Ranging behaviour and its relation to diet selection in Tana River Red colobus (Colobus badius rufomitratus)

Ranging behaviour of a group of Red colobus monkeys, Colobus badius rufomitratus, on the Tana River, Kenya, is described. The main study group had a mean day journey of 603 in and an annual range area of 9 ha (measured in 0.25 ha quadrats). Relationships between ranging patterns and diet selection are sought on both spatial and temporal dimensions. Differential use of the annual range is related to the distribution of major food species, while the diversity of monthly ranging patterns is inversely related to the availability of young growth in the canopy. These findings lead to a discussion of why range areas at the Tana are much smaller than those reported from rain-forest sites.     

Seminomadic Ranging in a Population of Black Colobus (Colobus satanas) in Gabon and its Ecological Correlates

We observed ranging patterns in a black colobus population in the Forêt des Abeilles, Central Gabon. We compared the results with those for two other populations (Lopé Reserve in Central Gabon, Douala-Edéa in coastal Cameroun) in order to estimate the extent of specific variability in population structure and ranging behavior and to identify ecological factors influencing interpopulation differences. The mean number of monkeys in a group is 17, and all groups had a multimale structure. Home ranges were large, and the fact that they continued to increase with increasing number of observations indicated that the monkeys did not frequently resample their habitat. Ranging patterns varied according to the staple food consumed: distances travelled daily increased with increasing seed intake and decreased with increasing leaf intake. The ranging patterns of groups of Colobus satanas are seminomadic. Up to 6 or 7 groups shared the same space, and two group ranges could overlap by as much as 65–75%. Comparisons with the two populations previously studied showed that group size and group structure are broadly similar. At all three sites, black colobus were mainly seed eaters and ate large amounts of leaves in the season of fruit shortage. In the Forêt des Abeilles, however, group home ranges were much larger than at other sites, and this population had the lowest density. This is correlated with vegetation composition and with harshness of the main dry season. This colobus population appears limited by both recurring food shortage in the dry season and episodic periods of seed shortage resulting from irregular fruiting of the dominant family Caesalpiniaceae. Their seminomadic ranging would constitute the least costly strategy to cope with the low carrying capacity of their habitat.     

Ecology of the Zanzibar Red Colobus Monkey: Demographic Variability and Habitat Stability

We examined the Zanzibar red colobus' (Procolobus kirkii) social structure and population dynamics in relation to the density, diversity and dispersion of food resources in ground-water forest and agricultural land, which we characterized in terms of red colobus food species density, diversity, basal area and dispersion. We used transect sampling and group follows to describe population dynamics and social systems. Two agricultural areas, SJF Shamba and Pete Village, had higher densities and more uniformly dispersed red colobus food tree species than those of the ground-water forest. Red colobus at these two sites had greater population densities and natality, and smaller home ranges than red colobus in the ground-water forest. However, these findings apply to a very small area of agricultural land (approximately 18 ha) that is contiguous with an area of the forest reserve having a high density of red colobus. It is not representative of agricultural areas elsewhere on Zanzibar which support much lower densities or no red colobus. Although agricultural areas contiguous with the forest reserve had high densities of red colobus, they appear to be very unstable. Within the agricultural areas, we observed higher intergroup variation in group size and composition, study groups that decreased dramatically in size and disappeared from the study site, significantly lower levels of juvenile recruitment, and red colobus food trees that exhibited definite signs of overbrowsing. This apparent instability in the subpopulation of red colobus utilizing agricultural systems probably reflects the lower basal area of food trees and the greater fragmentation of suitable habitat and floristic dynamics due to human activities in these areas. A fusion-fission social system occurred only in the ground-water forest subpopulation, which we hypothesize to be due to highly clumped food resources.     

Test of the ecological-constraints model on ursine colobus monkeys (Colobus vellerosus) in Ghana

For group-living mammals, the ecological-constraints model predicts that within-group feeding competition will increase as group size increases, necessitating more daily travel to find food and thereby constraining group size. It provides a useful tool for detecting scramble competition any time it is difficult to determine whether or not food is limiting. We tested the ecological-constraints model on highly folivorous ursine colobus monkeys (Colobus vellerosus) at the Boabeng-Fiema Monkey Sanctuary in Ghana. Three differently sized groups were followed for 13 months and two others were followed for 6 months each in 2004-2005 using focal-animal sampling and ranging scans; ecological plots and phenology surveys were used to determine home-range quality and food availability. There was relatively little difference in home-range quality, monthly food availability, diet, adult female ingestion rates, and rate of travel within food patches between the groups. However, home-range size, day-range length, and percent of time spent feeding all increased with group size. We performed a single large test of the ecological-constraints model by combining several separate Spearman correlations, each testing different predictions under the model, using Fisher's log-likelihood method. It showed that the ecological-constraints model was supported in this study; scramble competition in this population is manifesting in increased ranging and time spent feeding. How costly this increased energy expenditure is for individuals in larger groups remains to be determined.     

Dominance style in female guerezas (Colobus guereza Rüppell 1835)

Socioecological models assume that quality and distribution of food ultimately determine female social relationships: a high quality diet and clumped food distribution should result in the establishment of a hierarchy with stable rank relations which is supported by empirical studies on frugivorous cercopithecines. By contrast, folivorous species with their low quality diet and dispersed food distribution should have egalitarian social relationships but empirical data are very rare. This study on female guerezas of a zoo group aimed to test the models in a colobine species and the results largely agreed with the predictions of the models: facial expressions, vocalizations, and gestures were not used for signalling dominance or subordination. Unritualized aggressions occurred frequently but were of low intensity, and interventions by third parties were never observed. Aggressions were exchanged bidirectionally and this was true also for food stealing and retreats. All this indicated the lack of established rank relations. Allogrooming was distributed rather equally and showed no kin bias. All these features characterize egalitarian social relationships and, hence, support the socioecological models.     

Movement patterns of a group of free-ranging mountain gorillas (Gorilla gorilla beringei) and their relation to food availability

Relationships between the movement patterns of free-ranging mountain gorillas (Gorilla gorilla beringei) and the abundance and distribution of foods in their home range were examined. During an 18-month field study, the ranging of one group of G. gorilla beringei was recorded on a 250 × 250 m grid system, from which measurements of frequency and duration of use, travel rate, and rate of revisitation of each quadrangle by the group were derived. Food items were sampled in selected quadrangles throughout the home range and various measures of food abundance, frequency and diversity were calculated. Analyses based on both spatial and temporal variation in food availability give supporting evidence for the prediction that mountain gorilla ranging patterns are influenced by the distribution and abundance of foods. Quality of food appears to be an important factor, as shown in analyses of yearly patterns and monthly changes in ranging. The gorillas studied spent more time in the higher quality areas of their home range, responded to a correlate of decreasing food abundance by increasing their rate of travel and area used, and revisited regions more frequently when the renewal rate of foods was clearly greater. Each of their foraging tactics can be explained as serving to increase the efficiency of harvesting foods.     

Incisor microwear and diet in three species of Colobus

Examination of incisor microwear in three species of Colobus revealed that the predominantly folivorous C. badius more closely resembles C. satanas, a seed predator/folivore, than C. guereza, another predominantly folivorous species. This demonstrates that species of the same broad dietary category can have very different patterns of incisor microwear, indicative of differences in food procurement behavior and/or the physical properties of dietary items for some portion of the diet. Conversely, species of different categories can have microwear patterns that, superficially at least, are quite similar. The dissimilarity in incisor microwear between C. badius and C. guereza is mirrored to a certain extent in molar microwear, although the differences are not nearly so great on the molars. The differences between C. badius and C. guereza may involve different food items in the major, folivorous portions of their diets, or they may relate to differences in the very minor fruit and bark components. The similar microwear patterns of C. badius and C. satanas demonstrate that incisor microwear by itself is unreliable for assigning fossil species to broad dietary categories. Incisor microwear can be used to infer finer dietary distinctions in fossil species for which dietary category has been determined by other means.     

Ranging behaviour and habitat preference of a wild marmoset group, Callithrix humeralifer (Callitrichidae, Primates)

The ranging behaviour of a group of marmosets ( Callithrix humeralifer ) in seasonal Amazonian rain forest was studied during one year. Range sizes (monthly and daily), day range lengths and patterns of range use are examined for correlations with feeding behaviour and the distribution of three forest types within the marmoset's range. Seasonal differences in ranging are associated with changes in the abundance and distribution of plant food sources. The marmosets ranged more widely and used more sources of a greater diversity of plant food species, which were distributed over a wider area, in the wet season than in the dry season. In the dry season, they ranged over a smaller area and, although they used fewer sources of a reduced diversity of plant species overall, they exploited a larger number of sources of the five highest ranked plant species in the diet. Throughout the year, they showed a preference for disturbed primary forest, characterized by dense understoreys and abundant second growth patches. Reasons for this preference are discussed, taking into account their use of fruits of typical pioneer species (particularly in the dry season), insect prey abundance, sleeping site availability and defence against predators.     

Biogeographical patterns in the diet of an opportunistic predator: the red fox Vulpes vulpes in the Iberian Peninsula

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Constraints on Group Size in Red Colobus and Red-tailed Guenons: Examining the Generality of the Ecological Constraints Model

The ecological constraints model proposes that an increase in group size will increase intragroup feeding competition and thereby constrain group size. Although this model has received wide acceptance, tests of it are based only on a few studies of species that have similar ecological requirements and social organizations, and there are reasons to question the widespread acceptance of the assumptions underpinning it. Via a 2-year study, we explored determinants of group size in species that feed on markedly different types of foods: the folivorous red colobus (Procolobus pennantii) and the frugivorous/insectivorous red-tailed guenon (Cercopithecus ascanius). We established 4 study sites approximately 15 km apart in Kibale National Park, Uganda, to examine the relationship between average group size and food availability. In both species, we quantified interdemic variation in diet, density of food trees, rate of travel, and group size. Red colobus at all sites relied heavily on leaf resources (75.5%–86.9%), but fruit (6.4%–13.9%) and flowers (2.0%–13.9%) were important in some populations. In general, red-tailed guenons fed on fruit (35.7%–59.7%), insects (14.5%–17.6%), and young leaves (12.2%–32.8%), but the amount of time allocated to these foods varied among sites. Average monthly density of trees bearing food items ranged among sites from 45 to 79 trees/ha for red colobus and from 19.6 to 67.3 trees/ha for red-tailed guenons. For both species, rate of travel was similar among sites, with one exception for red colobus. Average red colobus group size varied among sites from 14 to 40 (28 groups counted). Red-tailed guenon group size varied among sites from 11 to 24 (16 groups counted). As predicted by the ecological constraints model, group size increased with food tree density across sites for both species.     

Effects of Seasonal Folivory and Frugivory on Ranging Patterns in <Emphasis Type="Italic">Rhinopithecus roxellana</Emphasis>

The distribution of food resources in time and space may affect the diet, ranging pattern, and social organization of primates. We studied variation in ranging patterns in a group of Sichuan snub-nosed monkeys (Rhinopithecus roxellana) over winter and summer in response to variation in their diet in the Qingmuchuan Nature Reserve, China. There was a clear diet shift from highly folivorous in winter to highly frugivorous in summer. The home range was 8.09 km² in summer and 7.43 km² in winter, calculated via the 95% kernel method. Corresponding to the diet shift, the focal group traveled significantly longer distances in summer (mean 1020 ± 69 m/d) than in winter (mean 676 ± 53 m/d); the daily range was also significantly greater in summer (mean 0.27 ± 0.02 km²/d) than in winter (mean 0.21 ± 0.01 km²/d). There was no significant variation in home range size between winter and summer, and the monkeys did not use geographically distinct ranges in summer and winter. However, overlap in the actual activity area and core range between winter and summer was only 0.13 km², representing 4.4% of the summer core area and 5.3% of the winter core area. Differences were apparent between summer and winter ranging patterns: In summer, the group traveled repeatedly and uninterruptedly across its home range and made 3 circles of movement along a fixed route in 31 d; in winter, the activity area was composed of 3 disconnected patches, and the focal group stayed in each patch for an average of 8 successive days without traveling among patches. Winter range use was concentrated on mixed evergreen and deciduous forest patches where leaves and fruits were available, whereas the summer range pattern correlates significantly positively with the distribution of giant dogwood (Cornus controversa) fruits. Thus it appears that the diet shift of Sichuan snub-nosed monkeys between winter and summer caused the monkeys to use their home range in different ways, supporting the hypothesis that food resources determine primate ranging patterns.     

Composition and variability of mountain gorilla diets in the Central Virungas

Data are presented here on the feeding ecology of wild mountain gorillas (Gorilla gorilla beringei) which were observed for approximately 2,400 hours over a 17-month period in the Parc National des Volcans, Rwanda. Aspects of the relationship between the composition, diversity, and temporal consistency of the gorillas' diet and spatial and temporal variability in food distribution patterns are described. Mountain gorillas are folivores that show considerable specialization on plant parts, species and families. This pattern is facilitated by the general richness of their habitat. Their environment is heterogeneous, and spatial variability in food distribution is more pronounced than temporal variability. The gorillas rely almost completely on perennially available foliage of herbs and vines. Their diet varies little in association with seasonal factors but varies markedly in space in association with variability in the vegetational composition of the habitat. Individuals in the main study group shared basically similar patterns of food choice. Different groups also shared a similar general pattern, although there were differences in detail that apparently resulted largely from vegetational contrasts between home ranges. The gorillas' behavioral responses to environmental complexity lend general support to recent ideas concerning the evolution of their social system.     

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.     

Intergroup Relationships in Western Black-and-White Colobus, <Emphasis Type="Italic">Colobus polykomos polykomos</Emphasis>

We investigated patterns of intergroup relationships in western black-and-white colobus, Colobus polykomos, in Taï National Park, Côte d'Ivoire, between 1993 and 1999. They live in one-male multifemale units, and demonstrate male dispersal and occasional dispersal by females. Solitary males and all-male bands are absent or very rare. Our aim was to investigate the function of female and male aggression during intergroup interactions. The species is particularly interesting because, in contrast to predictions from socioecological models, female aggression occurs during intergroup interactions in combination with female dispersal. Home ranges of neighboring groups overlapped considerably and groups lacked an area of exclusive access. Intergroup interactions occurred once every 6.6 observation days. Encounters were either peaceful (12%), or involved displays and threats (25%) or chases and fights (63%). Females interacted in 74% and males in 98% of aggressive intergroup encounters. We found little to no indication that male and female aggression correlated with the presence of food, importance of a location, or presence of infants or receptive females. However, females were more often aggressive during the months when the group depended strongly on seeds from Pentaclethra macrophylla. We also observed forays by males to other groups. Forays occurred on average once every 20 observation days. In 75% of the forays, the intruding male chased members of the target group. In 25% of the forays 1–3 females joined their male but females never attacked the target group. Our main study group was the target of such forays significantly more often when young infants were present in the group than when not. We conclude that female aggression between groups was related to food procurement and that male forays might be related to infanticide.     

Scramble Competition Among <Emphasis Type="Italic">Colobus vellerosus</Emphasis> at Boabeng-Fiema,Ghana

We investigated the occurrence of scramble competition among Colobus vellerosus at Boabeng-Fiema, Ghana. If scramble competition had an impact on feeding efficiency among females, we expected a positive relationship between group size and the proportion of time spent feeding, day journey length, or home range size assuming resource availability is similar among the groups compared. We collected focal data on the feeding behavior of adult females and males over 11 mo (September 2000–August 2001) on 2 study groups: WW (n = 31–33 individuals) and B (n = 8–16 individuals). We also collected ranging data on group movements at half-hour intervals. The large group (WW1) had a significantly longer day journey length than the small group (B1), and females in the large group spent a significantly greater proportion of time feeding in the wet season, a period of low food availability, which suggests it may be a bottleneck period when food resources are scarce and Colobus vellerosus is close to being energy limited. The proximity data suggested females may be able to reduce or adjust for competition by having fewer neighbors when they feed and by spreading out when in a larger group. However, we found no relationship between home range size and group size or that females spent a greater proportion of time feeding than adult males did. Our results highlight the need to factor in differences in food availability when investigating scramble competition. Though equivocal, our results suggest scramble competition occurs among Colobus vellerosus, leading us to suggest there was a match with the potential competitive regime, i.e., food distribution.     

Non‐territorial Macaques Can Range Like Territorial Gibbons When Partially Provisioned With Food

Human food supplementation can affect components of animal socioecology by altering the abundance and distribution of available food. We studied the effect of food supplementation by comparing the ranging patterns and intergroup interactions of two groups of northern pigtailed macaques (Macaca leonina), a non‐territorial primate species. One group was partially reliant on food provisioning, whereas the other group foraged wild food. We also compared the macaques’ movement with that of a group of white‐handed gibbons (Hylobates lar), a territorial species inhabiting the same site. Home range, core area, and daily path lengths were significantly smaller for the semi‐provisioned group than for the wild‐feeding group. In contrast to wild‐feeding macaques, supplemented macaques showed higher fidelity to home range, core area, and particularly to the region where human food was most accessible and abundant. The relationship of daily path length and home range indicated a low defendability index for wild‐feeding macaques; the higher index for the semi‐provisioned group was consistent with the territorial pattern found in gibbons. Semi‐provisioned macaques showed further traits of territoriality with aggression during intergroup encounters. These findings indicate that human modification of food availability can significantly affect movement patterns and intergroup competition in macaques. The observed ranging dynamics related to food provisioning may decrease the efficiency of macaques as seed dispersers and increase predation on their home range, and thus have important consequences for plant regeneration and animal diversity.     

Comparison of habitat quality and diet of Colobus vellerosus in forest fragments in Ghana

The forest fragments surrounding the Boabeng-Fiema Monkey Sanctuary (BFMS) in central Ghana shelter small populations of Colobus vellerosus. Little is known about these populations or the ability of the fragments to support them, despite the fact that these fragments represent potentially important habitat for the colobus in this region. We compared the diet of three groups of C. vellerosus in the fragments to two groups in BFMS. We also examined the differences in plant species composition and food abundance among fragments. The study took place from June to November 2003. Dietary data were collected using scan sampling. Plant species composition and food abundance were evaluated using tree plots and large tree surveys. As in BFMS groups, leaves constituted the highest proportion of the diet of fragment groups, yet the colobus in fragments fed on more lianas than did those in BFMS. Over 50% of all species observed eaten by colobus in the fragments were not consumed in BFMS groups during the same season. Food abundance was similar between fragments and BFMS, although species composition differed. There was no relationship between the density of colobus and the density of food trees or percentage of food species, suggesting that other factors may be influencing the number of colobus present. This study highlights the broad dietary range of C. vellerosus, which may be a factor allowing its survival in these fragments.     

Lion-tailed macaques (Macaca silenus) in a disturbed forest fragment: Activity patterns and time budget

We describe the activity patterns and time budget of a feral group of lion-tailed macaques that were confined to a disturbed forest fragment of 65 ha and compare the results with those obtained for groups in protected forests. The degraded nature of the study site was reflected in low tree densities, low specific diversity, gaps in the girth distribution of trees, and frequent disturbance by humans. The study group of 43 subjects was twice as large as lion-tailed macaque groups in protected habitats. They spent the most time ranging (34.0%), followed by foraging (23.7%), feeding (17.9%), resting (16.0%), and other activities such as social interactions (8.4%). Monthly variations are significant for all activity categories except ranging. Times spent resting and foraging are negatively correlated (r = −0.5) and show significant seasonal differences. Foraging time was highest from September to November, when key food sources such asCullenia andArtocarpus were absent or marginally available. The study group spent most time (40.4%) at canopy levels between 21 and 30 m. They spent more time each day ranging than resting or feeding and more time terrestrially compared with groups in protected forests. Large group size, poor habitat quality, and seasonal variation in food availability were the major variables affecting their time budget, and these variables accounted for differences from the time budgets of groups in protected forests.     

圈养赤斑羚夏季日食量及表观消化率的探讨

<正>野生动物营养学是野生动物生态学和管理学的重要组成部分,是了解野生和圈养野生动物种群生存和繁殖的核心内容之一(Robbins,1983)。动物采食是一个复杂的、动态的、生物和非生物因素相互作用和相互影响的过程(Van Soest,1994),同时受动物自身、环境和饲料等多种因素的影响,有时还存在互作(NRC,1996)。采食量决定营养物质的摄入量,决定着动物能够从环境中获得营养物     

Ranging behavior and foraging ecology of lowland woolly monkeys (Lagothrix lagotricha poeppigii) in Yasuní National Park,Ecuador

In a year-long study, I investigated the ranging behavior of lowland woolly monkeys (Lagothrix lagotricha poeppigii) in a terra firma rainforest in Yasuní National Park, Ecuador, and examined the relationship between ranging, diet, food availability, and food patch use for this population. In Yasuní the total home range sizes for two social groups were 124 and 108 ha, which are much smaller than has been reported previously for Lagothrix elsewhere in its geographic distribution. The mean yearly day range estimates for these same groups were 1,792 m and 1,878 m, which are well within the range of variation previously reported. Ranging behavior was not correlated with the current habitat-wide abundance of ripe fruit, which comprises 76.3% of the yearly diet for this population, but was associated with one measure of likely insect prey abundance and with the availability of immature fruits, a minimal part of the diet. Specifically, one study group moved significantly greater distances during months of high likely insect prey abundance and when immature fruits were abundant. The second study group also traveled farther when likely insect prey abundance was high and when immature fruits were abundant, although the latter relationship only approached significance. This group also devoted significantly more of its daily activity budget to travel during these times. These results indicate that variation in ripe fruit abundance makes no meaningful contribution to explaining variation in ranging behavior for this population of woolly monkeys. Instead, the results raise the possibility that some aspects of the ranging behavior of frugivorous primates may be related to the availability of alternative food sources, such as animal prey, or to monitoring the phenological status of important fruit trees, rather than simply reflecting the degree of intragroup feeding competition.