Lake Ol’Bolossat

Lake Ol’ Bolossat lies at an average altitude of 2,340 meters above sea level, beneath the dramatic backdrop of the Aberdare or Nyandarua mountain ranges. Covering an area of about 90 square kilometers,  lake  Ol’ Bolossat is a unique ecosystem whose variety of habitats makes it rich in biodiversity. The surrounding climate is semi-humid and strongly influenced by the highland topography of the Kinangop Plateau and the Ol’ Kalou/Ol’ Joro Orok plateaus, where slopes give way to rolling hills and shallow depressions.

Positioned close to the Great Rift Valley, Lake Ol’ Bolossat sits along one of Kenya’s most important migratory bird flyways, providing a vital feeding, roosting, and wintering ground for Palearctic migrants. It is also the source of the Ewaso Nyiro River, which flows north from the Aberdares to sustain ecosystems and communities across Laikipia, Samburu, Isiolo, and Garissa Counties.

The lake plays a crucial role in supporting both people and wildlife. It supplies clean water to Nyahururu town and nearby communities, provides grazing and fishing grounds, and supports large numbers of hippopotamus alongside more than 150 bird species. Birding enthusiasts often stop at nearby Thomson’s Falls, where special species such as the Slender-billed Starling and African Black Duck are sought after.

Ecologically, Lake Ol’ Bolossat’s wetlands are invaluable. Often referred to as the “kidneys of the landscape,” they regulate the hydrological cycle, filter pollutants, recharge groundwater, mitigate floods, and provide habitats for diverse flora and fauna. Beyond their ecological function, lakes such as Ol’ Bolossat enrich human life—supplying water, offering livelihoods, and creating green recreational spaces that make cities and towns more habitable.

Bird Highlights in Lake Ol’ Bolossat

Lake Ol’ Bolossat is one of Kenya’s most important wetlands for both resident and migratory birds. The lake provides vital breeding, feeding, and wintering grounds for ducks, geese, and other waterbirds. It is particularly renowned for hosting significant populations of two globally threatened species:

• Sharpe’s Longclaw – a high-altitude grassland endemic and globally threatened bird, with a stronghold population around Ol’ Bolossat.
• Grey Crowned Crane – the lake supports Kenya’s second-largest population, with one of the highest breeding pair densities recorded across the species’ range.

Birding here is best done on foot along the lake’s shores, where flocks of ducks and geese concentrate, and the backdrop of the Aberdare Mountains creates a stunning setting. A short walk can yield extraordinary diversity, from grassland specialties to large concentrations of waterbirds and raptors.

Notable Birds of Lake Ol’ Bolossat

• Waterbirds & Ducks: Little Grebe, Great Cormorant, African Darter, Spur-winged Goose, Knob-billed Goose, African Pygmy Goose, White-faced Whistling Duck, Fulvous Whistling Duck, Maccoa Duck, Red-billed Duck, Hottentot Teal, White-backed Duck, Yellow-billed Duck, African Black Duck, Northern Shoveler, Northern Pintail, Garganey, Common Teal, Eurasian Wigeon, Southern Pochard.
• Herons, Storks & Allies: Dwarf Bittern, Little Bittern, Black-crowned Night-Heron, Madagascar Squacco Heron, Black Egret, Goliath Heron, Hamerkop, White Stork, Abdim’s Stork, Black Stork, Woolly-necked Stork, Saddle-billed Stork, African Spoonbill.
• Flamingos: Greater Flamingo, Lesser Flamingo.
• Rails, Crakes & Allies: Red-chested Flufftail, African Crake, African Snipe, Black Crake, Purple Swamphen, African Water Rail, Red-knobbed Coot, Lesser Moorhen, Lesser Jacana.
• Raptors: African Fish Eagle, African Marsh Harrier, Long-crested Eagle.
• Grassland & Wetland Songbirds: Levaillant’s Cisticola, Wing-snapping Cisticola.

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