Determinants of pastoral migration decisions
The observation in the present study where male-headed households are more likely to migrate is in agreement with the traditional/cultural norms of most African pastoralists that allocate the responsibility to decide where to locate the household to the husband. These results are also consistent with the traditional model of household decision making reported by (Doss and McPeak (2005)), where husbands make decisions about herd management, in the best interest of the herd and family. However, the decision to migrate varies with ages of the household head, such that younger household heads are more likely to make migratory decisions compared to older heads. These results are in agreement with those of (Kabubo-Mariara (2002)), who reported that elderly people face less chances of migrating, implying they are less likely to migrate than their younger counterparts.
Results from the present study indicate that the household head's level of education and the size of the household are not a significant determinant of migration decision. It is probable that the causes of migration may be affecting all households, regardless of the level of education of the heads and household sizes. The observation that pastoralists owning large numbers of cattle are more likely to migrate than those with fewer numbers (Table 3) may be due to the faster depletion of resources (pastures and water) in a particular locality by the large numbers of animals, thus necessitating the need to migrate in search of resources elsewhere. Other reports indicate that households with smaller herds are better placed to temporarily send cattle to relatives/friends during times of crises so that they do not have to migrate (Kabubo-Mariara 2003). However, the negative coefficient in the ratio of sheep and goats to that of cattle (Table 3) suggests that pastoralists with more sheep and goats than cattle are less likely to migrate. This could be attributed to the better adaptation of sheep and goats to hash climatic conditions than cattle, hence less need for migration in search of range resources. In addition, small ruminants are not as fast as cattle in terms of mobility and take more time during migration, which is a limitation in case the herders are being pursued or are intending to move for long distances. As a result, it is easier and faster to migrate with cattle than with sheep and goats.
Pastoralists engaged in non-livestock income-generating activities are less likely to migrate (Table 3), probably because they keep fewer and a manageable number of livestock than those entirely relying on livestock production for their livelihood. Such diversification of income sources by pastoralists has been observed before. (Little et al. (2001)) reported that pastoralists engage in non-livestock activities not only to supplement consumption needs but also to buttress against risky shocks caused by climatic fluctuations, animal disease, market failures and insecurity. In Baringo, pastoralists engage in activities such as crop farming, honey harvesting, formal and informal employment. However, although cultivation is seen by some as a viable risk management strategy ((Campbell 1984; Smith 1998)), others view it as unsustainable and destructive option that even accentuates risk ((Hogg 1987; Hogg 1988)).
Generally, livestock migration by pastoralists has mainly been in search of range resources (water and pasture). However, another type of migration has emerged, where herders migrate to safer areas due to the intensity of cattle rustling/raiding or in fear of attack by rustlers (Table 3). Earlier, (Mkutu (2000)) noted that whenever droughts that cause scarcity of pasture and water, deplete a community's herd, they seek to replenish their stock through raiding. Thus, the insecurity associated with raiding leads to migration and the escape may involve long or short distances, depending on the information available about the level of insecurity and the availability of resources ((Young et al. 2005)). The route followed and the length of stay will depend on the intensity of the rustling. It is known that cattle rustling leads to loss of livestock, destruction of property, and injury and sometimes death of people, which are the main reasons that make herders migrate to safer places ((Hendrickson et al. 1996; Mkutu 2006)). In Kenya, cattle rustling has reached unprecedented proportions in the recent past. It has changed in nature, scale and dimension due to a number of factors, including the proliferation of small arms in the region, the commercialization of raiding, high unemployment in pastoral areas, frequent droughts and reduced respect for traditional conflict-solving mechanisms (CEWARN 2005).
Other than cattle rustling, there are other factors such as droughts and diseases that influence the decision to migrate. Unlike cattle rustling where some members of the community may be able to escape attacks by virtue of sheer luck, droughts and diseases affect the community entirely and in the same magnitude. Herders will therefore migrate to escape droughts and diseases due to fear of loss. (Little et al. (2001)) points out that to avoid loss of livestock through drought, pastoralists migrate in search of pastures and water. In other cases, the cycle of movement is determined not only by availability of pasture and water but also by the varying seasonal patterns of disease (Raikes 1981). The present observation where the type of land ownership is not a significant determinant of migration decisions may be attributed to most pastoralists in Baringo not having individual ownership of land but rather depending on communal lands. In such communal lands, available resources are exploited through migration from one locality to another.
The herder's perception of livestock migration is quite important in determining the decision to migrate. Those who perceive migration positively see it as a better means of survival for the livestock (Kabubo-Mariara 2003). The pastoralists in Baringo District, particularly the Pokot community, usually migrate in search of pasture and water during the dry season (January to March). Other factors may also influence the decision to migrate with livestock. Such factors include environmental degradation (Kabubo-Mariara 2005) and the desire to fallow the land to allow soil and vegetation to recover (Ahuja 1998).
Determinants of pastoral herd size
The observation that the gender of the household head influences herd size (Tables 4 and 5) may imply male-headed households are more likely to own larger herds of livestock than female-headed households, possibly because they shoulder more household responsibilities and hence the need for more livestock. Moreover, livestock plays several roles in smallholder systems such as dowry payments, status, initiation, ceremonial purposes and also as living "savings" (Ouma et al. 2003). In the traditional African context, it is the males who are expected to pay bride price (paid to the bride's family), initiation and other ceremonial occasions. Men also have a right to marry more than one wife, increasing the need for livestock to pay dowry. These expectations may be compelling men to engage in cattle rustling activities in order to replenish (after loss) or increase their herds (Mkutu 2000).
The mean number of cattle over household size is 4.88 (Table 2), with a median of 3.5. This herd size appears to be high and could be due to decreases in household size associated with the tendency towards monogamy, as well as improved livestock disease control services resulting in increase in animal numbers. Elderly household heads are more likely to keep larger herds than younger heads, probably because the elderly have a deep-rooted "cattle complex" culture where numbers of animals are often more important than the value they command. Also, the elderly, due to their age, have had the opportunity to accumulate livestock over time and, because of their attachment to their animals, have not disposed of them. On the other hand, the younger household heads are still in the process of accumulating their herds. (Livingstone (1977)) cited a number of contemporary adherents to the view of economic irrationality among the Pokot men (household heads), by equating wealth to animals owned and in the process accumulating a lot of animals, especially cattle.
Household heads with higher education level are more likely to keep fewer numbers of livestock than those with lower level of education or no education at all. This is probably because educated household heads are more likely to engage in other income-generating activities and as such may not be able to keep large numbers of animals that require more attention. Also, educated household heads are likely to have their children attending school, meaning they are faced with shortage of labour to look after livestock. Besides, educated household heads are likely to make use of market information and sell their animals for commercial purposes or for other reasons such as school fees.
The results of the present study that show the size of the household influencing herd size (Tables 4 and 5) suggest that large households are likely to own bigger herds of livestock than smaller households. Traditionally, large households indicate adequate availability of family labour necessary to look after large herd sizes. The large number of family members in a household may be a result of the head marrying many wives, and in order to pay the dowry for all the wives, he should have a large number of livestock. This is in agreement with the suggestions by (Ahuja (1998)) and (Kabubo-Mariara (2002)) that wealthy husbands owned large herds of livestock.
The negative correlation between non-livestock income and herd size suggests that pastoralists generating income from activities outside livestock rearing are likely to keep smaller herds of animals. This is perhaps an indication that herders may not invest their non-livestock income into increasing their herd size. It could also imply that livestock might be sold in order to invest in other non-livestock activities. As explained previously, pastoralists may reduce their herd for various reasons, including dowry payment, fear of losing animals to insecurity and other household needs such as food, school fees, medical treatment, etc.
The intensity and frequency of cattle rustling inversely affects the herd size of pastoralists, as it often leads to loss of livestock. This is an indication that herders that have lost livestock in previous attacks are more likely to keep smaller herds for fear of other attacks. Thus, the threats generated by the activities of cattle rustling influences decision making by pastoralists, a view supported by (Hendrickson et al. (1996)) and (Mkutu (2006)). Though not significantly influencing herd size, the coefficient for livestock lost to cattle rustlers suggest that it has far-reaching repercussions on herders' decision-making process. For example, if a herder decides to migrate in fear of attack or as a result of an attack by cattle rustlers, he/she might not be concerned about pasture and water availability or death of livestock due to diseases.
Droughts and diseases often lead to loss of livestock, thus reducing herd size. Nevertheless, unlike cattle rustling where once a raid has occurred there is constant threat of additional raids, successive droughts are typically separated by a return of rainy periods, even though brief at times, which helps to regenerate pasture and allow pastoralists time for the next period of stress (Hendrickson et al. 1996). The predominant communal land ownership in the study area enables equal access and utilization of available resources (e.g. pasture and water). Households are therefore not restricted to keeping a particular livestock herd size. Consequently, the type of land ownership is not a significant determinant of herd size.
The significant positive relationship between livestock inheritance and herd size noted in this study (Tables 4 and 5) suggests herders who have inherited livestock are likely to have larger herds than those who have not. In the culture of this group of pastoralists, a man's ownership of livestock starts at birth, where the father gives the child at least one female animal often symbolized by tying his navel cord to the animal soon after being born, and thereafter his herd builds up. Amongst the Somali pastoralist community, this practice is known as wahad (Guliye et al. 2007). Both dowry received and livestock bought by the pastoralists are not significant determinants of herd size. This is because as much as the pastoralists receive dowry when their daughters get married, they are also expected to pay the same as bride price when their male family members are getting married. Thus, although livestock is gained through dowry, it is also lost as bride price. Similarly, the sale of livestock for various household needs counteracts any increase in herd size resulting from purchase of animals.
Herders who perceive migration positively and migrate with their livestock are in a better position to access more pasture and water and avoid livestock losses through drought and diseases. Indeed, (Little et al. (2001)) note that herders who migrate with their herd, where mobility remains the key pastoral risk management strategy, have considerably fewer livestock loses during climatic disasters than their sedentary counterparts. Through migration, herders may also be able to avoid insecurities brought about by cattle rustling.