The Black Eagle Project was established in 2011 in collaboration with the Animal Demography Unit at the University of Cape Town, and over the last two years the Cape Leopard Trust has been privileged to share its journey. Set up by PhD student Megan Murgatroyd, future research will continue to focus on the effects of land use on the diet and hunting habits of the Black eagle (Aquila verreauxii), with the field studies concentrated in the Cederberg Mountains and the Sandveld.
The outcomes of the project will enable a comprehensive assessment of the effects land use has had on the Black eagle and its primary prey, the rock hyrax (Procavia capensis). We look forward to following Megan's new discoveries and developments.
Distribution of the Black eagle
Black eagles occur through most parts of sub-Saharan Africa, as far north as Israel, where mountainous habitat correlate with a high density of their main prey, rock hyrax Procavia capensis. In southern Africa their most notable absence is from most of Botswana and eastern Namibia where there are no suitable mountains due to the Kalahari Desert. Perturbation of habitats through human influence has resulted in declining hyrax populations. This is considered a major contributing factor to eagle pairs being lost from former breeding areas.
Nests are normally built on rocky cliff ledges or pillars in hilly and mountainous regions. This preference means that the nesting sites themselves are naturally robust against human encroachment. Breeding activity commences in winter with nest building as early February. However, timing is highly variable according to region.
Egg laying in the Western Cape usually peaks in June. Generally two eggs, but sometime only one egg is laid. Incubation will last between 44 and 46 days. If both eggs hatch successfully 'cainism' will occur, whereby the first chick to hatch will out do its younger sibling for food and cause physical injury until death. The remaining chick will then take around 90-98 days to fledge and remain with its parents for a further 3 - 4 months. Once the young eagle is capable of feeding itself it will be forced out of the territory by its parents.
Black eagles in the Cederberg
In the Cederberg Mountains it is still a common sight to see a pair flying in a unique pendulum formation over the cliffs and territory that they defend. However, in other parts of the country their long-term survival might be threatened by radical change in land-use. In the Western Cape at present these eagles remain prevalent and breeding in the Sandveld. Yet this area is now classed as the second most highly threatened ecosystem in South Africa and at least 50% of the land has been converted for agriculture (C.A.P.E. 2008; Low 2004).