This coastal area comprises a private nature reserve of 400 ha and a saltworks. It lies adjacent to the sea on the central Namib desert coast and has been extensively altered to create numerous evaporation ponds. Immediately inland lie the gravel-plains of the Namib desert. The saltworks are situated about 7 km (4 miles) north of Swakopmund, off Route 76 to Terrace Bay. Production of the concentrated brine at the saltpan, known as Panther Beacon, began in 1933, but by 1952 the salt source was exhausted. Seawater has since been pumped into open evaporation and concentration ponds from which crystallized salt is removed with mechanical scrapers. The pans are shallow and of varying salinity. A large wooden commercial guano platform covering 31,000 m² has been built in one of the northern pans. Apart from a few halophytes, the saltworks are devoid of vegetation.
See Box for key species. Mile 4 occasionally supports massive numbers of waterbirds. The guano platform has supported up to 700,000 Phalacrocorax capensis in the past, and an average of 45,000 birds has been supported in recent years. Cormorants aside, the area may support more than 50,000 other waterbirds, including large numbers of Phoenicopterus ruber and P. minor, Haematopus moquini, and up to 100,000 Sterna hirundo. Breeding species include Sterna balaenarum and Charadrius pallidus.
Non-bird biodiversity: Brown hyena Hyaena brunnea (LR/nt) occurs at the nearby Swakopmund dump and scavenges along the beaches in this area.
BirdLife International (2020) Important Bird Areas factsheet: Mile 4 saltworks. Downloaded from http://www.birdlife.org on 28/11/2020.