The Barbados vervet monkey (Cercopithecus aethiops sabaeus): Changes in population size and crop damage, 1980-1994

We investigated changes in population site and crop damage for the vervet monkey (Cercopithecus aethiops sabaeus) in Barbados over the period 1980-1994. In both 1980 and 1994, we obtained data primarily via a survey of farmers islandwide to obtain estimates of group size and number of groups on agricultural land. We assessed the farmers' estimates independently for reliability by counting number of groups and group size on a subsample of fawns. We surveyed approximately 20% of the total land area in Barbados and extrapolated the results to the whole island. The estimate of population size of monkeys in 1994 is 4% greater than for 1980, but the difference is not statistically significant. This suggests that, despite the removal of over 10,000 vervets via humane trapping and through hunting over the 14-year period, population size has remained the same. Over the same time period, the percentage of crops damaged by vervets was reported by farmers to have increased almost 30%. The increase in crop damage relative to the increase in vervet abundance may best be explained by a decrease in the availability of crops to vervets, since substantial amounts of agricultural land were taken out of crop production between 1980 and 1994.