ‘berg. So perhaps if we represented the data as successful breeding per km2 we’d see a slightly different story.
Figure 1: Breeding outcome of Black eagles from 2010-2012 (n=83) based on 39 nest sites.
So as this season closes I wanted to say a big thanks for all of your support, interest and encouragement – Special thanks to Quinton & Liz (Cape Leopard Trust), Driehoek Wine, K-Way, David & Cisca (Cederberg Cellars), Kevin (Darling Brew), Les Underhill & Andrew Jenkins (ADU), Cape Nature, Dickon (Evosat), Victor (Spanish Ministry of Environment), Hank, Alan, Marcus, Anzio (Eagle Encounters), Tom & Tessy (the Vlei), Patrick, Karen & Pierre (Waganpad), Tilia & Lawrence (Donkieskraal), Louise & Gary (Leipoldtville) and everyone I’ve met on the road!
See you all next season!