1. Camera traps deployed in grids or stratified random designs are a well-established survey tool for wildlife but there has been little evaluation of study design parameters.2. We used an empirical subsampling approach involving 2,225 camera deployments run at 41 study areas around the world to evaluate three aspects of camera trap study design (number of sites, duration and season of sampling) and their influence on the estimation of three ecological metrics (species richness, occupancy and detection rate) for mammals.3. We found that 25-35 camera sites were needed for precise estimates of species richness, depending on scale of the study. The precision of species-level estimates of occupancy (ψ) was highly sensitive to occupancy level, with <20 camera sites needed for precise estimates of common (ψ > 0.75) species, but more than 150 camera sites likely needed for rare (ψ < 0.25) species. Species detection rates were more difficult to estimate precisely at the grid level due to spatial heterogeneity, | 701Methods in Ecology and Evoluঞon KAYS et Al.

Large and medium-bodied rainforest canopy mammals are typically surveyed using line transects, but these are labour intensive and usually ignore nocturnal species. Camera traps have become the preferred tool for assessing terrestrial mammal communities, but have rarely been used for arboreal species. Here, we compare the efficiency of arboreal camera trapping with line transects for inventorying medium and large-sized arboreal mammals, and assess the viability of using camera traps in trees to model habitat occupancy. We installed 42 camera traps, spaced 2 km apart, in the canopy of the Maijuna-Kichwa Regional Conservation Area, Peru and walked 2014 km of diurnal line transects on 22 trails at the same site. We compared the efficiency of each method using species accumulation curves. We applied a multi-species occupancy model, while examining the effect of camera height on detection probabilities, including the distance from a village and from a river as covariates to examine variability in habitat occupancy. In 3147 camera days, 18 species of arboreal medium and large-sized mammals were detected by cameras, while 11 species were recorded on line transects. Ten of these species were detected by both methods. Diurnal species were detected more quickly and with less effort using arboreal camera trapping than using diurnal line transects at the same site, although some species were more easily detected during line transects. Habitat occupancy was positively correlated with distance from the village for two species, and negatively correlated with distance from the river for one. Detection probabilities increased modestly with camera height. Practical limitations of arboreal camera trapping include the requirement for specialized climbing techniques, as well as increased potential for false triggers, requiring extended processing time. Arboreal camera trapping is an efficient method for inventorying arboreal mammals and a viable option for studying their distribution relative to environmental or anthropogenic variables when abundance or density estimates are not required. 146

Primates living in large groups that divide to forage must have social systems compatible with this mode of living. Uakari monkeys (Cacajao spp.) live in large groups and exhibit a form of fission-fusion grouping, but their social organization is poorly understood. We present some of the first data on social behavior for this genus based on a study on Cacajao calvus ucayalii. They traveled in multimale multifemale groups of highly variable sizes, with bachelor units on the periphery. Adult males were affiliative, and adult females associated with more than one adult male. Adult females typically traveled with their dependent offspring and an older juvenile within the group. In parties of two or more males, individuals engaged in previously unreported display behaviors and acted together to aggressively chase other males. Breeding was seasonal, and mating occurred away from other group members. We speculate on the social organization of C. calvus ucayalii, in which dispersal may be bisexual and peripheral males are affiliative with one another. Affiliated males appear to cooperate in fighting and displaying to other males for access to females during the breeding season.

Wildlife subsistence hunting is a major source of protein for tropical rural populations and a prominent conservation issue. The intrinsic rate of natural increase. (r ) of populations is a key reproductive parameter in the most used assessments of hunting sustainability. However, researchers face severe difficulties in obtaining reproductive data in the wild, so these assessments often rely on classic reproductive rates calculated mostly from studies of captive animals conducted 30 years ago. The result is a flaw in almost 50% of studies, which hampers management decision making. We conducted a 15-year study in the Amazon in which we used reproductive data from the genitalia of 950 hunted female mammals. Genitalia were collected by local hunters. We examined tissue from these samples to estimate birthrates for wild populations of the 10 most hunted mammals. We compared our estimates with classic measures and considered the utility of the use of r in sustainability assessments. For woolly monkey (Lagothrix poeppigii) and tapir (Tapirus terrestris), wild birthrates were similar to those from captive populations, whereas birthrates for other ungulates and lowland-paca (Cuniculus paca) were significantly lower than previous estimates. Conversely, for capuchin monkeys (Sapajus macrocephalus), agoutis (Dasyprocta sp.), and coatis (Nasua nasua), our calculated reproductive rates greatly exceeded often-used values. Researchers could keep applying classic measures compatible with our estimates, but for other species previous estimates of r may not be appropriate. We suggest that data from local studies be used to set hunting quotas. Our maximum rates of population growth in the wild correlated with body weight, which suggests that our method is consistent and reliable. Integration of this method into community-based wildlife management and the training of local hunters to record pregnancies in hunted animals could efficiently generate useful information of life histories of wild species and thus improve management of natural resources.