Lake Natron is considered to be the world's most important breeding site for the Lesser Flamingo
(the Lesser Flamingo is on the World Conservation Union red list of threatened species). Lake Natron accounts for up to 75 per cent of the world's lesser flamingos.
The lake is the only regular breeding area in East Africa for the 2.5 million Lesser Flamingoes, whose status of "near threatened" is a consequence of their dependence on the single breeding location. As salinity increases, so do the number of cyanobacteria, and the lake can support more nests. These flamingoes, the single large flock in East Africa, gather along saline lakes in the region, where they feed on Spirulina (a blue-green algae with red pigments). Lake Natron is a safe breeding location because its caustic environment is a barrier against predators trying to reach their nests on seasonally-forming evaporite islands. Greater Flamingo also breed on the mud flats.
During breeding season, more than 2 million lesser flamingos (Phoenicopterus minor) use the shallow lake as their primary breeding ground in Africa. The flamingos' nests are built on small islands that form in the lake during the dry season.
Lake Natron is one of two alkaline lakes in that area of East Africa; the other is Lake Bahi. Both are terminal lakes that do not drain out to any river or sea; they are fed by hot springs and small rivers. As shallow lakes in a hot climate, their water temperatures can reach as high as 106 degrees Fahrenheit (41 degrees Celsius).
The lake has a surface area of around 1300 square kilometres and has no outlet other than by evaporation. Only about 400mm of rain falls in this area, much of which falls as 'phantom rain', a phenomenon by which the raindrops evaporate before they even hit the highly reflective surface of the lake. The evaporation rate has been calculated as being eight times the rainfall rate, the difference being made up by inflow from various seasonal streams and sodorous springs along the base of the escarpment.
The areas around Lake Natron contain some of the most amazing scenery in Africa. The combination of broad open plains, sheer rift escarpments, enormous freestanding volcanoes and the vast multi-coloured soda lake itself is utterly breathtaking.