Over Che past 24 years, the primate population of Diani 
has undergone dramatic fluctuations. From 93 colobus 
monkeys/km 2 in 1972 (Moreno-Black and Maples, 1977) 
the numbers rose to 156/km 5 in 1989 (Frankfurt 
Zoological Society. 1989) and dropped to 73/km 2 (this 
study ). This trend is also reflected in the Sykes’ monkeys, 
which increased from 104/km 1 in 1972 to 230/km 2 in 1989 
and dropped to 78/kin 3 by the time of this study. These 
trends reflect the huge loss of forest area (75%) between 
1972 and 1 989 that may have resulted in the remaining 
forest patches. The subsequent decline in population 
reflects the population subsiding as it approaches a 
carrying capacity for the forest area. Despite its local 
importance, in comparison to other sites, the Diani forest 
primate biomass density' is quite low at only 496 kg/km. 
compared to 709 kg/km for Itun. Zaire (Thomas. 1 992) 
and 1.034 kg/knr in Lomako (McGraw. 1994). Diani. 
however, contains the highest known Colobus 
angolensis densities of between 24/km 2 and 156/km : 
versus 5.8/km 2 in Lomako and 7 7/knTin Itun. However, 
the closely related red colobus Colobus badius have 
been reported to occur at densities of over 300 
individual s/km 5 in KibaJe (Struhsaker. & Oates. 1975). 
while densities of over 300 individuals/km 2 have been 
reported for Colobus guereza on tl>e Kikuyu escarpment 
and over 500/km 2 in the Tanzanian highlands (Kingdom 
1971, Kingston. 1971; Estes. 1992) 
The dearth of colobus and other primates in the kaya 
forests may reflect a history of hunting by local peoples. 
These forests, protected under the National Monuments 
Act. could be used as future sites for translocation of 
colobus monkeys. However, illegal activities in these 
forests must be controlled first 
The colobus monkey population in Diani has certainly 
declined over the past 10 years and may be in danger of 
disappearing in this fast growing tourist resort area. Most 
of the monkeys are concentrated in an area a fraction of 
its former extent, and home ranges for each troop arc 
now only a few acres each. Forest loss and road kills are 
likely to be the main cause for the decline here, although 
use of colobus pelts in traditional dance has also been 
reported Other Kenyan populations of this primate face 
similar futures; the next ! 0 years will see development of 
forest land in Chalc and Shimoni while even protected 
kayas have been allocated for development. The 
densities of colobus in Diani forest demonstrate the 
importance of closed canopy forest for colobus monkeys 
Some monkeys survive in residential gardens where 
modified forest provides sufficient canopy cover for 
movement and feeding. These areas may play an 
important role of maintaining small isolated populations 
of these monkeys in the future. To 
prevent the Angolan colobus from 
blinking out in Diani. the Wakuluzu 
Trust aims to prevent further forest 
loss They are conducting 
conservation and public 
awareness activities such as 
buildi ng of rope bridges to provide 
safe road crossings for the 
monkeys and are working with 
residents of Diani to enrich the 
forest with colobus food plants 
The Shiniba Hills National Reserv e 
and Mvvnlunganje Forest Reserve 
currently represent the only 
significant forest areas that are 
safe for these monkeys in Kenya 
The future of tins subspecies of 
colobus in Africa depends also on 
its status in Tanzania One report 
of a precipitous decline in the 
number of colobus groups in the 
Selous between 1979 (Rogers. 
1980) and 1992 (Decker. 1994) from 34 groups to 9 
suggests a very serious situation (although Decker 
suggests that technique may be partly responsible for 
this discrepancy). A review of status of these monkeys 
in Tanzania and Kenya is badly needed in order to update 
the IUCN Status Survey and Conservation Action Plan 
of African Primates to allow for appropriate funding to 
effect their conservation. 
Acknowledgements 
This census is one of a series of surveys to be conducted 
on the Angolan colobus in Kenya The research is 
supported by Wakuluzu. Friends of the Colobus Trust 
The author is grateful to all the individuals who 
participated in the census, and to all the residents and 
hotels in Diani who permitted us to count monkeys on 
llicir properties. 
References 
Decker. B.S. (1994). Endangered primates in the Selous 
Game Reserv e and an imminent threat to their habitat 
Oner 23(3): 183-190. 
Estes. R.D (1992). Colobus monkeys In The behavior 
guide to African mammals California Press. 
Frankfurt Zoological Society (1989). The conservation 
Angolan black and white colobus curtesy of Wakuluzu, Friends of the 
Colobus, Trust 
