Comparative studies on vertical separation,foraging behavior and traveling mode of saddle-backed tamarins (Saguinus fuscicollis) and red-chested moustached tamarins (Saguinus labiatus) in Northern Bolivia

The author made comparative studies on the ecology of saddle-backed tamarins (Saguinus fuscicollis) and red-chested moustached tamarins (S. labiatus) on the upper Amazon in northern Bolivia. The unit group of both species of monkeys was a family group composed of two to seven individuals, but they often formed polyspecific associations comprising one such family group each. However, both species preferred different layers of forest for foraging insects and traveling.S. fuscicollis mainly utilized the lower layer of the forest and foraged large-sized insects lurking in tree hollows, whereasS. labiatus mainly utilized the middle layer of the forest and foraged small-sized animals on branches. These differences were more clearly noticeable in secondary forest than in primary forest.     

Tamarin polyspecific associations: Forest utilization and stability of mixed-species groups

Niche separation is likely to play a key role in the formation of mixed-species groups. Saddle-backed tamarins (Saguinus fuscicollis) were studied at three sites with different primate communities in northern Bolivia: (1) with red-bellied tamarins,S. labiatus; (2) with emperor tamarins,S. imperator; and (3) without a congeneric species. The degree of association is higher betweenS. labiatus andS. fuscicollis than betweenS. imperator andS. fuscicollis and is related to differences in forest utilization between associating pairs. Niche separation is found to be greater betweenS. labiatus andS. fuscicollis than betweenS. fuscicollis andS. imperator. The mean height and habitat utilization ofS. fuscicollis does not differ greatly across the three sites, nor does the height of tamarins in and out of association. It is concluded that combined with differences in body size and dietary overlap, vertical segregation plays an important role in tamarin polyspecific associations (increasing the potential of both foraging and anti-predatory benefits) and that this is not a consequence of vertical displacement ofS. fuscicollis by its dominant congeners.     

Seasonal patterns of diet and ranging in two species of tamarin monkeys: Stability versus variability

From June through December, data were collected on the diet and ranging patterns of moustached (Saguinus mystax) and saddle-back (Saguinus fuscicollis) tamarin monkeys in the Amazon Basin of northeastern Peru. During this 7-month period, insects and nonleguminous fruits accounted for 83% of tamarin feeding and foraging time. Despite marked seasonal variation in rainfall and forest productivity, patterns of habitat utilization, day range, dietary diversity, resource exploitation, and activity budget remained relatively stable throughout the year. Moustached and saddle-back tamarins appear to solve problems of food acquisition and exploit patchily distributed feeding sites using a relatively limited set of foraging patterns. In general, these primates concentrate their daily feeding efforts on several trees from a small number of target plant species. These feeding sites are uncommon, produce only a small amount of ripe fruit each day, and are characterized by a high degree of intraspecific fruiting and flowering synchrony. Trees of the same species are frequently visited in succession, and individual feeding sites are revisited several times over the course of 1–2 weeks. This type of foraging pattern occurred during both dry and wet seasons and when exploiting fruit, nectar, legume, and exudate resources. Seasonal variation in the percentage of feeding and foraging time devoted to insectivory was also limited. In this investigation, there was no consistent evidence that temporal changes in overall forest fruit production had a major impact on the feeding, foraging, or ranging behavior of either tamarin species.     

Home Range Size and Habitat Use in the Black Lion Tamarin (Leontopithecus chrysopygus)

The black lion tamarin (Leontopithecus chrysopygus) is a threatened species due to past destruction of its natural habitat, thus knowledge of its home range size and use is essential in planning for its conservation. I studied one group for 4 months in the Morro do Diabo State Park, in São Paulo State, Brazil. I estimated the home range of the group to be 64 and 127 ha via the quadrat and convex polygon methods, respectively, while a composite method yielded an estimate of 106 ha. They ate insects most frequently (38% of scans), a resource which was distributed throughout their home range. Fruit was the second major resource, but when it was not available, they ate more gum. The exploitation of fruits was associated with dryland forest, while gum-feeding occurred mainly in swamp forest. The study group used a transition zone between dryland and swamp forest most frequently, and all of their sleeping trees were located there. Although the vegetation reached 15–20 m, the group spent most of the time (55%) in the upper understory, between 4 and 8 m high. The study group revealed more specific habitat needs than thought previously, suggesting that the current population may be smaller than estimated.     

Role of spatial memory in primate foraging patterns: Saguinus mystax and Saguinus fuscicollis

From field data collected in the Amazon Basin of northeastern Peru, I present evidence that moustached (Saguinus mystax) and saddle-back (Saguinus fuscicollis) tamarins maintain detailed knowledge of the distribution and location of many tree species in their home range. During the wet season months of October through December 1984, fruits and exudates from 20 tree species and over 150 individual trees accounted for 75% of plant feeding time. These trees exhibited a patchy distribution; mean nearest-neighbor distances between trees of the same species averaged 148 meters. Moustached and saddle-back tamarins visited an average of 13 trees per day, concentrating their feeding efforts on 4–11 individual trees from a small number of target species. In 70% of all cases the nearest tree of a given species was selected as the next feeding site. Movement between these sites was characterized by relatively straight-line travel. It is argued that S. mystax and S. fuscicollis offset the patchiness component of the fruit and exudate part of their diet through goal-directed foraging and an ability to compare accurately the distances and directions from their present location to a large number of potential feeding trees.     

Modeling monkeys: A comparison of computer-generated and naturally occurring foraging patterns in two species of neotropical primates

We present a series of computer-generated foraging models (random movement, olfactory navigation, and spatial memory) designed to examine the manner in which sensory cues and cognitive skills might be used by rainforest monkeys to locate patchily distributed feeding sites. These simulations are compared with data collected in the Amazon Basin of northeastern Peru on the foraging patterns of two species of neotropical primates, the moustached tamarin monkey (Saguinus mystax) and the saddle-back tamarin monkey (Saguinus fuscicollis). The results indicate that, although tamarins may rely on olfactory cues to locate nearby feeding sites, their foraging patterns are better explained by an ability to maintain a detailed spatial map of the location and distribution of hundreds of feeding trees in their home range. There is evidence that such informationis retained for a period of at least several weeks and is used to minimize the distance traveled between widely scattered feeding sites. The use of computer simulations provides a powerful research tool for generating predictive models regarding the role of memory and sensory cues in animal foraging patterns.     

Habitat Use and Ranging Behavior of <Emphasis Type="Italic">Callimico goeldii</Emphasis>

We studied the diet, habitat use, and ranging behavior of 1 group of Callimico goeldii (callimicos) over 12 mo in northwestern Bolivia. The group’s diet was comprised of fungi (39%), fruits (31%), arthropods (14%), exudates (14%), and other matter (2%). Callimicos concentrated their ranging activities in secondary forest (50%), primary forest with dense understory (30%), and bamboo (17%) habitats. The group’s total home range was 114 ha; on average they used 38.4 ha/ mo and had a day range of 925 m. Monthly average day ranges—but not monthly home ranges—increased as frugivory declined, suggesting that subjects foraged on fungi and exudates by rechecking resources within a core area, making their day ranges longer than during months when they concentrated on fruit resources. The callimicos formed polyspecific associations with tamarins (Saguinus labiatus and S. fuscicollis) during 81% of observations. Day ranges increased in months with higher association rates which appears to result from the callimicos using a broader set of habitats when with tamarins than when alone. The ranging pattern of callimicos appears to be influenced primarily by 3 factors: their seasonal shift in diet requires that they forage in a variety of habitats across the year; their depletion of resources causes them to shift their core area over time; and their lack of territorial behavior eliminates the need to patrol boundaries as part of their daily movement. As a result, callimicos differ from many other callitrichids in their low ratio of day range length to home range size.     

Home range structure and inter-group competition for land of Japanese macaques in evergreen and deciduous forests

The per capita home range area of Japanese macaques,Macaca fuscata, is significantly smaller in evergreen forest than in deciduous forest, though a corresponding difference in food resource utilization patterns has never been described. The present study compared the home range utilization pattern of Japanese macaques living in two habitats: the Yakushima population inhabits an evergreen forest, while the Kinkazan population inhabits a deciduous forest. We found that in the Yakushima population, (1) food density was higher; (2) inter-feeding bout sites distance was shorter; (3) daily travel distance was shorter; (4) home range size was smaller; and (5) the unit value of the main home range was higher, than in the Kinkazan population. Yakushima groups utilized a small home range area intensively, compared to Kinkazan groups. We also found that a Yakushima group shared 24% of its main home range with neighboring groups, though a Kinkazan group shared only 10% with other groups. It is supposed that food distribution affects daily ranging pattern, and ultimately the social relationships between groups in Japanese macaques.     

Habitat selection by capercaillie in summer and autumn: Is bilberry important?

The use of habitat by female and male adult capercaillie Tetrao urogallus during summer and autumn was studied by comparing the distribution of radio locations of birds with the availability of habitat at forest stand, home range and landscape level in an area of the Bavarian Alps, Germany. Capercaillie preferred forests with structural features typical of their main distribution range, the boreal forest: they selected large patches of old forest with moderate canopy cover of about 50%, and a well developed field layer with high proportions of bilberry Vaccinium myrtillus. Hens selected both home ranges and sites within home ranges in old forest. Ranges selected by cocks did not differ from availability in the study area, but they preferred old forest within their ranges. The size of home ranges was negatively related to bilberry cover both in hens and cocks. The distribution of bilberry also determined habitat use by capercaillie at the landscape scale. The study demonstrated that bilberry is the major determinant of the selection of habitat by capercaillie in landscapes with sparse and fragmentary cover of ericaceous shrubs, such as central Europe.     

Habitat and diet of young grouse broods: resource partitioning between Capercaillie (Tetrao urogallus) and Black Grouse (Tetrao tetrix) in boreal forests

We compared habitat use and diets of young Capercaillie and Black Grouse broods in a boreal forest in southeast Norway. We used pointing dogs to search for broods (N = 83) in mature “natural” forest types and examined the crop content of 66 chicks 1–9 weeks old. We also measured the abundance of insects in the habitats where broods were found. Although overlapping substantially in both habitat and diets, there were notable differences: Capercaillie broods were more frequently recorded in bilberry-dominated forest types, whereas Black Grouse preferentially used pine bog forest, a more open habitat with little bilberry. Capercaillie chicks ate proportionally more insects, particularly lepidopteran larvae, and insects dominated their diet for a longer period of time (until age 28–29 days) than in Black Grouse (14–15 days). After reaching their peaks, the quantity of insects in the crops declined rapidly especially in Capercaillie, and in one of 2 years this occurred at a time when insects, including larvae, were still abundant in the habitats. Among plant foods, both species ate large amounts of Bilberry (Vaccinium myrtillus) and Bog Whortleberry (V. uliginosum). The main difference between species was a large proportion of both over-wintered and new, not yet ripe, berries of Cranberry (Oxycoccus quadripetalus) in Black Grouse, and a higher proportion of the forb Melampyrum sylvaticum in Capercaillie. The difference in diets reflected their differential use of habitats; the Vaccinium-preferred habitats of Capercaillie were richer in insects, particularly larvae, than the pine bog habitat preferred by Black Grouse. Because insects, especially larvae, comprised a larger proportion of the diet of Capercaillie chicks and chicks of this species need more food to sustain their rapid growth, Capercaillie is likely to be more sensitive to variation in insect food than Black Grouse. Also, by reducing the abundance of bilberry, the main host plant of larvae chick food, clearcutting forestry has negative effects on the brood habitat quality of both species.     

Effect of Resting Patterns of Tamarins (<Emphasis Type="BoldItalic">Saguinus fuscicollis</Emphasis> and <Emphasis Type="BoldItalic">Saguinus mystax</Emphasis>) on the Spatial Distribution of Seeds and Seedling Recruitment

The spatial distributions of dispersed seeds have important evolutionary consequences for plants. Repeated defecations in sites frequently used by seed dispersers can result in high seed concentrations. We observed the resting behavior of a mixed-species group of tamarins in Peru and recorded the occurrence of seed dispersal (over 8 mo) and seed fate (over 11–22 mo) to determine whether the location and use of resting sites influenced the spatial distribution of dispersed seeds and seedlings. The tamarins rested mostly on trees (Saguinus fuscicollis: 60.6%, S. mystax: 89.2%) and dead trunks (S. fuscicollis: 24.4%) and used 61% of their resting sites repeatedly. During both the dry and wet seasons, tamarins dispersed significantly more seeds within resting areas (0.00662 and 0.00424 seeds/m², respectively) than outside them (0.00141 and 0.00181 seeds/m²). Seed survival and seedling recruitment did not differ significantly between resting and other areas, resulting in a higher seedling concentration around the resting sites. Seed density did not increase with the duration or the frequency of use of the resting sites but did increase when we pooled the seasonal resting sites together in 50 m × 50 m quadrats, ultimately causing a clumped distribution of dispersed seeds. The use of resting sites in secondary forest, particularly during the dry season, allows the creation of seedling recruitment centers for species coming from the primary forest. Our findings show that tamarin resting behavior affects the spatial distribution of dispersed seeds and seedlings, and their resting sites play an important role in plant diversity maintenance and facilitate forest regeneration in degraded areas.     

Habitat Utilization of Three Sympatric Cheirogaleid Lemur Species in a Littoral Rain Forest of Southeastern Madagascar

I compared the habitat utilization in 3 sympatric species of Cheirogaleidae (Microcebus murinus [81 g], Cheirogaleus medius [183 g] and Cheirogaleus major [362 g]) in a littoral rain forest in southeastern Madagascar during 3 rainy seasons. Females of promiscuous Microcebus murinus had small home ranges and the males had large overlapping home ranges. Home ranges of family groups of monogamous Cheirogaleus medius and C. major overlapped extensively. Home ranges of all 3 species overlapped completely in the study area but home range sizes differed among species and correlate positively with body masses. Male Microcebus murinus slept in open vegetation (79%) and alone (71%), whereas female M. murinus and family group members of Cheirogaleus spp. preferred communal sleeping in tree holes. There are significant interspecific differences in the choice of sleeping sites: smaller lemurs chose smaller trees and used more sleeping sites than larger lemurs did. Species also differed significantly in the vertical dimension of forest utilization: Cheirogaleus major used the upper part of the trees, C. medius used the middle parts, and Microcebus murinus used the understory during nocturnal activities. The 3 species differed mainly in vertical habitat utilization and showed vertical stratification.     

Foraging behavior of a tamarin group (Saguinus fuscicollis weddelli) and interactions with marmosets (Callithrix emiliae)

We present data on aspects of the behavioral ecology of a free- ranging group of Saguinus fuscicollis weddelliat a site in Brazilian Amazonia where a second callitrichid, Callithrix emiliae,is syntopic. Diet, activity patterns, and ranging behavior are broadly similar to those of S. fuscicollisfrom sites in Bolivia, Brazil, and Perú, though significant seasonal changes include an extreme and atypical form of ranging behavior in which they foraged in central-place fashion around a source of exudate—Parkia pendula. S. f. weddelliwas active at relatively low levels in the forest both in absolute terms and relative to C.emiliae, which appears to be an important factor in their niche partitioning. Association between the two species appeared to be less systematic overall than those observed between S. fuscicollisand congeners at other sites, though this may be partly a result of observation conditions. During the period of central-place foraging, the two species exhibited a high degree of association. Other characteristics of the behavior of S. f. weddelliat the study site include the frequent use of tree holes as sleeping sites.     

Home range and habitat use by the sable<Emphasis Type="Italic"> Martes zibellina brachyura</Emphasis> in a Japanese cool-temperate mixed forest

Home range and habitat use of the sable Martes zibellina brachyura were studied in a cool-temperate mixed forest in northernmost Japan. In both sexes, some sables showed a wide range of migration without establishing home ranges and the others had home ranges of 0.50–1.78 km² (mean: 1.12±SD 0.495 km², n =6) which were not significantly correlated with body weight or age. The analysis of canine tooth annuli revealed that the maximum age was 5.5 years. The home ranges of some sables overlapped so extensively that the home ranges and even the core areas did not appear exclusive to other sables. We determined resting sites and foraging routes in snow in winter. Comparison of vegetation at the resting sites and foraging routes with habitat availability suggested that the sables preferred resting in dense-tree forests with many tree species and debris probably in order to avoid predators (red foxes) and strong wind and foraging in forests of climax succession which are usually rich in their prey such as voles and mice.     

Biology of <Emphasis Type="Italic">Cheirogaleus major</Emphasis> in a Littoral Rain Forest in Southeast Madagascar

Greater dwarf lemurs (Cheirogaleus major) are small nocturnal primates from the rain forests of eastern Madagascar. I investigated a population of Cheirogaleus major in a littoral rain forest of Southeast Madagascar during 2 rainy seasons to supplement the sparse information available for the species. I collected data on morphology, group composition, sleeping behavior, home range, and social organization via mark/recapture, radio telemetry, and focal individual observations. I identified 2 presumed family groups, and my data from radiotracking revealed a monogamous social organization. In each group, I found an adult pair and its presumed offspring sharing home ranges and sleeping sites together. I also observed gregarious behavior of group members during their nocturnal activity. I found no difference in body measurements between sexes, but body mass and tail circumference increased significantly from November to February, indicating a fatting period before hibernating.     

Bird and insect pollinators differ in specialization and potential pollination services along disturbance and resource gradients

Combined studies of the communities and interaction networks of bird and insect pollinators are rare, especially along environmental gradients. Here, we determined how disturbance by fire and variation in sugar resources shape pollinator communities and interactions between plants and their pollinating insects and birds. We recorded insect and bird visits to 21 Protea species across 21 study sites and for 2 years in Fynbos ecosystems in the Western Cape, South Africa. We recorded morphological traits of all pollinator species (41 insect and nine bird species). For each site, we obtained estimates of the time since the last fire (range: 2–25 calendar years) and the Protea nectar sugar amount per hectare (range: 74–62 000 g/ha). We tested how post-fire age and sugar amount influence the total interaction frequency, species richness and functional diversity of pollinator communities, as well as pollinator specialization (the effective number of plant partners) and potential pollination services (pollination service index) of insects and birds. We found little variation in the total interaction frequency, species richness and functional diversity of insect and bird pollinator communities, but insect species richness increased with post-fire age. Pollinator specialization and potential pollination services of insects and birds varied differently along the environmental gradients. Bird pollinators visited fewer Protea species at sites with high sugar amount, while there was no such trend for insects. Potential pollination services of insect pollinators to Protea species decreased with increasing post-fire age and resource amounts, whereas potential pollination services of birds remained constant along the environmental gradients. Despite little changes in pollinator communities, our analyses reveal that insect and bird pollinators differ in their specialization on Protea species and show distinct responses to disturbance and resource gradients. Our comparative study of bird and insect pollinators demonstrates that birds may be able to provide more stable pollination services than insects.     

Modelling oldfield species richness in a mountain area

Seed predation by rodents affects plant population dynamics and it mayrespond to changes in vegetation structure at forest edges. This studyinvestigates the magnitude and direction of a potential edge effect intemperatedeciduous forests, and it seeks possible explanations based on predatorabundance and vegetation structure. The study was conducted at twelve forestedges in northern Switzerland; in six sites all shrubs at the forest edge wereremoved, whereas the other sites maintained a structurally rich shrub layer. Ineach site three transects were laid out from the edge towards the forestinterior. In six plots along these transects (at 1, 3, 6, 12, 25, 50m) we studied seed removal from experimental dishes, rodentabundance in live-traps and four characteristics of the vegetation structure.For both woody seed species (Prunus avium,Viburnum lantana) predation was significantly higher nearthe forest edge in the structurally rich sites; in the other sites no suchgradient was found. Selectively accessible dishes revealed that rodents werethemain predators, whereas predation by insects or molluscs was not observed.Abundance of rodents (Apodemus flavicollis, A.sylvaticus, Clethrionomys glareolus) washighestunder dense shrubs close to the forest edge. In the structurally rich sitesthere was a clear gradient of decreasing shrub cover from the edge towards theforest interior; a weaker gradient was observed in the structurally poor sites.We conclude that high shrub cover near the forest edge is the main determinantfor edge effects in seed predation, and edges without a shrub belt show no sucheffect.     

Orangutan diet,range, and activity at Tanjung Puting,Central Borneo

Previously, wild orangutan feeding and ranging behaviors have been described only from populations in hilly or mountainous regions. The Tanjung Puting study focuses on an orangutan population in a swampy lowland area near sea level. Tanjung Puting also differs from other areas in the virtual absence of large figs, which are significant orangutan food sources elsewhere. During a 4-year period and 6804 hr of observation, focal orangutans were recorded in 11,338 foraging bouts accounting for 3805 hr. Composition and phenology of the forest habitat were documented. The orangutans were predominantly frugivorous, with fruit-eating accounting for 61% of the foraging time. However, the overall variety in their diet was remarkable; 317 different food types have been identified, including fungus, insects, and honey. Orang-utans were strongly opportunistic foragers, with the composition of their diet varying markedly from month to month. During most months orangutans fed on a complex mix of fruit, leaves, bark, insects, and small vines. During some months fruit was not the major component of the diet. All orangutans foraged in both the dry-ground mixed dipterocarp forest and the peatswamp forest habitats found in their ranges. Adult males and females utilized different proportions of certain resources in their diets. Prime adult males also ranged further per day and spent more time on the ground than prime adult females. At Tanjung Puting contact with other orangutans usually increased a focal orangutan’s day length, day range, and amount of time spent moving. This suggests that foraging alone maximized each orangutan’s foraging returns by minimizing the day range traveled. Orangutan solitariness is the result of a large body size and of a predominantly frugivorous and opportunistic diet.     

An ecological comparison of two sympatric primates:Saguinus fuscicollis andCallicebus moloch of Amazonian Peru

The ecologies of two sympatric primates,Saguinus fuscicollis andCallicebus moloch, were compared during a four-month field study in southeastern Peru in order to examine the mechanisms by which these primate frugivores minimize competition for food and space.Saguinus fuscicollis andCallicebus moloch were found to differ dramatically both in diet and in use of the shared habitat. Specifically, tamarins and titis showed very little overlap in their choices of food plants or animal foods and they used distinctive foraging styles, exploiting very different parts of the habitat for animal prey. Significant interspecific differences were found in the use of particular support structures and strata within the forest, and in the density of vegetation preferred. These results suggest that resource competition between saddle-backed tamarins and dusky titis is minimal, a fact that could account for the high frequency of free association between the two species and the benign nature of these interspecific contacts.     

On the ecology and behavior ofCebus albifrons in eastern Colombia: I. Ecology

A-503 contact-hr study of a 35-member group ofCebus albifrons was conducted in eastern Colombia in 1977 and 1978. The group had a female: male socionomic sex ratio of 2.5:1 and used a home range of 110–120 ha which overlapped the home range of another group ofC. albifrons about 20–30 ha. The animals spent about 80% of their foraging time eating plant material and about 20% of their foraging time eating animal materials. A birth peak at the end of the dry season extending into the wet season was indicated by data available. Attempted predation was recorded by the mustelidEira barbara and the black-and-white hawk-eagleSpizastur melanoleucus. Some association was observed with the red howler monkeyAlouatta seniculus. The group at times spent more than half the day foraging and traveling on the ground, exhibiting a level of terrestriality not reported for other New World primates.