African Wildlife & Environment Issue 78

BIRDING

The Crowned Eagle in Ethiopia is certainly at very low density and restricted to protected areas. It may be obliged to utilise exotics stands, but it is unlikely to ever be capable of surviving in the complete absence of indigenous (and thus prey productive) forests. Certain southern African countries, such as Zambia, Zimbabwe and Malawi, have almost no extensive stands of native forest today, while other countries such as Namibia were never heavily forested. Like the Martial Eagle, the Crowned has throughout modern history been persecuted by farmers, who maintain that the bird is a threat to their livestock. In fact, both the Crowned and Martial Eagles only rarely attack livestock. In some cases, however, Crowned Eagles have actually been killed while attempting to hunt domestic animals. Another cause for persecution of the species is that Crowned Eagles are considered competitors in the illegal bushmeat and poaching trades. Within the forest land-locked countries of Africa, the bushmeat trade is the largest source of animal protein for humans. It is a multibillion- dollar business with some five million tons (mostly small antelopes and monkeys, the crowned eagle's staple diet) being killed each year. The effect of this unsustainable culling is to severely depress or remove the large, medium and small wildlife species of the forests. Crowned Eagles require some 430 kg of 'bush meat' a year and thus directly compete with the industry. It is estimated that 90% of the global distribution of the Crowned Eagle may be subject to habitual persecution or the birds are even killed and eaten themselves as bushmeat. On the other hand, some educated foresters and fruit-growers actually encourage protection of populations, due to the controlling effect Crowned Eagles have on populations of potentially harmful mammals. It is now listed by the IUCN as Near Threatened.

Adult Crowned eagles will only resort to hunting large birds when mammals are scarce, but in southern Africa they can be a common component of the diet. Avian prey include guineafowl, francolins, ibis, pigeons, ostrich chicks and the fledglings of herons and storks. One nest even had the remains of a Marabou Stork which is a formidable species not usually susceptible to avian predators. Hornbills may be the most widely represented bird in the diet. Domestic animals, including chickens, turkeys, cats, small to medium-sized dogs, small pigs, lambs, and goats, are taken only when wild prey is greatly depleted. Juveniles and subadults, may take unconventional prey more frequently than adults. Conservation status The Crowned Eagle is common in suitable habitat, though at the population level, the numbers have shown a decline in step with deforestation. Declines appear to be widespread and may be increasing due to the often-fast pace of forest clearing. This species’ main habitat is rich, high- canopy forest, which is a major target of timber companies, agriculturists, palm oil and biofuel plantations and miners as well as slash and burn farmers. A charcoal-based economy outdoes mineral-based economics in Democratic Republic of the Congo and Zaire, both fuel wars and make inroads deep into previously virgin forests. As two of central Africa's largest businesses, this has a devastating effect on forests and wildlife. Charcoal taken from Kenya and Ethiopia is often thought to finance Somali warlords. Tanzania, which is more heavily developed for agriculture (largely today for biofuel) than adjacent Kenya, has even more reduced forest habitat. The Crowned Eagle is far more common in protected areas and reserves than elsewhere in its range, though it is still recorded consistently outside of these areas. Biologists in Africa now suspect that the Crowned Eagle’s adaptability to small, fragmented tracts of woodland has been exaggerated in the past. Some habitat losses have been offset by the establishment of exotic tree plantations, where this species can nest, but which generally lack a sufficient prey base.

John Wesson jwesson@wessanorth.co.za

46 | African Wildlife & Environment | Issue 78 (2021)