Initial deadline for comments: 31 January 2012.
Crowned Hawk-eagle Stephanoaetus coronatus is a widespread resident of sub-Saharan Africa, where it inhabits forest, woodland, savanna and shrubland, as well as some modified habitats such as plantations and secondary growth (Ferguson-Lees and Christie 2001), and can persist in small forest fragments (Dowsett-Lemaire and Dowsett 2006). It is currently listed as being of Least Concern on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN criteria.
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criteria (B and D2: Extent of Occurrence estimated at less than 20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline was not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (A: at least a 30% decline over ten years or three generations, whichever is longer). The population size may be small, but it is not believed to approach the thresholds for Vulnerable under the population size criteria (C and D1: fewer than 10,000 mature individuals with a continuing decline estimated to be at least10% over ten years or three generations, or with a specified population structure).
Concerns have been raised over the conservation status of this species (e.g. Thomsett 2011). Although the species is welcomed by foresters in some areas, it is subjected to a number of significant threats throughout much of its range, including deforestation (carried out for timber extraction, charcoal production, the encroachment of agriculture and plantations, shifting cultivation and mining), competition from humans for prey species (with apparently unsustainable levels of exploitation for bushmeat in some areas), direct persecution in an estimated 90% of its range (e.g. for food, arrow-fletching, witchcraft, ornaments and its pest status and threat to humans) and human disturbance (Ferguson-Lees and Christie 2001, Hockey et al. 2005, Thomsett 2011). This suite of threats implies that the species could be in rapid or fairly rapid decline, especially considering its slow reproductive rate (Thomsett 2011).
In reviewing the literature, Ferguson-Lees and Christie (2001) state that the species is now rare in many parts of West Africa, implying that it has declined in that region. Its range in Malawi is said to be certainly decreasing and habitat clearance there is expected to be impacting the species (Dowsett-Lemaire and Dowsett 2006). It has also declined in southern Mozambique owing to forest destruction along the coast (Parker 1999). The negative effects of habitat loss in South Africa are regarded as being partly offset by the establishment of exotic plantations (Hockey et al. 2005 and references therein).
Ferguson-Lees and Christie (2001) estimate that total the population could number in the upper thousands, although given its range this is perhaps likely to be an underestimate and they also state that, for this reason, an estimate of tens of thousands might be expected. There is thus a strong likelihood that the species’s population approaches as few as 10,000 mature individuals and may even number fewer than 10,000.
Further informative data and observations are requested from all parts of the species’s range in order to aid a review of its threat status. Useful information would comprise indications of changing abundance, habitat trends and the severity of threats, whether local, national or regional in coverage.
If evidence leads to the suspicion that a decline of 20-29% has occurred over the past 56 years (estimate of three generations, based on a generation length of c.18.5 years; BirdLife International unpubl. data) and/or may be projected over the next 56 years, the species may qualify as Near Threatened under criterion A. The species could qualify as Vulnerable under criterion A if it were suspected to have declined by 30-49% over the past 56 years, and/or projected to decline at this rate over the next 56 years. The species could qualify as Endangered if the rate of decline were suspected to be 50% or more over 56 years.
Further information is also sought on the species’s total population size and the likely sub-population structure, i.e. whether all mature individuals probably form one sub-population or, if not, the likely number of mature individuals in the largest sub-population. In terms of the Red List criteria, sub-populations are defined as geographically or otherwise distinct groups between which there is little or no demographic or genetic exchange, i.e. one successful migrant per year or less.
Dowsett-Lemaire, F. and Dowsett, R. J. (2006) The Birds of Malawi: An atlas and handbook. Liège, Belgium: Tauraco Press and Aves a.s.b.l.
Ferguson-Lees, J. and Christie, D. A. (2001) Raptors of the world. London, UK: Christopher Helm.
Hockey, P. A. R., Dean, W. R. J. and Ryan, P. G. (2005) Roberts birds of southern Africa. 7th edition. Cape Town, South Africa: Trustees of the John Voelcker Bird Book Fund.
Parker, V. (1999) The Atlas of the Birds of Sul do Save, Southern Mozambique. Cape Town and Johannesburg, South Africa: Avian Demography Unit and Endangered Wildlife Trust.
Thomsett, S. (2011) Simon Thomsett on the African Crowned Eagle. African Raptors: http://www.africanraptors.org/simon-thomsett-on-the-african-crowned-eagle-part-1/