South Africa's bustards and korhaans are in trouble, with six of the country's ten species listed in The Eskom Red Data Book for Birds of South Africa, Lesotho and Swaziland (Barnes 2000). They are threatened by a variety of factors, including habitat destruction and collision with power-lines". BirdLife South Africa is concerned about the precarious conservation status of the country's bustards and korhaans and therefore convened a workshop in Johannesburg in May 2009 to discuss their conservation status, threats and necessary conservation measures.
The situation is quite dire for several species. Populations of Ludwig's Bustard and Denham's Bustard are probably in decline due to a single mortality factor, collisions with the cables of power-lines. These birds fly in groups during low light conditions and due to their limited manoeuvrability are not able to avoid electricity cables in their flight path. Recent studies have found that, on average, about one Ludwig's Bustard collides per kilometre of transmission power-line (>132 kV) per year. There are approximately 16,000 km of transmission power-lines criss-crossing the Karoo, so we could be losing more than 10,000 birds a year.
It is unlikely that the Ludwig's Bustards can sustain these large numbers of annual mortalities, especially considering that its global population has been estimated to only number between 56,000 and 81,000 individuals.
Another bustard in trouble is the South African endemic Blue Korhaan. It mainly inhabits grasslands in the central and eastern regions of South Africa and is severely threatened by afforestation, crop farming, overgrazing, burning, urbanisation and mining. Analyses of information from the Coordinated Avifaunal Roadcount Project (CAR) suggest that this korhaan has declined in both numbers and range during recent years.
The White-bellied Korhaan, a species that is restricted to the grasslands and open thornveld, is listed as Vulnerable in the South African Red Data Book. It prefers tall, undisturbed grassland, and is thus threatened by human population pressure and inappropriate farm management. There has been much debate as to whether the South African population is a separate species (i.e. Barrow's Korhaan) and, if so, there is even more of an obligation for South African conservationists to attend to the numerous threats which are impacting on this threatened species.
BirdLife South Africa's White-bellied Korhaan Project
The scarce and elusive White-bellied Korhaan Eupodotis senegalensis is easy to identity; this korhaan is the only in the region with a white belly. It also has a pinkish-red bill. In the male the buffy nape and blue-grey foreneck are characteristic. In its congener, the Blue Korhaan Eupodotis caerulescens, the neck and underside is a rich blue-grey. Groups often give their position away by their croaking calls, usually heard at dawn, but even then can be very difficult to see.
The White-bellied Korhaan is more vocal and conspicuous when it is courting and contesting territories in spring (mainly September-November). Neighbouring groups frequently answer each other and may be spotted flying low over the grasslands in pursuit of competitors. It can be very secretive when breeding or when accompanied by small chicks.
The White-bellied Korhaan is a threatened near endemic to the Grassland Biome. It is currently listed as "Vulnerable" in The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland (Barnes, 2000), because of having a restricted distribution and small population size (probably not more than 5 000 individuals).
Habitat suitable for the White-bellied Korhaan has been altered at a dramatic rate and its area of occupancy is estimated to have declined by at least 20% over the last three generations, suggesting concomitant population declines, qualifying it as Vulnerable. The subpopulations are becoming highly fragmented. This decline is likely to continue over the next 20 years, unless proactive measures to prevent habitat destruction are implemented. Taken from The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland (Barnes 2000).
Preliminary analyses from the Coordinated Roadcount Project (CAR) and of SABAP1 and SABAP2 data suggest the South African population of this korhaan species has considerably declined in both numbers and range during recent years.
The main threats, that similar affect a number of other bustard species, appear to be habitat loss and degradation due to:
- commercial afforrestation,
- intensive crop farming,
- open-cast mining, and
- habitat modifications as a result of growing human populations.
The local subspecies of White-bellied Korhaan is a scarce and elusive endemic resident to southern Africa with a restricted range centered on the central and eastern regions of South Africa and south-western Swaziland. There are isolated records from Lesotho and Botswana.
The White-bellied Korhaan occurs sparsely in both the Grassland and Savanna Biomes. It is often most common in transitional areas between different habitats (ecotones), and undisturbed, rolling grassland dotted with some tree cover and where termite mounds are plentiful (especially on rocky ground) seems to be considered prime habitat by this species.
Unlike the Blue Korhaan, which frequently strolls about in the open, the White-bellied Korhaan prefers taller grass, from which it rarely emerges. During winter the korhaans sometimes venture out from tall grass cover to forage in recently burnt areas.
Research into the White-bellied Korhaan’s requirements, particularly its affinity for taller undisturbed grassland, deserves investigation. Its nesting habits are poorly known. It is speculated that the bird moves to lower-lying areas during winter. However, this remains unsubstantiated.
The taxonomy of Eupodotis senegalensis barrowii (J.E. Gray 1829) has been debated for some time: some authorities maintain that the southern African form is a full species, i.e. Barrow’s Korhaan Eupodotis barrowii, endemic to southern Africa. However, pending consensus on its taxonomic position, Barrow’s Korhaan is treated by most as a local subspecies of the White-bellied Korhaan (or Bustard) Eupodotis senegalensis which is widespread throughout the African continent. The so-called Northern White-bellied Korhaan, recorded from Angola, Zambia and as a rarity in far northern Namibia, is also regarded as a subspecies, Eupodotis senegalensis mackenziei (C.M.N. White 1945). Given the White-bellied Korhaan’s poor conservation status, taxonomic investigation of its specific status is warranted. If the South African population is a separate species, there is even more of an obligation for South African conservationists to attend to the numerous threats which are impacting on this threatened species.
Monitoring and Research
A PhD project is being undertaken by Dewald du Plessis to study the biology, taxonomy and conservation of the White-bellied Korhaan Eupodotis senegalensis in South Africa. Dr Craig Symes from the University of Witwatersrand and Dr Hanneline Smit-Robinson from BirdLife South Africa, supervise the project, which is based on the Diamond Route properties of Telperion and Ezemvelo Nature Reserve. By understanding the different aspects of the biology, as well as the taxonomic status, of this species in South Africa, biologists, conservation bodies and decision-makers will be able to make informed decisions about the conservation of this important grassland species and related habitats in which it occurs.
For more information about the research project and the White-bellied Korhaan, please contact Dewald du Plessis on firstname.lastname@example.org, or Dr Hanneline Smit-Robinson, Conservation Manager/Oppenheimer Fellow of Conservation, BirdLife South Africa on 011 789 1122 or email@example.com
BirdLife South Africa is very grateful for the incredible support this project is receiving from its members, bird clubs, bird tour operators and other companies. Part of the research costs are covered through funding from the De Beers Diamond Route, E. Oppenheimer & Son and the National Research Foundation.
Through the efforts of a volunteer, Niall Perrins, over R150,000 has been raised since January 2011. The funds will be allocated to the costs of the genetic analyses and to purchase field equipment.
Funding has also been received to support the purchase and placement of GPS tracking devices on White-bellied Korhaan individuals in the Bronkhorstspruit grasslands area. These funds have kindly been provided by Birding Africa, BirdLife Sandton and Ocean Breeze Food Merchants (Nic Efthimiades - BirdLife Northern Gauteng). This aspect of the project will assist with our work to study habitat use and movements during the breeding and non-breeding seasons. Attempts will be made to investigate movements between sub-populations, and populations that may have become recently isolated. A web-link on the BirdLife South Africa website (and the sponsor website) will show the movement of the individuals after the tracking devices have been fitted. The sponsors will also have an opportunity to name their bird.