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The regional population of Kori Bustard Ardeotis kori is suspected to be undergoing a decline over three generations (47 years) approaching the 30% threshold required to list the species in the regionally Vulnerable category. It is not believed that this threshold is met and the species is listed as regionally Near Threatened pending more conclusive evidence.
The Kori Bustard occurs in two distinct populations in southern and East Africa, separated by the broad-leaved miombo woodland belt of Central Africa (Allan 1997). The strongholds of the southern African subspecies, A. k. kori, are in Botswana and Namibia, with populations also occurring in southern Angola, Zambia and Zimbabwe (Johnsgard 1991). The species is a vagrant to Lesotho and Parker (1999) reported the bird as being scarce in southern Mozambique.
Within the region, the Kori Bustard is found predominantly in the dry savannahs of Eastern Cape, Free State, North West and Northern Cape provinces, penetrating eastwards into moist and semi-arid woodlands along the Limpopo River Valley and into the Kruger National Park of Limpopo and Mpumalanga provinces (Allan and Osborne 2005). It probably formerly occurred throughout the Savannah Biome in the former Transvaal, where its present range is only a fragment of its former distribution (Tarboton et al. 1987). Historically, it occurred in the lowland areas of Swaziland where hunting, and possibly bush encroachment, has resulted in local extinction (Parker 1994).
The species occurs in 15 IBAs in the region although the majority of the population occurs outside of these protected areas. Differences in global EoO estimates (based on Minimum Convex Polygons) by Senyatso et al. (2013) indicate an 8% decline in southern Africa when comparing pre- and post-1970s distribution; the majority of the range contraction within the region occurred in Swaziland and Eastern Cape province in south-east South Africa (Senyatso et al. 2013). The EoO difference between SABAP1 and SABAP2 shows little change (c. 4%) while the AoO between the two reporting periods has declined by 55% although this may be due to a lack of survey effort in remote parts of Northern Cape and North West provinces.
The global population size has not been quantified (BirdLife International 2014). An estimate of 143-191 breeding pairs and 368-613 individual birds occurring across 18 IBAs was provided by Barnes (1998) with the largest concentrations in Kruger National Park and Kgalagadi Transfrontier Park (Barnes 1998). Anderson (2000) provided a regional estimate of between 2 000-5 000 mature individuals, although no justification for this figure is provided. The confidence in this regional population estimate is low.
The global population trend is thought to be decreasing but the rate of decline is unknown (Lichtenberg and Hallager 2008, BirdLife International 2014). Kori Bustard numbers in the region declined throughout the 20th century but the extent of decline is unknown (Brooke 1984, Dale 1990). The large decline in AoO between the two atlas periods is a cause for concern although this may be attributed to a lack of survey effort in parts of its range. Based mostly upon anecdotal evidence, the regional population is perceived to be in a state of decline but the rate at which it is declining is unknown. Exacerbating this perceived regional decline is a low reproductive rate, making recovery from such declines difficult (Dale 1990). Indeed, while the evidence for a decline is relatively strong (Senyatso et al. 2013), unfortunately knowledge regarding the rate of decline is lacking and consequently the confidence in this trend estimate is low.
The species is faced by multiple threats although habitat destruction would seem to be the highest concern (Anderson 2000). Changes in land-use and habitat quality, e.g. through establishment of agricultural fields, overgrazing or bush encroachment, may lead to diminished food supplies, causing local extinction events (Allan 1997, Anderson 2000, Young et al. 2003), although the species is occasionally recorded in transformed habitats such as airstrips, fire-breaks, pastures, field and burnt areas. Collisions with overhead power-lines may be an underestimated threat (Martin and Shaw 2010), e.g. 22 birds were killed in five months along 10 kilometres of lines in the Karoo (van Rooyen 2000). The infestation of dry, tree-lined watercourses, a habitat frequented by bustards in the arid western regions, by alien invasive plants such as Prosopsis spp. has probably resulted in once suitable habitat type becoming unsuitable (Anderson 2000). Other threats include poisoning, hunting for meat, trapping, stray dogs, droughts, human disturbance (especially during the sensitive nesting cycle) and, in the case of East African populations, wars and conflicts (Hallager and Boylan 2004). Birds are also known to be killed by entanglement in fences (DG Allan unpubl. data). The potential effects of climate change have not been fully investigated, but initial work indicates that clutches are fewer and smaller in dry years (Osborne 1998).
Gizzard content analysis has shown that birds may ingest artificial materials, e.g. bullet shells, metal, broken glass and plastic (RA Adam unpubl. data; TO Osborne and L Osborne unpubl. data), while in captivity the species has a tendency to swallow coins, batteries, nails and other artificial materials thrown into enclosures (Bailey and Hallager 2003); whether this has any adverse health effects is unknown, but it is probably a minor threat. Little is known about natural health and disease issues affecting the species, but captive birds have succumbed to a variety of diseases including Newcastle disease, avian pox and West Nile virus (Hallager 2010, Loomis 2013). Natural predators include Lion Panthera leo, Leopard P. pardus, Cheetah Acinonyx jubatus, Caracal Caracal caracal, and large raptors such as Tawny Eagle Aquila rapax, Verreaux's Eagle A. verreauxii and Martial Eagle Polemaetus bellicosus, and African Rock Python Python sebae (Hallager and Boylan 2004).
The species is listed under Appendix II of CITES and is listed under Schedule 2: Specially Protected Wild Animals under the Limpopo Environmental Management Act No. 7 of 2003. Following a strategic workshop in 2009, the Bustard Working Group was established with the support of BirdLife South Africa, to assess the growing cause for concern over the conservation of South Africa's ten bustard and korhaan species. Valuable population data is generated through biannual censuses conducted via the Coordinated Avifaunal Roadcount Project. Given the increasing concern for survival of wild populations, captive breeding programmes are underway, notably in the USA, under the management of the Kori Bustard Species Survival Plan (SSP), a programme of the Association of Zoos and Aquariums (AZA). The Kori Bustard SSP has also produced an International Studbook for the Kori Bustard (Hallager 2010), which preserves detailed records on the numbers and demography of birds in captivity including current and historical population statistics, origins of captive birds, institutions holdings birds, captive reproductive parameters, fecundity and mortality statistics, age structures and health issues. Two institutions in South Africa currently have captive birds: one pair in Umgeni River Bird Park, and one pair in the Johannesburg Zoological Gardens. The AZA's Kori Bustard SSP has also produced a Husbandry Manual (Hallager and Boylan 2004), which includes practical advice on management in captivity to zookeepers e.g. capture, handling and transport, enclosure specifications, recommended diet, population management and social organisation, health, veterinary care and reproduction and development. The SSP also produces an annual newsletter, The Gompou, which features updates on the aforementioned topics (available online through the Avian Scientific Advisory Group website, at www.aviansag.org).
Pending outcomes of research into the severity and extent of the multiple threats faced by this species, conservations efforts should probably be focused mainly on commercial farmland, rangelands and game ranches outside of formally protected areas, where Kori Bustards appear to have declined (Senyatso 2010). Education of the public and collaboration with private land-owners are key to establish and maintain beneficial land-management practices and eliminate hunting, persecution and disturbance. Given the great amount of research into husbandry practices and the well-established captive breeding programme in the United States of America, South African conservation agencies should investigate the possibility of starting a captive breeding programme locally, under the guidance of the Kori Bustard SSP, with the aim of re-introducing birds into suitable habitats within their former range.
* Research into the demography, population structure and mortality/fecundity rates of the species will help to develop statistical models to address questions related to local population health, minimum viable population and conservation area sizes.
* Ecological studies to determine how Kori Bustard abundance and population size relate to factors such as protected area designation and proximity of human settlements, and variables such as extent of bush encroachment and wildlife and livestock grazing pressure (Senyatso 2010).
* Investigate the feasibility of re-introductions of captive-reared birds where the species has been extirpated.
* Further research into the severity of threats, and in particular collisions with power-lines, and ways to mitigate this, needs to be conducted.