Practitioners have expressed growing concern over accuracy, precision and efficiency of playback methods, which involve playing a recording of the target species’ song at potential nest sites and listening for a bird to respond. Even when nests are known to be occupied, response rates are typically low, gender specific and are known to vary among colonies. The method is therefore very labour intensive and, for colonies with large areas of nesting habitat, a sampling approach is necessary. This often leads to large confidence limits and low power to detect changes in population size.
Work is urgently needed to improve existing playback methods, and evaluate novel methods emerging from advances in technology such as infra-red imaging, which may offer more cost-efficient and precise approaches.