Cortisol response of wild ungulates to trauma situations: hunting is not necessarily the worst stressor

Animal welfare concerns are becoming a central issue in wildlife management and conservation. Thus, we investigated stress response of wild ungulates to potentially traumatic situations (shooting injuries, vehicle collisions, entanglement, injuries or diseases) and hunting methods (stalking, battues and hunts with dogs) by means of serum cortisol concentrations from blood collected from killed animals. Cortisol levels in roe deer ranged below and in wild boar above levels for moose, red deer and fallow deer (hence, pooled as a group “deer”). Apart from species, cortisol concentration in trauma situations was mainly explained by trauma type and presence of disturbance after the trauma event. Effect of trauma type differed significantly for “deer”, with animals caught in fences and suffering vehicle collisions experiencing higher cortisol levels than animals injured by shooting. Differences between hunting methods were observed in the cervids (“deer” and roe deer), with stalking leading to lower cortisol levels than hunts with dogs (both groups) and battues (roe deer). Events both before and after the shot, such as duration of pursuit prior to shooting, location of injury, trauma length and presence of disturbance after the shot were relevant for cortisol levels in hunted cervids. Our results indicate that search teams tracking and euthanising wounded animals should behave in a calm way to minimise disturbance. Still, it is important to acknowledge that many situations described in the literature, i.e. reindeer handling, roe deer captures and red deer yarding, seem even more stressful, beside vehicle collisions, than most hunting methods.