Blue monkey (Cercopithecus mitis stuhlmanni) predation on galagos

Two cases of predation on galagos by free-ranging blue monkeys (Cercopithecus mitis stuhlmanni) are described.C. mitis is only the second species of the genusCercopithecus known to prey on mammals. “Wadging,” the intermixing and chewing of leaves with meat, is reported for the first time in a primate other than the chimpanzee (Pan troglodytes). Meat-sharing was not observed inC. mitis.     

Distribution and conservation status of primates in Bioko island,Equatorial Guinea

Ten species of non-human primates are indigenous to Bioko; half of these are endangered and between five and eight are endemic subspecies. Recent data on their status and distribution have been lacking. In 1986, a ten-week survey of the island was carried out to determine the distribution and status of the primates and the natural vegetation, and to evaluate the effects of man on them. This paper presents the results of that survey, gives an update of conservation achievements since 1986, and highlights current concerns. Between 1974 and 1986 it is probable that numbers of all Bioko primates rose as a result of an increase in habitat and of reduced hunting. At the time of the survey there was considerably more natural, undisturbed, vegetation remaining in Bioko tran expected. Much of this vegetation occurs within two large blocks that are of outstanding importance to the conservation of species in tropical Africa, particularly of plants and primates.     

Assessment of the Diversity of African Primates

This account of the systematics of African primates is the consensus view of a group of authors who attended the Workshop of the IUCN/SSC Primate Specialist Group held at Orlando, Florida, in February 2000. We list all species and subspecies that we consider to be valid, together with a selected synonymy for all names that have been controversial in recent years or that have been considered to be valid by other authors in recent publications. For genera, species-groups or species, we tabulate and discuss different published systematic interpretations, with emphasis on more recent publications. We explain why we have adopted our taxonomic treatment and give particular attention to cases where more research is urgently required and in which systematic changes are most likely to be made. For all taxa, from suborder to subspecies, we provide English names.     

Demographic Variation Among Udzungwa Red Colobus in Relation to Gross Ecological and Sociological Parameters

We evaluated variation in group size and composition of Udzungwa red colobus (Procolobus gordonorum) in relation to gross-habitat and sociological parameters. The endangered species is endemic to the Udzungwa Mountains and nearby forests in the Kilombero Valley of south-central Tanzania. We counted 63 groups in 10 forests, ranging in altitude from 250 to 1,800 m. Group size ranged from 7 to 83 (x = 36.3) individuals and adult sex ratios (females/male) ranged from 1.5 to 7.3 (x = 3.5), excluding solitary individuals. Group size was influenced by several habitat parameters, including tree density, degree of deciduousness, and forest size. Groups were largest in large blocks of mature, moist, mixed evergreen and semideciduous forests, but group size is not correlated with altitude. Groups in a highly degraded forest appeared to have fission-fusion societies. The effect of habitat quality on age-sex composition of groups was most apparent in natality and less so in survivorship of adult females and juveniles. The number of adult males in groups accounted for 50% of the variance in group size and 34–39% of the variance in numbers of adult females in groups. Habitat quality affects natality more than demographic parameters do. Groups with a low proportion of adult females had greater juvenile survivorship, perhaps because of lower food competition between these two classes. We proffer hypotheses based on our study and previous intertaxonal comparisons to explain cause and effect relationships between habitat quality and demography. Finally, our study demonstrates the importance of large blocks of old-growth forest to the conservation of Udzungwa red colobus, and we make recommendations for conservation and research.     

The African golden cat Caracal aurata: Africa's least‐known felid

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Abundance of Diurnal Primates in Mwanihana Forest, Udzungwa Mountains, Tanzania

Many individual researchers have used line transect counts to estimate forest primate abundance. They have devoted less attention to the interpretation of line transect data obtained by several observers, as is often the case in long-term monitoring programs. We present primate relative abundance data that 5 observers collected over 6 yr (not continuous) along 4 different transects each 4 km long in the Mwanihana Forest, Udzungwa Mountains National Park, Tanzania. Total distance walked during transect repetitions is ca. 700 km. The species we saw most frequently was the endemic Udzungwa red colobus Procolobus gordonorum (mean 0.59 groups/km walked), followed by the Angolan black-and-white colobus Colobus angolensis (0.43 groups/km) and Sykes’s monkey Cercopithecus mitis (0.35 groups/km). We sighted the endemic Sanje mangabey Cercocebus galeritus sanjei and the yellow baboon Papio cynocephalus infrequently, the latter being confined to the deciduous forest parts of the transects. We analyzed sighting frequency by gross habitat type, transect, season, and observer. Interobserver differences in the relative abundance of each species were moderate and the few cases of significant variations were due to discordance of only 1 observer from the others. Estimated distances of primate group sightings differ significantly among observers, thus preventing us from deriving estimates of absolute density. Frequency distributions of distance-class intervals are not significantly different among observers, which may indicate gross interobserver consistency in the width of the area sampled. We conclude that unless consistency in data collection is checked, as we did for 2 observers who collected data simultaneously, potential interobserver differences remain an underlying source of variance in the results that cannot be separated from other sources of variance.     

Ecology of Physaloptera capensis (Nematoda : Spiruroidea) infecting the Springhare Pedetes capensis (Mammalia) in Botswana

Incidence and intensity of the stomach nematode Physaloptera capensis in relation to the age, sex, reproductive status, physical condition, density and habitat of its host, the Springhare, were investigated in the Republic of Botswana (August 1971-August 1973). All data indicate that this nematode is a benign parasite of the Springhare. Infections were not randomly distributed within the Springhare population. Mean number of worms per Springhare was 83 and 34% of all Springhares were parasitized. Adults, females and lactating females showed significantly heavier infections than juveniles, males and non-lactating females, respectively. Infection was directly associated with the amount of grass cover in the Springhares' habitat but independent of the density and physical condition of Springhares. Possible causes of differences in rates of infection among Springhares of different age/reproductive classes and from populations of different density are mentioned. It is suggested that numbers of P. capensis may be regulated mainly by density-independent environmental factors operating upon rates of transmission.     

Primate population dynamics over 32.9 years at Ngogo, Kibale National Park, Uganda

We present census data for eight primate species spanning 32.9 years along the same transect at Ngogo, Kibale National Park, Uganda, demonstrating major changes in the composition of the primate community. Correlated with an estimated decline of ～89% in the red colobus population was an increase in encounter rates with chimpanzee parties. Our data, along with the unusually high rates of predation by chimpanzees on red colobus at Ngogo and the fact that the chimpanzee community at Ngogo is the largest ever recorded, support the conclusion that the red colobus decline was caused primarily by chimpanzee predation. This seems to be the first documented case of predation by one nonhuman primate causing the population decline in another. We evaluated disease and interspecific competition as other possible causes of the red colobus decline, but judged them to be relatively insignificant compared with predation by chimpanzees. Notable changes in encounter rates with other primate species may have resulted from forest expansion. Those for mangabeys, redtails, and black and white colobus increased significantly. Encounter rates increased for l'Hoest's monkeys too, but the increased sightings may have been an artifact of increased habituation. Sightings of blue monkey and baboon groups declined. There was no significant change in encounter rates for all species combined. The Ngogo primate community seemed to be in a nonequilibrium state, changing from one dominated by two species, a folivore (red colobus) and a frugivorous omnivore (redtails), to one dominated by three species of frugivorous omnivores (redtails, mangabeys, and chimpanzees). This study demonstrates the importance of long-term monitoring in understanding population dynamics and the role of intrinsic variables in shaping the species composition of a community.