Accuracy and precision of skink counts from artificial retreats
Index counts are commonly used to detect spatial and temporal changes in the size of wildlife populations. For indices to be valid there must be a constant (usually linear) relationship between the index and population size. In a study conducted in the Eglinton Valley (Fiordland, South Island, New Zealand), single-day index counts of common skinks (Oligosoma polychroma) from artificial retreats were compared with capture–mark–recapture (CMR) estimates of population size (Nˆ) obtained by pitfall trapping.