Investigating determinants of compliance with wildlife protection laws: bird persecution in Portugal

Conservation interventions are generally underpinned by formal rules. These rules often suffer from high rates of non-compliance which is difficult to investigate due to its clandestine nature. Here we apply socio-psychological approaches to investigate the prevalence and determinants of three illegal bird-threatening behaviours---shooting raptors, trapping passerines for consumption, and poison use---by surveying 146 respondents in Portugal. We apply the theory of planned behaviour to understand behavioural determinants, and an indirect questioning method, the unmatched count technique (UCT), to estimate behaviour prevalence. The UCT estimated a high prevalence of trapping for consumption (47 {\%} SE 15) and shooting raptors (14 {\%} SE 11); both estimates being higher than from direct questioning. Poisoning had a lower prevalence according to direct questioning (7 {\%}), while the UCT generated a negative estimate suggesting that poisoning is a particularly sensitive behaviour. Different demographic groups were associated with different behaviours and determinants; men with greater rule knowledge were more likely to trap birds, while locally born people were less likely to approve themselves, or to think others approved of, trapping. Those with more positive attitudes to poisoning were more likely to admit to it, and these positive attitudes were found more in older non-hunters. Rule knowledge was better in younger male hunters. These findings suggest that NGOs aiming to reduce poisoning could enlist the support of hunters, while locally born people may be more receptive than others to working with NGOs to reduce trapping. These groups may be powerful allies in reducing illegal behaviours in their communities