Introduction
To address the growing concern of pest problems related to yellow baboons (Papio cynocephalus) in the Diani area, the Colobus Trust carried out sixteen vasectomies on adult males during a two year period (January 1999 to December 2000). Fourteen individuals underwent the procedure successfully and were released two to three days post operatively while two males died under anaesthetic. All baboons vasectomised came from B2 troop.

The current appraisal in November 2003, conducted systematic searches of the four Diani baboon troops to identify individuals that were vasectomised. As males were marked with a V-shape in one ear during the operation, identification was made easier. The appraisal was done in conjunction with a baboon census.

Vasectomised Males Identified
Five vasectomised males were found. One in A troop and two in each troop – B1 and B2. C troop, the smallest troop in Diani, did not have any identifiable vasectomised males. The identified males are noted below, though for Mustafa of B1 and Kelele of B2, there is some doubt as to the certainty of their identification.

	Shujaa (A Troop) Characteristics: Tail missing end. Tail is blacker than tails of other males. Small scar between eyes. By 19th of October has torn lip (lower lip, left side) which had already begun to heal. Documented broken arm in December 1998. Long thin face. Behaviour: During the observations, Shujaa was aggressive with more dominant males. After several quiet weeks, he began regular aggressive encounters again.  Likely, Shujaa took the alpha position at the end of November.
		Kabungo (B1 Troop) Characteristics: Large male. Bulge on the tail end. Black mark on inside of left thigh. Two small white spots in the middle of the nose. Also two white larger spots at the side of nose. Behaviour: Appears to be a high ranking male, perhaps the alpha.
		Mustafa (B1 Troop) Characteristics: Large male though slightly smaller than Kabungo. Blacker hairs on the crown head. Head appears flatter than other males. When walking the tail is mostly in an 'S-shape'. Behaviour: A relaxed male perhaps second position in the hierarchy.
	Mau-Mau (B2 Troop) Characteristics: Torn lip, left upper canine visible. Scar on neck. Blondish hair. Large tail tip with bouncing tail when walking. Behaviour: Relaxed temperament, though looks around troop anxiously. Good social relationships with females.
	Kelele (B2 Troop) Characteristics: No tip on tail. Thin face with pronounced white marks on nose. Behaviour: Seems to wander; not always staying with the troop. When the B2 troop splits, he prefers subgroup B2a.

Discussion
The purpose of the vasectomy project had been to stabilize or reduce the baboon population in Diani. Population trends show a decline across all baboon troops in Diani in 2002. It appears that this is not reflective of the vasectomy project due to the length of time between the vasectomies conducted and the decline. In addition, the decline affects all troops, albeit some more than others, rather than just those troops where vasectomies were conducted, or where the males are currently found. Troop C, the troop with no vasectomised males, suffered a 55% decline in troop numbers.

Figure 1: Baboon populations by troop, 1998-2003

Possible explanations for the decline are the lower than average rainfall pattern (see Figure 2) and low tourist numbers (see Figure 3) in the preceding period to the decline. Please note that tourist bednight numbers had begun to increase after the low season of August 2002, but plummeted after the September 11th terrorist attack in America thus extending the time of low tourist numbers significantly. These two factors would have simultaneously reduced the food resources in wild areas as well as in garbage areas. As one would expect, the decline occurred in a time lag to the food resources being reduced. Due to scanty data, the time frame of the lag is difficult to assess. It will be interesting to note if the baboon population once again has a decline due to the terrorism threats of mid 2002 that resulted in a huge decrease in tourists due to British Airways banning flights to Kenya and specific travel bans on Kenya by America, UK, Germany and Australia.

These findings are preliminary only. Further data is required to corroborate the hypotheses.

Figure 2: Diani Rainfall in millimetres 1998-2003

Figure 3: Diani baboon population compared to tourist bednights by month2001-2003

Conclusion
Five vasectomised males were identified from the original fourteen males that successfully underwent the procedure.

Vasectomy is a humane method to control population growth. If carried out and managed properly, population could be controlled and sustained with genetic and other factors taken into account. However, this particular project, due to lack of funds, was unable to vasectomise all adult and subadult males in the four troops of Diani consistently. Unfortunately this made the project ineffective.

Though vasectomises are not an effective short term tool, they could be invaluable for managing populations in the long run if sufficient funds are available. Interesting sexual selection theories could also be tested if the vasectomy project was reinstituted.

Though the vasectomies did not appear to reduce the population, it is clear that the idea behind the project was innovative and it could be used not only in baboons but other species which require population management (i.e. elephants). Concentrating on male reproductive effort is a big step forward toward effective population management.

Appendix 1: Vasectomised males by date of surgery

Individual	Date of vasectomy	Estimated age at vasectomy	Features	Comments
Mshale	10th of  January 1999	?	White patches on both sides of nose, tail ends in point (no fur)	Died under anaesthetic
Duara	13th of January 1999	13.9 years	Large vertical scar on nose, map of Africa on right callosity + Britain on the left callosity	Mark in the top of left ear
Simba	10th  of March 1999	16 years	Several scars on face	No ear notch
Mzee	2nd of April 1999	13.4 years	Sagged lips, distinct bend in tail, closed left eye, thin pointed nose, limps on right hind leg	Notch in right ear
Mustafa	21st of April 1999	15.5 years	Limping on left arm, large scar on tail, vertical scar on right callosity	No ear notch
Kelele	29th of April 1999	14.4 years	Little scar under right eye, pronounced natural white marks on both sides of the nose, thin face	Notch on the bottom of the right ear
Kabungo	2nd of June 1999	15.5 years	Bulge on end of the tail, black mark on inside of left thigh	Notch in the middle of right ear
Panga	30th of June 1999	13.9 years	Gash on the left side of the face, horizontal scar at his nose	Notch in the middle, down left ear
Majestic	28th of October 1999	14.4 years	Walks in a bouncing manner, gash on left side of face	Notch in right ear
Mgonjwa	4th of November 1999	14.4 years	Piece of nose and upper lip missing	Notch in left ear
Kilema	3rd of April 2000	11.2 years	Two fingers missing on right hand, one blind eye	Notch in top of the right ear
Mau-Mau	5th of July 2000	12.3 years	Scar on neck, torn lip on left side, canine visible	Notch in top of right ear
Waria	17th of October 2000	13.3 years	Slim baboon with very grey hair and a sharp tip of tail	Notch in the top of left ear
Shujaa	9th of October 2000	8.5 years	Cut in the middle of nose, broken arm in December 1998, one canine missing	Notch in the right ear
Kaka	5th of December 2000	11.5 years	Slim and tall	Notch in the right ear
Mbwa	8th of December 2000	?	Dog like face, large callosities, very round in shape, white spots under both eyes	Died under anaesthetic

Note:
Age estimation was based on the following equation (probably Kummer, 1995):
0.537 (w – 0.108) w= weight

Some consideration should be made for errors in estimated age as the formula is based on estimations of wild baboons. Garbage feeders, such as the baboons found in Diani, are likely to be recorded heavier than wild feeding individuals of the same species. Discrepancies would make the individuals in the vasectomy program as recorded in Appendix 1, older than they are.