Pitfalls in using counts of roaring stags to index red deer (Cervus elaphus) population size

摘要: Counting roaring stags during the rut has been proposed as a means to assess deer population size and trends but few, if any, attempts have made evaluate reliability of this technique. By commonly used field protocol, we assessed what extent relative abundance estimates red (Cervus elaphus) based on roaring-stag counts in northern Apennines (Italy) were susceptible exogenous unpredictable sources variability. using up 26 simultaneous observers an area 5218 ha, estimated densities from 0.45 0.61 per 100 ha 3 consecutive years (1992–94), corresponding annual changes number counted ranging –21% +35.7%. However, only two three seasonal peaks activity apparent, timing survey was not always synchronous with peak. In addition, nocturnal variation activity, weather conditions survey, might influenced some extent, probably determining high Type I II error rates. We contend that additional error, associated unknown demographic ecological settings, may further increase unreliability technique when it is estimate absolute density populations. conclude by emphasising managers should use method for monitoring unless they can prove yield reliable results.