A survey of apes was carried out between October 1996 and May 1997 in the Dzanga sector of the Dzanga-Ndoki National Park, Central African Republic (CAR), to estimate gorilla (Gorilla gorilla gorilla) and chimpanzee (Pan troglodytes) densities. The density estimates were based on nest counts. The strip transect census and the line transect survey method (Standing Crop Nest Count) were used to estimate the gorilla nest group density. The strip transect has been most commonly used to date. It assumes that all nest groups within the width of the strip are detected, but as this assumption is easily violated in the dense tropical rain forest, the line transect survey was also used. In this method, only the nest groups on the transect line itself should be detected. This method proved to be an adequate and easy technique for estimating animal densities in dense vegetation. The gorilla density of 1.6 individuals km À2 (line transect survey method) found for the Dzanga sector is one of the highest densities ever reported in the literature for the Western lowland gorilla. The density estimate for chimpanzees was 0.16 individuals km À2 (census method). The results of this study con¢rm the importance of the Dzanga-Ndoki National Park for primate conservation.

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Across the Congo Basin, human hunting pressure poses the biggest threat to small‐ and medium‐bodied forest ungulates (genus Philantomba and Cephalophus, commonly known as duikers). The exploitation of these species has cascading effects on larger ecosystem processes, as well as on human subsistence practices. This study compares encounter rates and estimated population densities of duiker species, specifically Philantomba monticola (blue duiker) in the Dzanga‐Sangha Protected Areas (APDS), Central African Republic (CAR). Data were collected using direct observations of individual animals during diurnal (135 km) and nocturnal (150 km) transects in the APDS, with abundance estimates produced using DISTANCE software. Transect data demonstrate that within hunted forests similar to APDS, nocturnal rather than diurnal transects yield more individual observations of ungulates. Despite hunting pressure in the region, estimates presented for APDS suggest some of the highest density estimates reported for blue duikers in western and central Africa (58.6 blue duikers per km2). This study directly contributes current regional data on the status of duiker populations at APDS and in the larger Sangha Trinational Landscape (TNS, UNESCO). More broadly, we highlight the potential importance of nocturnal transect data to the development of adaptive management regimes in hunted forests.