2.3. Data collection
Data collection was based on semi-structured interviews giving the interviewee the opportunity to develop his answers but also to give his point of view (Relun et al., 2015). The questionnaire was implemented among hunters and pig farmers. The questionnaire consisted of 30 questions for hunters and 50 for pig farmers and the time required to answer the various questions of the two questionnaires was estimated at 20 and 30 minutes respectively. This questionnaire was previously tested with a hunter and a breeder to verify the understanding of the different questions and the response times. Before beginning the interview, the interviewer explained the aim of the study and emphasized that the information the hunters and the farmers provided would be processed anonymously.
The questionnaire for hunters included different questions related to the 2017-2018 hunting season except for the last question which referred to the observation of interactions within the last 10 years. The questionnaire was divided in two parts: the first was based on the description of the hunting area and on the management of hunting activities, while the second focused on the nature and frequency of the different interactions between wild boars and domestic pigs observed during last seasons.
For the questionnaire intended for farmers, all questions referred to the observations of interactions occurring between 2017 and 2018. The first part of the questionnaire was related to the farm characteristics; the second part addressed questions on management and farming practices. Finally, the third part focused on the nature and frequency of the different interactions between domestic pigs and wild boars observed by the farmer and the last part explored other human practices related to potential indirect interactions (slurry or slaughtering offal disposal).
A wild boar incursion, was defined as the fact of observing a wild boar in the farm or observing any evidence of potential visits (broken fence, tracks, birth of hybrids). An interaction was defined as the direct observation of wild boar or domestic pigs mating, fighting or foraging together within the farm. Reports of incursions and interactions were merged together into a single “contact” variable for the analysis. Finally, observations of wild boars by the farmers around their farms were also recorded during the survey.