Simon Thomsett on Vultures and Nairobi National Park (see edited version of article in newsletter)


Mixed group of vultures, Nairobi National Park. Credit STSmall Lappet-faced vultures. Credit ST

Small Ruppells vultures with a bone. credit ST

Vultures of Nairobi National Park Written by Simon Thomsett
For further information please feel free to contact the author on sthomsett@gmail.com
Simon suggests that individuals who want to help in vulture conservation can record nest sites, deaths, wing tag numbers, and report them to him. The Peregrine Fund (www.peregrinefund.org) has information on every species around the world under the Global Raptor Information Network.

Species
Nairobi National Park (NNP) has three commonly encountered vulture species, the Lappet Faced Vulture, the African White-backed Vulture and the Rüppell’s Vulture. The first two nest within the park while the Rüppell’s Vulture nests far out of the park on high cliffs. Two other species may occasionally appear: the Egyptian and Hooded Vultures.
The Bearded Vulture or Lammergeyer has been recorded in NNP some 40 years ago, perhaps a wanderer from the Hell’s Gate cliffs where they used to breed. Given that the Rüppells certainly make the shuttle run back and forth from this site the appearance of the Bearded Vulture was not that inconceivable. The White headed Vulture is conspicuous by its absence, especially as the habitat would seem to be ideal. However they used to occur on the Kapiti plains (in the 1940s an egg was taken there). Finally there is some compelling evidence of the seasonal occurrence of the Eurasian Griffon Vulture.
Ecological role
Vultures as a group used to be overlooked in the conservation management of wildlife. But today we are (or should be!) very aware of their role as janitors of eco-systems, specialising in refuse disposal. Some 80% of ‘meat on the hoof’ is eaten, not by lions, hyena and jackals, but by vultures. They can render a zebra carcass to bone within 30 to 40 minutes, consuming virtually every piece of flesh, tendon, sinew, cartilage, viscera and intestines that would otherwise rot. To watch them doing so is an engrossing if macabre way to pass one’s time. It is the thing of wildlife documentaries, understood as essential from the accompanying narration, but perhaps not acknowledged as such by those visiting NNP. Vultures in both protected land and livestock-rearing areas play a crucial role in habitat health. While their role in NNP may not be considered in the broader picture because of the small size of the park, they are as important here as they are anywhere.
Range
Often conservationists struggle to articulate one important concept when they talk of preserving wildlife, or rather the impossibility of conserving it when confined to small and fragmented ‘protected areas’. But in studying vultures the opposite is true : in a day they can traverse a number of parks spread out across the country. In so doing they highlight the need for all of us to accept our role in protecting what is around us wherever we are, for the sanctity of some distant place.
These vultures traverse large areas in their search for food, overflying NNP if required, in minutes on their way perhaps to Kapiti, Tsavo, Amboseli, Kedong, Mara or the Serengeti. The Peregrine Fund (PF), in collaboration with the Zoology Dept of The National Museums of Kenya, began a vulture marking programme in 2006 on the adjacent Athi Kapiti plains and the Maasai Mara Reserve. Patagial tags (markers attached to the wing) proved disappointing in that PF were sent back very few reports of these birds despite a few roosting and nesting within the NNP borders. We did have one juvenile Rüppell’s marked on Game Ranching move to the Mara and to western Laikipia, proving beyond doubt that no one park or reserve, no matter how big or well run, can on its own effectively protect vultures. In 2009 Corinne Kendall , Munir Z. Virani, Paul Kirui and I helped put satellite tags on vultures in the Mara. Corinne, a PhD student of Princeton University, has been able to document seasonal and daily foraging/nesting movements. The results again showed a link between virtually all major protected areas made by 3 species in their foraging activity, some birds flying from southern Serengeti to Athi Plains via the Mara, Ngurumans and Kedong Valley within a day or two, or to a few miles inland of our north coast. Somewhat predictably, despite the gargantuan overstocked livestock industries (and their inherent high mortality) outside of protected areas, these vultures preferred to forage in parks, conservancies and reserves. In other words those vultures we see in NNP may have flown in for the day from the Serengeti. This emphasises the need for us never to assume our protected areas as sufficient entities for conserving wildlife or those animals most important in the ecology of natural eco-systems. Just as the dispersal zone adjacent to NNP is crucial for the health of wildebeest and other plains grazing wildlife, so the vulture population is affected by, mostly, human behaviour in other protected areas far and wide.

Species summaries
Vultures are large flying birds that have to feed each day on the unpredictable and sporadic occurrence of large dead animals. They have to fly fast, high and far and compete against each other once they find food. They need to be smart, remember food sources, file a flight plan in their heads prior to take off, communicate intent to fellows, and follow others’ leads. Each species is separated from the other by flying abilities, energy use, nesting behaviour and how they eat to avoid competition. They are social – a lone bird is unable to forage as successfully as can a group.

The Rüppell’s Vulture is, on average, the largest and heaviest of these vultures weighing in at 7.5kg-9.5kg. It has a heavy wing loading and nests on cliffs. It can lift off and fly with ease on the up-currents offered by mountainous air warmed by the sun and once it has thermalled high it can set its wings and cover an enormous distance at 80-100kph. In these respects it is a specialised long distance flier who can outdistance and dominate the lesser, but closely related African White-backed Vulture. (These two species belong to the same genus and both are often referred to as Gyps). Its population appears to have a seasonal fluctuation in synchrony with large plains ungulate movements such as Wildebeest and Zebra. Such migratory movements have very recently been disrupted in NNP but they still occur on neighbouring ranches in Athi Kapiti and in the Mara / Serengeti Ecosystem. The Rüppell’s Vultures’ closest nesting site to NNP is Hell’s Gate National Park and Kwenia in the Kedong Valley. Each are some 80km away as the vulture flies, a distance covered in an easy hour or two. It is an extremely variable species with many morphs from near white to dark chocolate. About the only certain defining features are its large size and pale bill and pale eyes.
The African White-backed Vulture is now numerically the most abundant vulture commonly encountered especially outside of protected areas. Whether this was always true in our region is doubtful. It weighs 4.7kg-7.7kg and nests in tall groves of trees. It does not leap off cliffs in the morning to catch updrafts and it is a little less better designed to traverse the country each day. Its status is perhaps less secure for the simple fact that it nests in tall mature, and almost never in exotic, trees. It can tolerate a low level of ‘responsible disturbance’ from quiet passers by, but not the disturbance arising from wood cutting and the calls of livestock herders. Its nesting choice is often the target of charcoal cutters, changaa brewers, wood collectors and property developers. In NNP it nests in old Cape Olives in the western forests, and down the Yellow Fever drainage lines to Cheetah Gate. The total number of nests within the park are difficult to determine as most must surely be off the roads. But NNP (unlike most other parks) is fortunate in having resident nesting pairs and efforts to GPS each would be valuable. The species used to nest around the park, in Ololua Forest for example, and these have certainly drastically declined, although there are a few nests remaining in Karen Forest. They also nest in loose colonies in Athi Kapiti and just west of Orly in highland Kitengela/Ngong slopes. They are separable from all morphs of the larger Rüppell’s by their smaller size, black bills and dark eyes.

The Lappet faced Vulture may look more formidable, due to its large bill and square shaped stance but it is lighter than most Rüppell’s weighing in at 5-8kg (rarely 9kg). It is also more lightly wing loaded, being thus able to fly in less turbulent air earlier in the day from a low position. It may still occasionally breed near the old JKIA beacon, but its breeding status has dramatically declined, with some 5 pairs on nearby Athi Kapiti defunct since late 1990s. There is certainly a need to log each nest and keep good records of their breeding success. They usually breed on small but dense flat topped acacias or balanites and compete with Secretary Birds. It has too often been described as the axe-man of vultures, arriving early and cleaving the carcass asunder to allow lesser vultures a chance to eat the spoils. It is supposed to bully and intimidate all and take the major portion of the kill. In fact it is a specialist feeder preferring tendon, cartilage, skin, hooves and seemingly tough-to- digest pickings. It really doesn’t compete for meat and viscera with the Gyps vultures but may rely on them to find carcasses and fragment them. It also eats afterbirth and can occasionally kill newly born calves. It certainly associates with the high density population of cheetah on the Athi Kapiti, roosting nearby and following them for kills. Now with one cheetah in the park this behaviour is probably a relic. It swaggers and poses dreadfully, usually to others of its own kind. Juveniles tend to move together taking advantage of opportunistic abundance of food such as calving seasons. It is a species in decline outside of protected areas due to its low and easily disturbed nesting sites and its large territory requirements.
The Egyptian Vulture was once an easily seen species in the park with a pair nesting near Leopard Cliffs in the Mbagathi Gorge up until the mid 1990s. Another pair on nearby Lukenya Hill also became extinct a little later. This species has declined within the last decade throughout Kenya.
The Hooded Vulture used to be much more common, nesting in the 1970s in what was a forested Valley somewhere near where the Bomas of Kenya stands today. It may still straggle into the park. Why it seems to prefer much larger parks in Kenya and Tanzania is odd, given that they are like crows in nearby Entebbe, Kampala and Ethiopian towns. Here in highland Kenya they seem shy and wary of man.
Conservation
Being scavengers and highly beneficial to man one would suppose that vultures are well liked, encouraged and doing well. Vultures have received considerable attention of late, due in part to the furore over the demise of Indian Vultures, with the Kenya Raptor Working Group and the Peregrine Fund hosting such events as the International Vulture Awareness Day, and vulture conservation awareness programmes. In the 1980s there were an estimated 40 million vultures in India. Today there are 60 000. The results of such awareness raising events have been to highlight the species’ national importance as ecosystem managers. Nevertheless a recent poisoning event that took place in the Mara, weeks after a vulture meeting was held next door, underlines the lack of effective enforcement of conservation principles, and immunity to those that poison.
Predictably the widespread practise of poisoning hyena, jackal, lions etc has had a catastrophic effect on vultures. If 80% of carrion is eaten by vultures, then it follows that some 80% of poisoned food is eaten by them too. They mature and reproduce much slower than mammalian carnivores and cannot bounce back. The birds we marked are being recorded as dying at rates far beyond that needed to cause the extirpation of the entire population. Vast areas in Kenya are devoid of vultures. The poachers of Tsavo do not like vultures and call them ‘informants’ bringing KWS to the sites of their work. So they poison them deliberately. Incomers to wildlife areas from urban environments often fear all wildlife including vultures. To kill vultures is to them no crime for they are considered to be dangerous, filthy and disgusting.
But vultures are not disgusting. Observe them closely and understand the role they play. They are fine majestic animals who lord over all things across the entire continent, disregarding man-made boundaries and cleaning as they go.

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One response to “Simon Thomsett on Vultures and Nairobi National Park (see edited version of article in newsletter)

  1. Terrific, Simon! What do you hear from our Disney script? I’m in LA. Can and will give it a boost if necessary.; like propose a TV series. Maybe coming down there soon. Do you hear anything about Abu Dhabi Sheik Whatever leasing the entire Boma Plateau/Sudd animal migration? I heard they plan to do some falconry, mabye eagles. Look forward to hearing from you soon. As ever, Harry

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