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The regional population of Swamp Nightjar Caprimulgus natalensis has been quantified at less than 1 000 mature individuals. In addition the species qualifies as Vulnerable under the range-size criterion, having an Area of Occupancy less than 2 000 km2 combined with a severely fragmented range.
The Swamp Nightjar has a geographically extensive but exceptionally fragmented distribution throughout the Afrotropics (Fry et al. 1988). The regional sub-population (contiguous with a small population in far southern Mozambique; Parker 1999) is largely isolated from the remainder of the African range, the next closest populations being in north-western Zimbabwe and northern Botswana (Davies and Allan 2005). Within South Africa, the species is mainly confined to KwaZulu-Natal (Harrison et al. 1997, Parker 2000), with a relict, little-known population in Eastern Cape (Quickelberge 1989). It is mainly restricted to the coastal plain north of the Tugela River, with a stronghold in the iSimangaliso Wetland Park. Formerly, it had a much more continuous range throughout coastal KwaZulu-Natal, with historical records from the Durban and Pinetown areas (Stark and Sclater 1903, Maclean 1997), Umzumbe (Ditsong National Museum of Natural History, egg collection) and Umzinto and Ixopo districts (Aubrecht et al. 2004), but had largely disappeared from these areas by the 1970s (Cyrus and Robson 1980).
A small population may still exist on the Oribi Flats, southern KwaZulu-Natal, as a pair has been recorded on Minnehaha Farm, Oribi Flats (30°40'S, 30°15'E) for many years (M Neethling pers. comm.). It also appears on the reserve checklist for Oribi Gorge Nature Reserve, although there are no published records for the reserve within the last 30 years and indigenous grassland is very limited within the reserve boundaries. There are records from Umtamvuna Nature Reserve, Port Edward (Cyrus and Robson 1981), and a few birds were found in the Rennie's Beach grasslands, just outside Port Edward, in 2011 (G Nichols pers. comm.). In the Eastern Cape, this nightjar is known from Mkambati Nature Reserve (Christian 2003, 2006) and the river valleys between Mkambati and the Umtamvuna River (Quickelberge 1989).
There are no reliable global or regional population estimates. Johnson et al. (1998) provided estimates for KwaZulu-Natal IBAs; totalling these suggests a figure of 530-780 birds. Parker (2000) estimated a total South African population of c. 1 000 birds, but this did not include the Eastern Cape population (V Parker pers. comm.). Although the Swamp Nightjar has suffered a major range contraction in KwaZulu-Natal, most of the populations are now protected within conservation areas (e.g. iSimangaliso Wetland Park). The remaining population outside of protected areas in the province is likely to number less than 100. The size of the Eastern Cape population, which occurs mainly in areas under subsistence agriculture and pastoralism, is uncertain, but is likely to be less than 200 birds. The total regional population is conservatively estimated to be less than 1 000 birds. The proportion of the regional population outside of protected areas, and therefore likely to come under threat from impacts such as loss of habitat, is roughly 25%. Confidence in this estimate is low.
The main sub-population in northern KwaZulu-Natal has remained stable since the 1970s (Cyrus and Robson 1980, 1981) versus Maclean (1997) and SABAP2. Outside of IBAs, the area, extent and quality of habitat has decreased and it is inferred that this has had negative impacts on the population. The isolated Eastern Cape population is likely to be declining owing to increasing human population and pastoral and agricultural pressures, but the paucity of accurate data means that this conclusion requires corroboration. The confidence in this estimate is low.
Main threats are loss of habitat, due to agriculture (especially sugarcane farming, but also subsistence agriculture in Maputaland), urban development along the KwaZulu-Natal coast, afforestation for timber plantations, wetland drainage, and, potentially, dune mining. Excessive grazing and burning of grasslands may also be detrimental to the Swamp Nightjar. The species is relatively seldom killed by vehicles.
Currently no conservation actions exist for this species.
A Species Action Plan is recommended. Approximately 75% of the regional population of Swamp Nightjar now falls within conservation areas, with iSimangaliso Wetland Park being of particular importance. If these can be preserved, the status of the nightjar within the country should be secure.
* Better estimates of all populations are required, especially those in the Oribi Flats area and Eastern Cape.
* Research is required on the microhabitat preferences, including preferred grass height, density and species composition, and grazing and fire burning levels.