For conservation purposes, accurate methods are required to track cotton-top tamarins in their natural habitat. As existing census methods are not appropriate for surveying these monkeys, a lure-transect method combined with playback vocalization was used here to allow accurate counting of the animals.

Cotton-top tamains (Saguinus oedipus) are a critically endangered primate found only in Colombia. Efforts to conserve this species are centered on developing effective management plans that integrate biological information regarding population dynamics and factors that influence their survival. This study documented infants born to wild cotton-top tamarin females from 1994-2008 at two distinct field sites in northern Colombia. Our studies have shown that wild cotton-top tamarins typically give birth to one litter each year and infant survival to 6 months of age was greater in the wild than has been reported in captive colonies. However, similar to reports from captive colonies, litter size of wild cotton-top tamarins ranges from 1-3 infants, with twin litters most common. Here we report the first occurrence of triplet litters in nearly 20 years of observing wild cotton-top tamarin groups. Over the first 3 months of life, wild-born infants exhibited highest mortality during the first week of life, similar to reports from captive colonies. Infant survival in the wild also increases with successive litters as it does in captivity. However, inter-birth interval, group size, and the number of adult males in the group did not appear to influence infant survival in the wild. The value of such long-term data from field studies aids in the information that can be used to model future population trends and develop effective conservation plans for this critically endangered primate.

Studies of cooperative breeding species have suggested that helpers are needed for infant survival and that helpers gain skills to successfully raise their own offspring.Studies of callitrichids in managed care and early field studies suggested that group size correlated with infant survival and that helpers needed to learn parental skills to be successful breeders. We present infant survival data from a 20-year field study of cotton-top tamarins (Saguinus oedipus) in Colombia involving 126 litters born to 41 females. There was no difference in the survival of male and female offspring to 6 months of age. However, litter size impacted survival, with triplet litters having lower survival and male triplets having lower survival than females. Loss of infants was highest in the first week of life and, of the animals remaining in the group at 6 months of age, 90% of them survived to 1 year. The mean length of time in the natal group was 2.3 years but some young migrated to other groups after 4 months of age. Group size and number of male helpers (>1 year) was not related to infant survival. However, groups with only one male had fewer surviving infants.Primiparous females had lower infant survival, but previous infant care experience by mothers as helpers had no effect on survival. A major cause of infant loss was group disruption due to deaths/evictions/loss of the reproductively active animals, or immigration of pregnant females. Thus, factors that cause a change in the stability of the reproductively active animals can disrupt group cohesion. Capture of individuals for the illegal pet trade, as well as habitat fragmentation, may increase competition between groups for access to territories and breeding opportunities. This may have long-term impacts to infant survival in this critically endangered species.

Numerous animals have declining populations due to habitat loss, illegal wildlife trade, and climate change. The cotton-top tamarin (Saguinus oedipus) is a Critically Endangered primate species, endemic to northwest Colombia, threatened by deforestation and illegal trade. In order to assess the current state of this species, we analyzed changes in the population of cotton-top tamarins and its habitat from 2005 to 2012. We used a tailor-made “lure strip transect” method to survey 43 accessible forest parcels that represent 30% of the species’ range. Estimated population size in the surveyed region was approximately 2,050 in 2005 and 1,900 in 2012, with a coefficient of variation of approximately 10%. The estimated population change between surveys was -7% (a decline of approximately 1.3% per year) suggesting a relatively stable population. If densities of inaccessible forest parcels are similar to those of surveyed samples, the estimated population of cotton-top tamarins in the wild in 2012 was 6,946 individuals. We also recorded little change in the amount of suitable habitat for cotton-top tamarins between sample periods: in 2005, 18% of surveyed forest was preferred habitat for cotton-top tamarins, while in 2012, 17% percent was preferred. We attribute the relatively stable population of this Critically Endangered species to increased conservation efforts of Proyecto Tití, conservation NGOs, and the Colombian government. Due to continued threats to cotton-top tamarins and their habitat such as agriculture and urban expansion, ongoing conservation efforts are needed to ensure the long-term survival of cotton-top tamarins in Colombia.

Seasonal availability of resources can influence the timing and success of reproduction in primates. This study examines the annual pattern of conceptions, mid‐term (13 weeks) and full‐term (26 weeks) pregnancy losses, births, and infant survivorship of the Critically Endangered cotton‐top tamarin (Saguinus oedipus) at Proyecto Tití's long‐term field site in Santa Catalina, Colombia. Using 18 years of behavior, physical exam, and fecal steroid data (N = 51 females, 168 conceptions, 121 liters), fecal estrone conjugate (E1C) and pregnanediol‐3‐glucuronide (PdG) or progesterone (P4) profiles were examined to investigate the relationships between female reproductive patterns and reproductive success with feeding and climatic data. Cotton‐top tamarins demonstrated seasonal patterns of reproduction and pregnancy losses. We found positive correlations between peak conception and nectarivory, births and rainfall, and mid‐lactation and frugivory. High body mass mothers reproducing during the peak season were more likely to have infants survive. Overall, these results suggest that tamarins use a “relaxed income‐breeder” strategy. Cotton‐top tamarins appear to maximize reproductive output at the time of ovulation, and can reduce their investment in the current reproductive effort at many stages. Changes in food availability due to habitat loss and climate change will require the Critically Endangered cotton‐top tamarins to alter their reproductive strategies to survive.