A literature review has been done to help identify which bird species should feature on General Licences 1, 2 and 3. Researchers studied scientific literature and assessed the evidence of impact for the listed species and species distribution during the past 25 years. Their research finds no evidence for rook impacting on the conservation of wild birds under General Licence 1. They also found little or no evidence for several of the species on General Licence 2 (issued to prevent serious damage to livestock etc.) or those listed on General Licence 3 (issued to preserve public health and safety, and preventing the spread of disease) although this might be due to gaps in evidence.
Publication 2019 - SNH Research Report 1136 - Literature review of the evidence base for inclusion of bird species listed on General Licences 1, 2 and 3 in Scotland