Do you see what I see? Variation in detection, identification and enumeration of mammals during transect surveys

Abstract

AbstractEffective monitoring, management and conservation of wildlife axiomatically depend on accurate data but causes of variation, including inter‐observer variation, are rarely explicitly quantified. Here, under controlled conditions, we demonstrate considerable variation in detection, identification and enumeration of (theoretically) readily identifiable African mammals at a reserve with a known species assemblage. Detection: 97.8% of sightings were missed by ≥1 observer; frequency of detection was affected by observer ID, detection distance, visibility and animal group size. Identification: just 3/14 species were identified consistently at all sightings. Enumeration: lack of consensus for 60.5% of sightings; consensus likelihood was affected by visibility and group size.