Estimating primate densities from transects in a West African rain forest: a comparison of techniques

G. H. Whitesides, J. F. Oates, S. M. Green, R. P. Kluberdanz

Research output: Contribution to journalArticlepeer-review

163 Scopus citations


Assessed the densities of social groups of 7 diurnal primate species (sooty mangabey Cercocebus atys, diana monkey Cercocebus diana, Campbell's monkey Cercopithecus campbelli, lesser spot-nose monkey Cercopithecus petaurista, red colobus Procolobus badius, olive colobus Procolobus verus, black-and-white colobus Colobus polykomos) resident on Tiwai Island, Sierra Leone. A modified standard species-specific strip-width estimation technique was applied to data from 28 single-observer transect samples, each 6 km in length. A 2nd method employed 17 sweep samples where 2 observers simultaneously walked parallel transects 100 m apart and 1 km in length. This method used both sightings and localization of vocalizations for density estimation. A 2nd method transformed sighting rates from the single-observer samples into density estimates by incorporating sighting rates and densities from sweep samples into calibration factors. Long-term data on home-range size and overlap were used to estimate density for 3 species for which there was sufficient data. A 5th method used the hazard-rate model of Hayes & Buckland (1983) which involved transforming estimates of distance to the first sighted individual into estimates of distance to the group centre. The rank orders by species of density estimates produced by all analytical techniques were identicial except for the sweep-quadrat method. There were no significant differences among density estimates produced by different analytical methods, except for the C. diana density produced by the sweep samples. Use of both relatively long single-transect samples and also more localized multi-observer sweep samples is recommended. These techniques allow use of a variety of analytical methods. -from Authors

Original languageEnglish (US)
Pages (from-to)345-367
Number of pages23
JournalJournal of Animal Ecology
Issue number2
StatePublished - Jan 1 1988

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


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