Rationale
(Changed due to Genuine change; new or better information available)
Abdim's Stork Ciconia abdimii is a non-breeding migratory visitor to the region. The species has been described as locally abundant, and forms spectacular pre-migratory flocks of thousands of birds. However, recent evidence suggests that it is in decline, but the reasons for this are not documented, and it is unclear whether factors adversely affecting Abdim's Stork are occurring on its breeding grounds, non-breeding grounds or while migrating. As a precautionary measure, the species is assessed as regionally Near Threatened; it is hoped that further investigation will provide a clearer insight into the conservation of Abdim's Stork in the region.
Distribution
The species is an intra-African migrant, breeding in a wide band south of the Sahara from Senegal in the west to Ethiopia and Somalia in the east (Anderson 2005, Hancock et al. 2010). From May to August, the eastern population migrates to southern Africa, with arrival often coinciding with the onset of summer rains in November-December (Herremans 1994). Within the region the Abdim's Stork has been described as locally common to abundant in North West, Limpopo, Free State and Mpumalanga provinces (Anderson 1997), with localised movements in response to environmental cues such as food availability (Anderson 1997). Large flocks gather prior to migration in March-April, although some birds have been known to overwinter in South Africa. Comparisons of SABAP1 and SABAP2 data indicate that since 1993 the species has undergone a contraction in its former range within the region. This is particularly evident in Mpumalanga and other eastern areas.
Population
The global population was estimated at 300 000-600 000 mature individuals (Dodman and Diagana 2006). Estimating the number of birds in the austral summer is extremely difficult owing to regional movements. Although a decline in AoO is apparent, this does not necessarily imply a linear and corresponding decrease in population size. Furthermore, the number of birds in the region may be influenced by environmental conditions throughout the non-breeding range (DG Allan pers. comm) and may fluctuate naturally from year to year. The regional population, that is the number of migratory birds that visit the region in the austral summer, has not been quantified.
Population trend
The global population is thought to be in decline due to habitat destruction throughout the African breeding range, although the rate of decline is not known (BirdLife International 2014). Anderson (1997) made mention of declines in South Africa due to habitat degradation which has reduced the amount of natural grassland available to the species. The amount of habitat deterioration has almost certainly increased in the past two decades, which could have resulted in a continued decline in the number of birds in the region. The rate of decline is not known.
Threats
Migratory species face a diverse range of threats spread across the migration cycle (Kirby et al. 2008). Unfortunately, limited research has been done on the conservation of Abdim's Stork and it is uncertain whether threats causing the apparent decrease in numbers occur on the breeding grounds, on the non-breeding range, on migration routes, or a combination of the above. Habitat loss is believed to be one of the primary threats, mainly from urban development, bush encroachment and agricultural activities (Anderson 1997, BirdLife International 2014). It has been suggested that the control of invertebrates may be a threat (Coulter et al. 1989), although this needs to be investigated in light of recent bans on pesticide use in range states. The species is used for medicinal purposes in Nigeria (Nikolaus 2001).
Conservation
Underway
No direct conservation measures are currently underway.
Proposed
The species may be affected by threats on the breeding grounds, in the non-breeding range and at stopover sites in between, making it vulnerable to the effects of environmental change on a large geographical scale. Therefore, any conservation actions that may be informed by the research questions proposed here, will need to be implemented in close liaison with BirdLife International, as well as other stakeholders such as the scientific council and working groups of the Convention on the Conservation of Migratory Species of Wild Animals.
Research
* An accurate estimate of the size of the breeding population, as well as a the extent of the breeding range, is required.
* An evaluation of population trends is needed.
* Threats faced by this species should be identified, and their relative severity and scope evaluated.
* An assessment of whether threats to the species are on its breeding grounds, along migration routes, or on the non-breeding grounds is recommended.
