South and eastern Kenya includes the borderlands south of Nairobi, the majority of the land either side of the Nairobi – Mombasa road, and is bordered on its eastern flank by the coastal strip and in the north by the Tana River. From a wildlife point of view, the area is home – in the south – to Lakes Magadi and Natron, the Nguruman escarpment, the Shampole Conservancy, Amboseli, the Chyulu Hills and Tsavo West, and – in the east – to Tsavo East, South Kitui and the Tana River Primate Reserve. In addition to these public wildlife sanctuaries, a number of Masaai owned ranches guarantee vital migratory corridors.
Bisected by the Nairobi -Mombasa road, the area is either arid or very arid. Generally speaking, the further east and south one gets, the drier and hotter the climate. So, just out of Nairobi, in Athi River, the annual average temperature is 20°C, the average annual rainfall 744mm. Here, April is the wettest month, with an average yearly rainfall of 157mm, with May and November close behind. Maximum average temperatures rarely exceed 26°C. Contrast these figures with, first, those of Shampole, just 120 km south of Nairobi, with temperatures in the thirties and an annual rainfall level of 479mm, and to those of Amboseli, where annual rainfall figures rarely exceed 300mm, and temperatures are only slightly lower than those of Shampole.
The effect of a dry, hot climate on the area’s flora depends also on permanent water sources, and on local topographical influences. Thus, while it is true to say that as you descend south or south-east out of Nairobi, the country is characterised by a series of semi-arid to very arid habitats, by Acacia woodlands, bush, scrub and, finally, in areas like Garissa, desert, there are areas whose position – altitude or proximity to a permanent water source – makes for an ecosystems all of their own. Chief among these are the south Rift Valley’s the Nguruman escarpment, the Chyulu Hills, Taita Hills, Amboseli and the Tana River, all of which contribute to the area’s occasional anomalies – montane grasslands and forest (the Nguruman and the Chyulu Hills) swamp (Shampole and Amboseli, for example) or riverine forest (the Tana River, for example). Much of the area sits on Yatta Plateau, the world’s longest lava flow, and is served by the saline lakes Magadi and Natron and by a number of hot springs, salt licks and smaller volcanic lakes.
The movement of animals in the area is dictated by the weather. The dry season – January to March and May to September – is best for viewing animals, with large numbers of herbivores and carnivores congregating about permanent water sources. Wildlife is generally dispersed and – due to increased cover – harder to spot during the wet season, the long rains occurring from March through to May, the short rains from October to December. Our main south-east Kenyan destinations – the Shampole Conservancy, Amboseli, the Chyulu Hills and the Taita-Tavita district – are all part of the same Amboseli biosphere, with Amboseli as its core, surrounding areas a buffer zone, and zonal border lands acting as transition zones. Seasonal migratory herbivores include wildebeest, elephants and zebra, while resident herbivores include buffalo and impala, with carnivores such as lion, hyena and cheetah prepared to travel when necessary.