Boabeng-Fiema Monkey Sanctuary Research Articles

Effect of anthropogenic activities on carbon stocks in protected areas within Ghana's forest-Savannah transition zone

Tropical forests play a significant role in climate change by sequestering atmospheric carbon dioxide. However, deforestation and forest degradation adversely affect these forests’ carbon stocks. Reports indicate that anthropogenic activities have led to forest degradation and deforestation in Boabeng Fiema Monkey Sanctuary (BFMS) and Kogyae Strict Nature Reserve (KSNR). This study assessed the effects of these activities on the carbon stocks of BFMS and KSNR. Using satellite imagery, field measurements and allometric models, carbon stocks of the study area were assessed from 1992 to 2023. The assessment revealed significant losses attributed to anthropogenic activities, such as hunting, farming and charcoal burning. BFMS experienced a total loss of 40,236 Mg C, while KSNR lost 272,109 Mg C. The closed forests had the highest carbon stock amongst the different vegetation types, with soil representing the most significant carbon pool in the protected areas, revealing the influence of vegetation structure on carbon sequestration and the need for soil conservation. The substantial carbon sequestration potential observed in the different vegetation types of the study area indicates that the Forest-Savannah Transition Zone is a prospective area for climate change mitigation aligning with the Sustainable Development Goals (Goals 13 and 15) and the National Climate Change Policy of Ghana. These findings provide valuable insights for carbon trading and biodiversity conservation, emphasizing the potential of nature-based solutions in addressing global climate challenges.

Current populations of Colobus vellerosus (Geoffory, 1834) & Cercopithecus lowei (Thomas, 1923) and land-use, land cover changes in Boabeng-Fiema Monkey Sanctuary, Ghana

Background and Research aim: This study evaluated the density of two primate species Colobus vellerosus and Cercopithecus lowei and the change in land-use types in Boabeng-Fiema Monkey Sanctuary in Ghana, from 2007 to 2019. Method: Total counts of individual monkeys were done in all six patches of forest in the Sanctuary in 2019. Using Landsat imagery, land-cover maps of the study area were examined to evaluate the change that has occurred over a nine-year period between 2010 and 2019. Results: A total of 602 individuals of C. vellerosus were counted in 34 groups (0.58 group/ha). Group locations were: 15 at Boabeng (0.12 groups/ha), five at Fiema (0.08 group/ha), three at Bomini (0.09 group/ha), four at Busuyna (0.13 group/ha), three at Bonte (0.06 group/ha), and four at Akrudwa (0.11 group/ha). C. lowei was only encountered at Boabeng and Fiema, with a total of 351 individuals distributed in 26 groups. In 2010, forest covered a land area of 1,540.08 ha, and it was estimated to have increased to 2,643.12 ha in 2019. Farmlands covered 5,069.07 ha in 2010, and in 2019 were estimated to cover 4,155.03 ha. Built-up areas in 2010 covered an area of 433.89 ha, and in 2019 had declined to 244.89 ha. Conclusion: The monkey populations have increased and spread to occupy all patches in the Monkey Sanctuary. On LULCC, 72% increase, 18% reduction, and 44% reduction in forest cover, farmland and built-up areas were observed respectively. Implications for conservation: There is a blend of traditional and conventional conservation efforts contributing to the increase in primate population, the occupancy of previously ‘empty’ forest patches and change in areas of land-use types.

Non-Reproductive Sexual Behavior in Wild White-Thighed Colobus Monkeys (Colobus vellerosus).

Rare behaviors are often missing from published papers, hampering phylogenetic analyses. Here, we report, for the first time, masturbation and same-sex sexual behavior (SSB) in both male and female black-and-white colobus monkeys. We recorded these behaviors during 32months of observation (1573h of focal animal sampling) on Colobus vellerosus collected at the Boabeng-Fiema Monkey Sanctuary in Ghana. Males were observed masturbating and involved in SSB more than females. Subadult males were the age-sex class that engaged in both of these behaviors most often and a third of all SSB observed in young males occurred when they were forming an all-male band (AMB), which are temporally transient social groups in this species. Our data support that masturbation in males may be a sexual outlet for individuals that do not have a current sexual partner, while in females it may function in mate attraction by advertising receptivity. SSB may occur as an evolutionary byproduct but given the temporal clustering of observed events in males prior to AMB formation, our data best support the hypothesis that these behaviors facilitate male-male bonding (i.e., act as social glue). Within AMB's, males engage in coalitionary behavior to take over social groups containing females and strong bonds are important for success and later access to females, which could have selected for SSB in C. vellerosus.

Growing population of the critically endangered white-thighed colobus monkey (Colobus vellerosus) from forest fragments in Ghana

Abstract The population of critically endangered white-thighed colobus monkeys (Colobus vellerosus) at Boabeng-Fiema Monkey Sanctuary (BFMS) is possibly the only growing population of this species in West Africa. We assessed the current population status of C. vellerosus in BFMS and the surrounding fragments in Ghana. We undertook a complete count of the population in 2020, and this data was combined with previously conducted complete counts from 1990 to 2014. Results show that the total population growth rate of colobus monkeys at BFMS and the surrounding forest fragments was 353.9% between the 1990 and 2020 censuses (at a rate of 11.8% annually). In the BFMS alone, the total population growth rate was 252.3% between 1990 and 2020 (i.e., at a rate of 8.4% annually). The total population growth rate in the surrounding forest fragments was 97.0% between the first census year of 1997 and the 2020 census (i.e., at a rate of 4.2% annually). The mean group size in the BFMS was 16.7 individuals (SD = 4.0; range = 9–25), while that of the surrounding forest fragments was 14.4 individuals (SD = 4.6; range = 9–23). The overall mean group size was 16.1 individuals (SD = 4.3; range = 9–25). An approximate ratio of one adult male to three adult females (1:3.4) and one adult female to one immature (1:1.2) is an indication that the population of C. vellerosus still has the potential to increase further when new suitable forest fragments are explored in the future. C. vellerosus has the potential to increase further in population in small, suitable fragments if habitat destruction and settlement expansion are managed with primate conservation intentions.

Management of Sacred Groves and Customary Practices in Pursuit of Sustainable Forest Management

The goal of this investigation was to identify the customary practices on sacred groves and how they can help in achieving sustainable forest management in Ghana. The study examines forest management, deforestation, and sustainable forest management concepts. A case study of Boabeng Fiema Monkey Sanctuary and Malshegu Sacred Groves was explored. Interviews with community members were executed. Also, some secondary data on these two sacred groves were equally examined. The study found that taboos and other cultural beliefs were used to protect the sacred grooves with little government support. The study recommends that the state should make laws through the environmental protection agency and the forestry commission to support the cultural practices to achieve sustainable forest management.

Tourism as a Driver of Rural Socio-Economic Development: The Case of Boabeng-Fiema Monkey Sanctuary

Many countries especially developing ones like Ghana see tourism as a conduit for socio-economic development. This paper aims to examine stakeholders’ perceptions of the socio-economic effect of the Buabeng-Fiema Monkey Sanctuary. To achieve this aim, research was carried out into the role of tourism (a Monkey Sanctuary) in promoting rural socio-economic development in Ghana. The systematic sampling and purposive sampling methods were used to select 265 household heads and 11 key informants respectively from the Boabeng and Fiema communities. The questionnaire, interview guide, and observation were mainly used to collect data from respondents. The main finding reveals a community’s acceptance of tourism as having the potential to promote rural socio-economic development. However, this potential is challenged by the activities of the monkeys, destroying farm crops and properties coupled with an infrastructural deficit in the area. Implications are outlined for policymakers and the management of the wildlife sanctuary.

Dynamics of Ecotourism Benefits Distribution

ABSTRACT The purpose of this study was to explore the dynamics of ecotourism benefits distribution at Boabeng, which is found within the Boabeng-Fiema Monkey Sanctuary (BFMS) in Ghana. Data collection instruments included schedules, in-depth interview (IDI) and focus group discussion (FGD) guides. Findings from the study showed that there was disparity in the distribution of ecotourism benefits to the local households at Boabeng. Adverse impacts of ecotourism are making it difficult for households whose livelihood activities are located in the fringes of BFMS to engage in normal activities. The study has brought to the fore the complete personified livelihood experience within the individual households and ecotourism livelihoods in the Boabeng community. Again, this study argues that there is no significant relationship between socio-demographic characteristics of households and the distribution of ecotourism benefits. The study recommends that managers of the project in the community should consider the provision of social amenities using revenue from the project.

Influence of Visitors on the Time Budget, Ranging and Strata Use of Lowe's Monkey (Cercopithecus lowei) at Boabeng-Fiema Monkey Sanctuary, Ghana.

Wildlife tourism could be a conservation tool; however, it may disrupt the natural behaviors of wild animals. We examined how wildlife tourism affects Lowe's monkeys (Cercopithecus lowei) at the Boabeng-Fiema Monkey Sanctuary, central Ghana. We examined and compared the time budget, aggression patterns, home range size and strata use of two C. lowei groups-one with a high level of provisioning by visitors/tour guides (HP group) versus one with a low level of provisioning by visitors/tour guides (LP group). We found evidence that the HP group fed less and rested more than the LP group. The HP group significantly increased the time spent feeding and decreased their time resting, but no significant differences were recorded for moving or socializing either in the presence of small or big groups of visitors (i.e., 1-10 visitors or > 10 visitors). In the presence of one to ten visitors, the HP group monkeys increased the use of ground by 22.10% and decreased the use of medium and high tree strata by 15.43% and 11.6%, respectively. Agonistic behaviors (i.e., threat, chase, and attack) were three times higher in the HP group (e.g., open-jawed gaze gesture or head-bobbing). In the presence of visitors, aggression in the HP group increased from 12.81% to 30.18%. The home range size of the C. lowei HP group was smaller (4.68 ha) compared to the LP group (14.25 ha) (i.e., 50.56% difference). The LP group spent significantly less time socializing and more time moving. They fed more on fruits and insects. On average, the daily travel of LP group was 0.58 km more than the HP group (i.e., 22.80% difference), and the former group also spent significantly more time in the mid strata of the canopy. Our results showed that continued provisioning of the monkeys with human foods is detrimental to their natural behavior of the monkeys and could have negative long-term effects on the conservation efforts for the species.

Deforestation in forest-savannah transition zone of Ghana: Boabeng-Fiema monkey sanctuary

Forests provide many resources, ecosystem services and absorb carbon dioxide, which helps in climate regulation. In spite of the enormous benefits of forests, the issue of deforestation is still ongoing. There has been a continuous decline in forests globally and the forest area of Boabeng Fiema Monkey Sanctuary (BFMS) in Ghana is facing a similar threat. The aim of the study is to determine the different forest cover types and changes in the forest of BFMS. Satellite images for the years 1992, 1998, 2004, 2010, 2016 and 2018 were downloaded. Unsupervised and supervised classification were performed to determine the different forest cover types and remote sensing software was used to detect the changes in the forest cover. The forest cover was classified into six classes; closed forest, open forest, savannah woodland, savannah, farmlands and built-up area. Available data suggests that between 1992 and 2018, closed forest decreased by 242.19ha, open forest increased by 122.85 ha, savannah woodland increased by 7.47ha, savannah increased by 6.48 ha, farmland increased by 39.39ha and built-up area increased by 65.7ha. The changes in closed forest, open forest, farmland and built-up were all significant. Decreasing forest cover of BFMS is a threat to sustainable ecotourism since the forest serves as a habitat and food source to the monkeys. This research serves as guide to other researches aiming at determining forest cover changes in forest-savannah transition zones. In addition, the results have produced an inventory of the forest, which will help forest resource managers sustainably manage the forest.

Direct Stacked Investment Is a Flexible Reproductive Strategy for Female Colobus vellerosus

Most primates produce one offspring at a time but can overlap investment in consecutive offspring (stacked investment) depending on ecological and/or social conditions. “Direct stacked investment” occurs when a female conceives and gestates a new offspring while a previous infant is still suckling. We investigate direct stacked investment in Colobus vellerosus by determining if there is a period of overlap between nipple contact with a female’s first infant and gestation of her subsequent infant. We then investigate the effect of male group-membership and stability on stacked investment to test the hypothesis that stacking investment is a female strategy to avoid infanticide. We collected scan data to record when an infant was in nipple contact from 16 females in four groups of C. vellerosus, from May 2012 to May 2013 at Boabeng-Fiema Monkey Sanctuary in Ghana. We studied three group types, stable multimale, multifemale; unstable multimale, multifemale; and stable unimale, multifemale. Eight of our study females directly stacked investment. The frequency of direct stacked investment varied significantly among the group types. Stacked investment was due to earlier conception rather than delayed weaning, with females in stable multimale groups conceiving a subsequent infant earlier than those in unstable multimale groups. The timing of conception did not differ between stable unimale groups and either unstable or stable multimale groups. There was no difference in time to last nipple contact among group types. These results do not support the predictions of the infanticide avoidance hypothesis, but a larger sample size would help to test the hypothesis more comprehensively. Delayed conception by females in unstable groups may be infanticide avoidance, however, if it allows time for females to spread paternity certainty among males. Alternatively, females in unstable groups may be under stress or experience reduced feeding time due to frequent male–male agonistic interactions, both of which can suppress female ovulation. This study contributes to a growing body of research that explores flexibility in infant investment strategies, particularly in relation to external factors such as male group membership and stability.

Fringe community attitudes towards wildlife. The case of monkeys at Boabeng- Fiema monkey sanctuary, Ghana

Understanding community attitude towards wildlife sanctuaries plays a pivotal role in conservation. This study assessed the factors that influence community attitude towards the Boabeng-Fiema Monkey Sanctuary (BFMS) in Ghana. The study was carried out during the months of May and July, 2018 in four fringe communities around BFMS. Data was collected by random household interview (N = 102) through semi-structured questionnaires and key informant interview. The study revealed that attitude was largely influenced by benefits, concerns and culture. Concerns outweighed the benefits as such the local communities are somewhat positive towards the conservation of the monkeys and what it offers to the communities. Cultural valuation of the monkeys also influenced people’s interactions with wildlife. Fringe communities’ concerns and benefits are key to the management of protected areas and support for conservation at large. As such, measures should be put in place to ensure benefits outweigh the concerns of fringed communities. Keywords: Attitude, benefit, concern, fringe community, Ghana

Two Sides of the Same Coin: Formal and Informal Institutional Synergy in a Case Study of Wildlife Governance in Ghana

There has been the call to forge a synergistic relationship between local ecological knowledge and formal institutions in the governance of natural resources. How do informal institutions complement the efforts of formal state regulation of natural resources? How does this complementation foster a regularized human–wildlife interaction? Adopting an ethnographic design, this study assesses the role of institutional complementation in natural resource governance using the case of Boabeng–Fiema Monkey Sanctuary (BFMS) in Ghana, West Africa. We purposively selected 33 informants relevant to the BFMS governance process. The study observes that the synergy between formal and informal institutions strengthens wildlife protection in BFMS and the surrounding villages. The usefulness of informal rules is enhanced if appropriately complemented with a formal institutional arrangement. Over time, it becomes necessary for informal rules to grow in dynamism to depict the principles of collaboration, inclusivity, and benefit arrangements.

‘Complex crisis’ and the rise of collaborative natural resource governance: institutional trajectory of a wildlife governance experience in Ghana

Natural resource governance is underpinned by institutions which evolve ‘circumstantially’ over time. An attempt at understanding the contemporary institutions and governance structure of a resource requires an in-depth ethnographic enquiry. Adapting a four-phase institutional analysis framework, this study discusses the evolution and adaptation of wildlife governance structures and institutions using the unique experience of Boabeng–Fiema Monkey Sanctuary in Ghana. The study adopted a transdisciplinary research approach which was participatory and consultative. The key observations are that: wildlife institutions have gone through three main evolutionary phases, a pre-collaborative phase, which was exclusively underpinned by informal institutions; a critical juncture stage, where contextual challenges led to an adaptive response; the third and contemporary phase is a collaborative governance regime, where the erstwhile informal institutions have been complemented by formal state structures and institutions to synergistically enhance viability of the wildlife species. In spite of the problems posed to community members by the monkeys (wildlife), the study still observes a cordial human–wildlife relationship. Based on the study outcomes, we derive four key conclusions which have implications for institutionalism and natural resource governance.

Hormonal correlates of life history characteristics in wild female Colobus vellerosus.

Documenting primate life history characteristics is important because it provides information about traits that affect the timing and rate of reproduction in these long-lived species. This study describes the hormonal correlates of female reproductive events and quantifies for the first time key life history variables for Colobus vellerosus, using hormonal and observational data. This study also biologically validates that the reproductive events determined in the hormone profiles correspond to observed reproductive events for each female. We collected behavioural data on 18 females in our four study groups during 12months (May 2012-2013) at the Boabeng-Fiema Monkey Sanctuary, using 10-min continuous focal and ad libitum sampling. We concurrently collected faecal samples (n=1866) every 2-3days from these 18 females (prepubescent n=2, cycling n=2, lactating n=12, pregnant, n=7, and post-reproductive n=1) and extracted oestrogen (E2) and progesterone (P) metabolites in the field using solid-phase extraction cartridges. We created a hormone profile for each female by analyzing 1586 of our samples for E2 using radio-immuno assays, and P using enzyme-immunoassays at the Wisconsin National Primate Research Center. Mean ovarian cycle length was 24days±1 (n=2 cycles). Mean gestation length was 23weeks (range=21-25weeks, n=2 complete pregnancies). For females whose infants survived to nutritional independence, the mean inter-birth interval (IBI) was significantly longer than for females whose infants died prior to reaching nutritional independence (Mann-Whitney U Test; U=14.5, p=0.006; IBI surviving infants: 17.75 months, range=8-20.75 months, n=11 vs. IBI infant death: 11.89 months, range=8-18.5 months, n=9). The values for most life history traits reported in this study are similar to those documented in other similarly sized colobine species. Some values are on the lower end of the range for similarly sized colobines; C. vellerosus shows a cycle of 24days and gestation length of 5.75months vs. a range of 24-29days for cycle length and 5.25-7.5months for gestation length in other colobines. This may be due to C. vellerosus' smaller body size, or their limited access to higher quality food resources.

The influence of male takeovers on female dispersal in Colobus vellerosus.

Male takeovers affect male tenure, female mate choice and ultimately, individual reproductive success in group-living primates. In social systems with female philopatry and high male reproductive skew, male takeovers largely determine female mate choice, whereas in species with female dispersal, females have the option of deserting a new male. We focused on a species with facultative female dispersal to investigate which factors promote female desertion of males after takeover, using 15 cases (12 for which we have complete data on the takeover process and the female dispersal outcome). These cases took place in nine groups of Colobus vellerosus between 2001 and 2013 at the Boabeng-Fiema Monkey Sanctuary, Ghana. Quick takeovers were usually achieved by single adult males and were never followed by female dispersal. Slow takeovers involved several males, and these takeovers were regularly accompanied by female emigration. Infant attacks and infanticide by males occurred during both kinds of takeovers, but females with dependent offspring never dispersed, regardless of whether their infant was attacked or killed by the new male(s). Subadult females, who were not constrained by the presence of infants, dispersed more often after slow takeovers than after quick takeovers. Whether female dispersal post-takeover is an expression of female mate choice, or occurs to avoid the social upheaval surrounding slow takeovers, remains to be investigated. Am. J. Primatol. 79:e22436, 2017. © 2015 Wiley Periodicals, Inc.

Community-based ecotourism: Its socio-economic impacts at Boabeng-Fiema Monkey Sanctuary, Ghana

Abstract There is a lacuna in literature from Western Africa on how issue of participation influence socio-economic impacts at ecotourism destinations. This paper investigates the socio-economic impacts of ecotourism based on Boabeng- Fiema Monkey Sanctuary in Ghana. The paper is based on primary data generated from Boabeng and Fiema communities. Seventy mainly opened-ended questionnaires were administered face-to-face to purposively selected residents from the two communities, alongside, in-depth interviews with the management of the Sanctuary and focus group with purposively selected individuals from Boabeng and Fiema. The study reveals that the residents of the communities face burgeoning challenges such as shrinking livelihood options, inadequate involvement of community in the ecotourism, poor state of the visitor centre, inadequate government support and poor roads.

Female parity, maternal kinship, infant age and sex influence natal attraction and infant handling in a wild colobine (Colobus vellerosus).

Primate females often inspect, touch and groom others' infants (natal attraction) and they may hold and carry these infants in a manner resembling maternal care (infant handling). While natal attraction and infant handling occur in most wild colobines, little is known about the factors influencing the expression of these behaviors. We examined the effects of female parity, kinship, and dominance rank, as well as infant age and sex in wild Colobus vellerosus at Boabeng-Fiema Monkey Sanctuary, Ghana. We collected data via focal sampling of females in 2008 and 2009 (N = 61) and of infants in 2010 (N = 12). Accounting for the individuals who interacted with our focal subjects, this study includes 74 females and 66 infants in 8 groups. We recorded female agonistic interactions ad libitum to determine dominance ranks. We used partial pedigree information and genotypes at 17 short tandem repeat loci to determine kinship. We knew female parity, infant age and sex from demographic records. Nulliparous females showed more natal attraction and infant handling than parous females, which may suggest that interactions with infants are more adaptive for nulliparous females because they learn mothering skills through these behaviors. Compared to non-kin, maternal kin were more likely to handle infants. Maternal kin may be permitted greater access to infants because mothers are most familiar with them. Handlers may incur inclusive fitness benefits from infant handling. Dominance rank did not affect female interactions with infants. The youngest infants received the most natal attraction and infant handling, and male infants were handled more than female infants. The potential benefits of learning to mother and inclusive fitness, in combination with the relatively low costs of natal attraction and infant handling, may explain the high rates of these behaviors in many colobines.

The Effect of Forest Fragment Characteristics on Abundance of Colobus vellerosus in the Forest-Savanna Transition Zone of Ghana

We explore the factors influencing the abundance of Colobus vellerosus in 11 forest fragments [Boabeng-Fiema Monkey Sanctuary and 9 surrounding forest fragments (range: 3.2-190 ha)] in the forest-savanna transition zone of Ghana. We used a ‘complete' count for the colobus census in the fragments. We determined the fragment sizes using geographic information system methods and assessed forest fragment quality (tree species richness). Colobus individuals were absent from 4 forest fragments but present in 7 (densities of 0.13/ha-1.63/ha). We modelled colobus density using Poisson regression and selected models based on corrected Akaike information criterion model weights. Fragment size and tree species richness in the fragments were positively associated with colobus density, whereas isolation distance of the forest fragments (range: 20-5,632 m) was negatively associated with colobus density. Our analysis suggests that the isolation distance between the fragments and Boabeng does impede colobus movement. As the colobus populations in Boabeng and Fiema increase, some of the unoccupied fragments may become more attractive to dispersing monkeys. Management measures that aim at increasing tree species richness within fragments, while maintaining some large trees between fragments, might help to increase the occupancy of some of the fragments that currently have no permanent colobus groups.

Use of sleeping trees by ursine colobus monkeys (Colobus vellerosus) demonstrates the importance of nearby food

Examination of the characteristics and locations of sleeping sites helps to document the social and ecological pressures acting on animals. We investigated sleeping tree choice for four groups of Colobus vellerosus, an arboreal folivore, on 298 nights at the Boabeng-Fiema Monkey Sanctuary, Ghana using five non-mutually exclusive hypotheses: predation avoidance, access to food, range and resource defense, thermoregulation, and a null hypothesis of random selection. C. vellerosus utilized 31 tree species as sleeping sites and the species used differed per group depending on their availability. Groups used multiple sleeping sites and minimized their travel costs by selecting trees near feeding areas. The percentage that a food species was fed upon annually was correlated with the use of that species as a sleeping tree. Ninety percent of the sleeping trees were in a phenophase with colobus food items. Entire groups slept in non-food trees on only one night. These data strongly support the access to food hypothesis. Range and resource defense was also important to sleeping site choice. Groups slept in exclusively used areas of their home range more often than expected, but when other groups were spotted on the edge of the core area, focal groups approached the intruders, behaved aggressively, and slept close to them, seemingly to prevent an incursion into their core range. However, by sleeping high in the canopy, in large, emergent trees with dense foliage, positioning themselves away from the main trunk on medium-sized branches, and by showing low rates of site reuse, C. vellerosus also appeared to be avoiding predation in their sleeping site choices. Groups left their sleep sites later after cooler nights but did not show behavioral thermoregulation, such as huddling. This study suggests that access to food, range and resource defense, and predation avoidance were more important considerations in sleeping site selection than thermoregulation for ursine colobus.

Dispersal in male ursine colobus monkeys (Colobus vellerosus): influence of age, rank and contact with other groups on dispersal decisions

[Dispersal is male-biased in ursine colobus monkeys ( Colobus vellerosus ), although female dispersal also occurs (Teichroeb et al., 2009). Here we describe the process of male dispersal and its connection with between-group encounters (BGEs, N = 444) and male incursions (when males left their group and approached within 50 m of another group; N = 128) at the Boabeng-Fiema Monkey Sanctuary in central Ghana. Through BGEs and incursions, particularly those with non-aggressive interactions between individuals in different groups (BGEs, N = 17; incursions, N = 4), males could probably assess other groups for dispersal opportunities. There was a trend for males to perform incursions more frequently before emigrating voluntarily than involuntarily. Incursions were often performed towards the group that the male eventually transferred to. Incursions by alpha males were temporally shorter and more aggressive than those by non-alpha males. We suggest that non-alpha males used incursions to assess other groups for breeding or dispersal opportunities, whereas alpha males performed incursions mainly to convey information about their quality to neighbouring males and females. Male emigrations/disappearances (natal N = 20, secondary N = 43, unknown N = 9) and immigrations ( N = 62) were recorded for seven groups during ten years (2000– 2010). Alpha males always emigrated involuntarily. Parallel emigration and immigration occurred. Males often immigrated into groups with a more favourable adult male/adult female ratio and improved their rank, both of which likely increased their mating opportunities. The most fitting ultimate explanation for both natal and secondary male dispersal in this population was the intrasexual competition for mates hypothesis, as males of all ages appeared to emigrate to improve their reproductive opportunities., Dispersal is male-biased in ursine colobus monkeys (Colobus vellerosus), although female dispersal also occurs (Teichroeb et al., 2009). Here we describe the process of male dispersal and its connection with between-group encounters (BGEs, N = 444) and male incursions (when males left their group and approached within 50 m of another group; N = 128) at the Boabeng-Fiema Monkey Sanctuary in central Ghana. Through BGEs and incursions, particularly those with non-aggressive interactions between individuals in different groups (BGEs, N = 17; incursions, N = 4), males could probably assess other groups for dispersal opportunities. There was a trend for males to perform incursions more frequently before emigrating voluntarily than involuntarily. Incursions were often performed towards the group that the male eventually transferred to. Incursions by alpha males were temporally shorter and more aggressive than those by non-alpha males. We suggest that non-alpha males used incursions to assess other groups for breeding or dispersal opportunities, whereas alpha males performed incursions mainly to convey information about their quality to neighbouring males and females. Male emigrations/disappearances (natal N = 20, secondary N = 43, unknown N = 9) and immigrations (N = 62) were recorded for seven groups during ten years (2000– 2010). Alpha males always emigrated involuntarily. Parallel emigration and immigration occurred. Males often immigrated into groups with a more favourable adult male/adult female ratio and improved their rank, both of which likely increased their mating opportunities. The most fitting ultimate explanation for both natal and secondary male dispersal in this population was the intrasexual competition for mates hypothesis, as males of all ages appeared to emigrate to improve their reproductive opportunities.]