Open image gallery
The regional population of Saddle-billed Stork Ephippiorhynchus senegalensis satisfies criterion D for regionally Endangered (population size less than250 mature individuals).
Saddle-billed Storks occur in suitable habitat throughout sub-Saharan Africa (del Hoyo et al. 1992), but in South Africa (at the southernmost extreme of the global range), the species is restricted to subtropical areas in association with large, perennial rivers and other waterbodies (Benn 1997). Kruger National Park and adjacent areas (IBA SA002) form the core of the species' range in the region, together with three Zululand IBAs namely iSimangaliso Wetland Park (IBA SA058), Mkuze Game Reserve (IBA SA057) and Hluhluwe-iMfolozi Park (IBA SA060). Birds are also resident along the Limpopo River, west of Kruger National Park. In Swaziland, Parker (1994) mentioned that the species occurred sparsely in the Mbuluzi River system in the north-east of the country. Adults tend to be resident with no evidence of seasonal movements (Benn 1997) but immatures disperse widely. Records in North West, Free State and elsewhere are likely to be immature or vagrant birds.
The global population in 2002 was estimated at 10 000-25 000 birds (Dodman and Diagana 2006). Taylor et al. (1999) estimated there to be 100-200 mature individuals in the region. A recent survey by van den Hoven and Reily (2012) reported a minimum of 40 mature individuals in the southern portion of Kruger National Park. Extrapolated to the entire park, the population may be in the order of 100 mature individuals. Although regular sightings are reported from sites in northern KwaZulu-Natal as well as along the Limpopo River, the number of birds in the region is unknown. If an estimate of 30 mature individuals is assumed for the Limpopo River and northern KwaZulu-Natal each, the total regional population would be c. 160 mature individuals. The confidence in this regional population estimate is medium.
The global trend is suspected to be decreasing (Dodman and Diagana 2006). Historically, the species has never been abundant and the slow rate of recruitment, coupled with naturally low densities, predisposes the population to local extinction risks (Benn et al. 1995). Based upon the published generation length as well as the estimates provided by Taylor et al. (1999) and the current revised estimate, the reduction over three generations (48 years) would be c. 12%. The population trend would therefore be slightly decreasing although this is dependent upon the accuracy of the population estimates provided. The confidence in this estimate is low due to the unknown generation length.
The most significant threat to the species is loss of suitable habitat due to a decline in water quality and quantity of the rivers and other waterbodies along which it occurs. This may be a result of water extraction and pollution due to activities such as water provision to urban settlements, agricultural-, industrial- and mining activities and the construction of impoundments within catchments. Similarly, severe drought conditions within the range of the Saddle-billed Stork could also significantly reduce the extent of available habitat. The impact of agricultural chemicals has yet to be determined but could conceivably threaten this species (Monadjem et al. 2003).
The core of the species' range in South Africa falls within Kruger National Park, which is a well-protected conservation area. Current efforts to prevent further degradation of river and wetland habitats within its range should also benefit this species. It is listed under Schedule 2: Specially Protected Wild Animal under the Limpopo Environmental Management Act No 7 of 2003. The Saddle-billed Stork is listed as Endangered under the South African National Environmental Management: Biodiversity Act (Act 10 of 2004) and as Endangered in Swaziland and is protected under the Swaziland Game Act of 1991.
Adequate protection of known breeding sites is an important conservation intervention. Implementation of an awareness programme involving all stakeholders and highlighting the threats facing this species is necessary. The potential impact on this species should be considered during the assessment of development applications in catchments.
* Regular monitoring and field surveys, particularly in northern KwaZulu-Natal, are required in order to more accurately determine the regional population and conservation status.