How do seasonal changes in adult wolf defecation patterns affect scat detection probabilities?

Abstract. Wolves are currently recolonising their historic range in France. The collection of scats is a widely used a non-invasive survey method to monitor wolf population size. However, seasonal changes in wolf faecal deposition patterns might affect the results of surveys. We used a detection dog and camera trapping (CT) to compare wolf scat detectability during winter and the nursing season. We collected 113 scats deposited by adult wolves at 29 marking sites on forest roads in the Sainte-Baume Regional Park, Provence, France. After parturition, the mean number of adult wolf scats increased by 160% inside the nursing territory and decreased by 80% outside of it. Around the time the pups are born, changes in faecal deposition patterns of adults make it easier to find scats around the wolf den (87% probability per wolf marking site) and harder to find scats outside the nursing territory (11% probability). During winter, the chance to find scats is equal (38 to 40% probability per wolf marking site) inside vs. outside the nursing territory. The combined use of a detection dog and camera traps allowed us to gather data on wolf defecation patterns non-invasively. Detectability of adult wolf scats during the nursing season is highly variable compared to winter due to seasonal behavioural changes affecting scat location. We conclude that surveys to collect samples and estimate wolf population size should be conducted exclusively during winter to avoid sampling biases.