Into Africa: February - April 2024 (part 5)

Sep 7

Written By Jumbo Williams

Section #5: Safari, East Africa

We flew from Nairobi to Tanzania’s Kilimanjaro International Airport near Arusha to join an 18-day “Birding and Big Game” safari of Tanzania and Kenya. We chose this tour because the itinerary covered a broad selection of East African Rift habitats.

The safari participants were 6 clients (all USA residents), an expert birding guide from UK, and a local birding guide/driver. The group travelled in a Toyota landcruiser that was customized for safari work but remained street-legal.

The group gathered at a lodge in the forested foothills of Mount Meru. From there, we drove south to Tarangire National Park. Next, we explored iconic Serengeti, Olduvai Gorge, and Ngorogoro Crater.

The long rains arrived and remained a significant aspect of our safari experience for the entire tour.

After revisiting the lodge near Arusha for one night , we crossed into Kenya at Namanga and went eastward to Amboseli National Park. From Amboseli, we had a long day’s drive, via Nairobi, to Castle Forest on Mount Kenya’s southeastern slopes. Descending onto Kenya’s central plateau, we journeyed north to Shaba and the adjacent Buffalo Springs Reserves. This is drier country, but was glowing fluorescent green from the recent precipitation. Leaving the highlands, we travelled southwest, dropping into the Gregory Rift to reach Lake Nakuru. On our final day, we returned to Nairobi.

Our guides were superb birders and they identified many birds that would have remained a mystery to us. The official species count for the safari was 485, bringing the total for our Africa trip to 667.

Africa’s Great Rift Valley

This complex system of rift valleys stretches approximately 4,300 miles from the Middle East to Mozambique. It is geologically active, and features volcanoes, hot springs, geysers, and frequent earthquakes. The region has highland forests, snow-capped mountains, savannas, wetlands, and lakes, which together with the rich volcanic soils and tropical location, support a spectacular abundance of life.

Plate tectonics

Throughout the Great African Rift, the continent of Africa is splitting in two. The African plate, sometimes called the Nubian plate, carries most of the continent, while the smaller Somali plate supports the Horn of Africa.

The two major rift valley systems are the Gregory Rift and the Albertine Rift (right figure, above). These rift valleys are dotted by volcanoes (left figure, above) such as Mount Kenya (extinct stratovolcano) in Kenya; Ol Doinyo Lengai (active volcano) and Mount Kilimanjaro (dormant stratovolcano) in Tanzania.

The Gregory Rift stretches from the Red Sea and the Arabian Sea to as far south as Mount Kilimanjaro. One of the most important features of the Gregory Rift is the Afar Triple Junction, found where the Horn of Africa straddles the Red Sea and the Gulf of Aden in the Arabian Sea. At the Afar Triple Junction, the Arabian plate, Nubian plate and Somali plate are all tearing away from each other.

Two arms of the Afar Triple Junction continue to widen in the process of seafloor spreading—the arm extending into the Red Sea and the arm extending into the Gulf of Aden. As these rifts continue, the narrow valley created by the Gregory Rift (the arm of the Afar Triple Junction located above sea level) may sink low enough that the Arabian Sea will flood it. Separated from Africa by this new strait, Horn of Africa (sitting on the Somali plate) would become a continental island, like Madagascar.

The Albertine Rift, also called the Western Rift, includes many of the African Great Lakes. Lake Tanganyika is the world’s second-deepest and second-biggest (by volume of freshwater) lake in the world. It contains hundreds of endemic species of cichlid fish, as do other freshwater Rift Valley lakes.

The African Rift formed in the Miocene approximately 25 million years ago; originating at the Afar triple junction and extending southwards over time. The eastern branch is thought to have formed earlier than its western counterpart.

Proposed cause of the Rift Valley system

The orientation of the rifts, highlands and associated flood basalts in the Afar region indicate that the East African Rift most likely formed as the result of elevated heat flow from the asthenosphere beneath Kenya and Ethiopia. This increased heat caused the regions to uplift resulting in stretching and fracturing of the brittle continental crust (see domes illustrated in figure below). Flood basalts erupted through fissures and a series of normal faults were generated, creating the classic ‘horst and graben’ morphology of elongate basins and associated highlands, which now make up the rift valley. The source of this elevated heat flow is under debate but most geologists agree that it is related to mantle plume activity heating the overlying crust and causing it to expand and fracture.

Adapted from: National Geographic, Wikipedia & The Geological Society websites

Figure showing plate boundaries and uplifted domes.

Mount Meru

Mount Meru is a dormant stratovolcano; the last eruption occurred in 1910. Much of the mountain's height was lost about 7,800 years ago due to a summit collapse. Currently, it stands 14,968 ft above sea-level. Our lodge was in the wooded foothills, alongside a vigorous mountain stream, and about an hour’s drive from Arusha town.

Tarangire National Park

The next stop was Tarangire and we thoroughly enjoyed our time there. It is a large park with luxurious riverine vegetation bordering the Tarangire river. Away from the river there is extensive thornveld woodland, iconic baobab trees, and broad swaths of open grassland.

Storm and baobab, Tarangire National Park

Flooded backwater lagoon, Tarangire river

Yellow-collared Lovebirds living up to their name

Laundry at Masai village near Lake Manyara

Southern Ground Hornbills settling down for the evening rains

Long Rains

From late March and into May, torrential rains, floods and landslides pummeled Kenya, Tanzania and Burundi. After leaving Tarangire, we visited a Masaai village and then ascended the Gregory escarpment to the Ngorongoro highlands. That night it rained continuously. The locals said they had never known rain like it, and we awoke to find the roads all blocked by flooding and our vehicle abandoned amid the muddy waters. It was towed to the lodge, drained of water, cleaned and a mechanic worked on the engine. That night it poured again, but by midday, the water streaming over our exit road had subsided sufficiently for a tractor to pull our Toyota to other side.

Awaiting our turn to be towed by the tractor.

Serengeti National Park

One striking feature of the Serengeti is the flat, treeless plains that cover the southern third of the national park. During the Pleistocene age about 3 million years ago volcanic ash blown from the Ngorongoro highlands covered what are now the plains and as a result formed a calcareous hardpan less than a meter below the soil surface. This hardpan is impenetrable to roots and the shallow soil dries out quickly, making it impossible for trees to grow.

The migrating herds move to the southern grasslands during the wet season. The shallow hardpan just under the surface of the plains retains rainwater, allowing grasses to thrive. The incredible numbers of grazing animals in Serengeti National Park means that during the rainy season most of the grasses are eaten multiple times. If the grass is cut short by grazing animals, it will rapidly re-grow and the new forage will contain higher levels of nutrients and water. Consequently, the herbivores favorably modify the plains - the intense grazing pressure of two million ungulates converts the grasslands to a highly nutritious, highly productive state that supports the animals during the calving season.

As the dry season approaches, the seasonal waterholes dry up and the grass turns to yellow, then golden color. This is the time for the wildebeest to begin the annual northward trek to wetter areas of the park. Grant’s gazelle, warthog and ostrich remain behind to feed on the dried grasses on the plains. Only species that can do without water for lengthy periods can live on the plains during the dry season.

Adapted from: https://www.serengeti.com

Top row; Left: Plains Zebra, Right: Common Wildebeest

Bottom row; Left: Hartebeest, Right: Tsessebe

Serengeti life

Oldupai Gorge

The Masai word oldupai means "the place of wild sisal", a plant species that is abundant in the area. Oldupai is a steep-sided ravine in the Great Rift Valley and is located in the eastern Serengeti Plains, within the Ngorogoro Conservation Area. Exposed within the sides of the gorge is a remarkably rich chronicle of human ancestry and the evolution of the Serengeti ecosystem.

Homo habilis, a tool-maker and early early human species, occupied Olduvai Gorge approximately 1.9 million years ago (mya); then came an australopithecine, Paranthropus boisei, 1.8 mya, followed by Homo erectus, 1.2 mya. Homo sapiens, which is estimated to have emerged roughly 300,000 years ago, is thought to have occupied sites in the gorge 17,000 years ago.

Anthropologists Mary and Louis Leakey worked at Oldupai for more than 30 years. It was recognized as a UNESCO World Heritage Site in 1979.

Oldupai gorge, looking west. It is about 34 miles in length and 300 feet deep.

Nutcracker Man. The Oldupai Gorge Museum is situated near the gorge and is well-worth visiting.

Ngorogoro Crater, Nature’s perfect bowl

The vast Ngorongoro Conservation Area covering 3,200 square miles is a World Heritage Site that protects Earth’s largest intact volcanic caldera. Ngorogoro Crater has forests, lakes, grasslands, swamps and rivers, and is perhaps less impacted by human activities than other East African wildlife regions. Between 25,000 and 30,000 large animals reside in the crater - one of the planet’s densest populations of large mammals. After the heavy rains, the marshes were overflowing, and we found many species of water-associated birds.

Gray-hooded Gull with fish. Lesser Flamingoes in the background.

Greater Flamingoes engaged in what seemed to be agonistic behavior.

Gray Crowned Cranes are generalists and eat seed heads, fresh tips of grasses, insects, and other small animals such as lizards, frogs and crabs.

Amboseli National Park

Amboseli comes from a Maasai word meaning "salty dust place". The park falls in the rain shadow of Mount Kilimanjaro and is a semi-arid savanna, with habitats ranging from lake shoreline, wetlands with sulphur springs, savannah and woodlands.

Kilimanjaro. This brief view was our only opportunity to see the mountain.

The Amboseli basin formed during the Pleistocene when the area was covered by a lake. Vast deposits of lacustrine silts and clays were laid down, reducing the relief of the topography and constricting drainage. The lake has since receded, but soils remain saline and alkaline since the basin still acts as the sump of the closed Amboseli drainage system.

Amboseli provides migratory corridors for wildlife. For example, it facilitates movement of large mammals, including elephant, eland, buffalo, African wild dog, zebra, impala, lion, cheetah, leopard and hyena to & from the montane forests of Kilimanjaro.

Over 400 species of birds have been recorded and the park is famous for its elephant population which has been intensively studied by researchers such as Joyce Poole, Katy Payne and Cynthia Moss.

Kori Bustard, male in full display at lek

Water Thick-knee with half a frog. It had three chicks in attendance.

Castle Lodge, Mount Kenya

Nestled in the misty slopes at the foot of Mount Kenya (17,057 feet), Castle Forest Lodge is a lovely refuge from equatorial heat. It was built in 1910 and renovated in 2000, We birded near the lodge and along montane forest paths.

Pin-tailed Whydah, male (left) displaying to female (right)

Shaba and Buffalo Springs Reserves

Near Isiolo city in northern Kenya, there are three reserves: Samburu, Shaba and Buffalo Springs. These protected areas consist of rugged mountains, “Acacia” woodland, plains of old lava flows, and contain olivine basalt soils. The Ewaso Nyiro River, with its associated riverine vegetation, traverses the region. There are isolated springs. Buffalo Springs is named after an oasis of clear water at its western end.

Rosy-patched Bushshrikes singing among Donaldson Smith's Sparrow-weaver nests

Northern Giraffe, subspecies *reticulata*

Lake Nakuru National Park

The park was established to protect vast flocks of flamingoes. It covers 73 square miles and centers on Lake Nakuru, an alkaline Rift Valley lake. It is situated at an elevation of 5,755 feet, and has a maximum depth of the lake is only 6 feet. The surrounding landscape includes grasslands, marshes, copses of yellow fever trees, and hills with granite cliffs. The park is fenced to contain and protect the large mammals, including a substantial number of white and eastern black rhinos.