Dominic Wormell

Bio: Dominic Wormell is an academic researcher from Durrell Wildlife Conservation Trust. The author has contributed to research in topics: Population & Callitrichidae. The author has an hindex of 6, co-authored 14 publications receiving 121 citations.

Population densities of primates in a Brazilian Atlantic forest

Abstract: The Brazilian Atlantic rain forest ecosystem, perhaps the most threatened in the Neotropics and now reduced to 7% or less of its original extent, contains the highest density of endangered Neotropical primate taxa [1]. We report population density estimates for three species endemic to the region: Geoffroy’s marmoset (Callithrix geoffroyi), the northern masked titi (Callicebus personatus) and the robust tufted capuchin (Cebus apella robustus), all considered vulnerable.

Individual, social, and environmental factors affecting salivary and fecal cortisol levels in captive pied tamarins (Saguinus bicolor)

Abstract: Pied tamarins (Saguinus bicolor) are endangered New World primates, and in captivity appear to be very susceptible to stress. We measured cortisol in 214 saliva samples from 36 tamarins and in 227 fecal samples from 27 tamarins, and investigated the effects of age, sex, pregnancy, rearing history, social status, weight, group composition, and enclosure type using generalized linear mixed models. There was no effect of age on either fecal or salivary cortisol levels. Female pied tamarins in late pregnancy had higher fecal cortisol levels than those in early pregnancy, or nonpregnant females, but there was no effect of pregnancy on salivary cortisol. Females had higher salivary cortisol levels than males, but there was no effect of rearing history. However, for fecal cortisol, there was an interaction between sex and rearing history. Hand-reared tamarins overall had higher fecal cortisol levels, but while male parent-reared tamarins had higher levels than females who were parent-reared, the reverse was true for hand-reared individuals. There was a trend towards lower fecal cortisol levels in subordinate individuals, but no effect of status on salivary cortisol. Fecal but not salivary cortisol levels declined with increasing weight. We found little effect of group composition on cortisol levels in either saliva or feces, suggesting that as long as tamarins are housed socially, the nature of the group is of less importance. However, animals in off-show enclosures had higher salivary and fecal cortisol levels than individuals housed on-show. We suggest that large on-show enclosures with permanent access to off-exhibit areas may compensate for the effects of visitor disturbance, and a larger number of tamarins of the same species housed close together may explain the higher cortisol levels found in tamarins living in off-show accommodation, but further research is needed.

Managing free-ranging callitrichids in zoos

Abstract: This paper describes the management techniques developed over 20 years of experience with free-ranging groups of callitrichids at Durrell Wildlife Park (formerly Jersey Zoo), UK, with an additional 12 years of information from Zurich Zoo, Switzerland. Seventeen groups of eight different species have been released in woodland areas at Durrell, and two groups at Zurich. Release periods ranged from 2 weeks to 14 years. The evolution of release protocols is described, along with brief descriptions of problems that have occurred. The advantages and problems of maintaining callitrichids in free-ranging environments are discussed.

Social Experience of Captive Livingstone’s Fruit Bats (Pteropus livingstonii)

Abstract: Social network analysis has been highlighted as a powerful tool to enhance the evidence-based management of captive-housed species through its ability to quantify the social experience of individuals. We apply this technique to explore the social structure and social roles of 50 Livingstone’s fruit bats (Pteropus livingstonii) housed at Jersey Zoo, Channel Islands, through the observation of associative, affiliative, and aggressive interactions over two data collection periods. We implement binomial mixture modelling and characteristic-based assortment quantification to describe the complexity and organisation of social networks, as well as a multiple regression quadratic assignment procedural (MRQAP) test to analyse the relationship between network types. We examine the effects of individual characteristics (i.e., sex, age, and dominance rank) on social role by fitting models to explain the magnitude of node metrics. Additionally, we utilize a quadratic assignment procedural (QAP) test to assess the temporal stability of social roles over two seasons. Our results indicate that P. livingstonii display a non-random network structure. Observed social networks are positively assorted by age, as well as dominance rank. The frequency of association between individuals correlates with a higher frequency of behavioural interactions, both affiliative and aggressive. Individual social roles remain consistent over ten months. We recommend that, to improve welfare and captive breeding success, relationships between individuals of similar ages and dominance levels should be allowed to persist in this group where possible, and separating individuals that interact frequently in an affiliative context should be avoided.

The international conservation programme for the White-footed tamarin Saguinus leucopus in Colombia

Abstract: The White-footed or Silvery brown tamarin Saguinus leucopus is an endemic Colombian species, threatened by the pet trade and loss of habitat, and for which protection is minimal. Local authorities confiscate about one animal every week, placing them in rescue centres and zoos where there are many husbandry problems. An international conservation programme was established in 2005, currently coordinated by Beauval Zoo in France and locally by Asociacion Colombiana de Parques Zoologicos y Acuarios (ACOPAZOA). The programme is a partnership between a consortium of 21 European zoos, ACOPAZOA, local organizations (including nine Colombian zoos), central and regional conservation public authorities, non-governmental organizations (especially the Wildlife Conservation Society), Colombian universities and researchers. The project combines ex situ in-country reproduction, education and research, and in situ conservation and education projects, to protect the species. All efforts to date have been a starting point for the conservation of this endemic species, but the final goals are to: (1) create a protected area for the White-footed tamarins in Colombia, (2) develop two breeding programmes for the species, one in Colombia and the other in Europe, (3) reduce capture of White-footed tamarins for the pet-trade market, through education initiatives, and (4) ease the pressure on the forest habitat that is still intact.

Estimating Population Density of Amazonian Titi Monkeys (Callicebus discolor) via Playback Point Counts

Abstract: We describe a new method for estimating population density of vocally responsive animals, which is based on playback calls coupled with auditory point transect sampling. The method yielded, for red titi monkeys (Callicebus discolor), better estimates than traditional line transect surveys. We propose it as an effective alternative for sampling certain cryptic, but vocally responsive animal species.

Macaque Societies. A Model for the Study of Social Organization

Abstract: Macaque Societies is a product of a conference, sponsored by the Wenner-Gren Foundation, held in March of 2001, in Mysore, India. In a superb introductory chapter, the editors define basic terms such as: networks, interactions, demographic structure and social organization. They present Tinbergen’s perspective distinguishing structure from the answers to the 4 why questions. The macaques are introduced and various lineages suggested. The chapter authors use the definitions consistently and, commendably, do not confuse outcome and motivation, natural selection and proximal cause. Some chapters clearly explain basic concepts, some are excellent reviews, some present correlational analyses, some elaborate previous positions, but few contain new data or approaches. All benefited from the conference; the views presented are consistent and modified by scholarship and discussion to acknowledge discrepant data. Flack and DeWaal refer to new data to support a complex theory of social relationships and political systems. The logic is flawless but their premises may be challenged. The 5 political systems are not all described and the measure of social power is ambiguous since the frequency of signals can vary independently of the number of individuals emitting the signals. They write that signals indicate “perceived agonistic asymmetry” (p. 163), that “translational errors” on the part of animals explains incidents where a “formal dominance signal” fails to be used as expected and that chimpanzees might “. . . vote for the top males.” (p. 180). Conversely, Hemelrijk uses a computer simulation based on a few simple rules to generate the same social relationship data without invoking cognition or any higher level organizational principles. The proximal mechanisms suggested are far more parsimonious; granted parsimony is

On a New Species of Titi Monkey, Genus Callicebus Thomas (Primates, Pitheciidae), from Western Bolivia with Preliminary Notes on Distribution and Abundance

Abstract: This paper describes a new species of titi monkey, Callicebus aureipalatii, recently discovered in the Madidi protected area of northwestern Bolivia. Descriptions are based on observations, photographs and video material, and the subsequent collection of two specimens. Preliminary surveys and notes on habitat associations indicate that C. aureipalatii is limited in distribution to the western side of the Rio Beni. It is found in the Andean foothills and immediately adjacent lowland forests. Line transect studies at four sites and subsequent extrapolations based on available suitable habitat suggest that population densities are sufficiently high to ensure the protection of this species within the confines of the Madidi protected area. This finding is discussed with reference to the general lack of knowledge regarding titi monkey distributions in Bolivia.

Abundance, habitat use and diet of Callicebus nigrifrons Spix (Primates, Pitheciidae) in Cantareira State Park, São Paulo, Brazil

Abstract: Between april 2005 and May 2006, according to the pressuposts of line transect methodology, census were carried to estimate abundance and population density of Callicebus nigrifrons Spix, 1823 (Pitheciidae) in Cantareira State Park, State of Sao Paulo, southeastern Brazil (23°23'42"S, 46°35'27"W). After 275.80 Km of census sampling effort, the titis were the second most abundant primate species, presenting an abundance index of 1.4 groups for each 10 km walked and a density estimate of 12.21 ind./km2 (ranging between 8.45 a 17.63 ind./km2). The collection of ancillary data during the census allowed the determination of diet and habitat use by the titis groups, and results show a relative adaptability to disturbed habitats.

Primate Group Size and Abundance in the Caatinga Dry Forest, Northeastern Brazil

Abstract: The Caatinga dry forest poses a series of ecological challenges for mammals in general and primates in particular. The erratic rainfall pattern impacts on plant diversity and phenological patterns; from year to year there is marked variability in fruit production and failure to fruit is common. The harshness apparently accounts for the impoverished mammalian fauna. However, data on primate abundance, distribution, and possible environmental effects on primate density are lacking in this type of dry forest. I censused the primate community in 3 habitats of the Serra da Capivara National Park, Piaui, NE Brazil, over a total distance of 318 km. Overall, the abundance of primates in the Caatinga dry forest is very low as a consequence of low abundance of food resources both in space and time. Alouatta caraya (predominantly folivorous) occurs at extremely low density, and during the dry season are apparently confined to canyon areas, where trees retain their leaves. Callithrix jacchus has morphological feeding specializations for gum-eating, and gum is an important resource during food bottleneck periods. Nonetheless, Callithrix jacchus occurs at comparatively low densities. Group sizes for howlers and marmosets in the Caatinga are significantly smaller than in other forest types. Contrarily, Cebus apella libidinosus had an average group size within the range reported for Amazonian and Atlantic forests. Researchers consider the generalized diet of capuchins as the explanation for their similar abundance in different habitats, indicating relative independence from ecological constraints. However, I suggest that capuchin foraging style and cognitive abilities are important factors accounting for their unreduced group size and density even under extreme conditions.