For migratory birds, sustainable harvest management based on quantitative modelling needs cross-border hunting bag statistics. At the European scale, proper modelling requires both reliable and mutually compatible hunting bag data between regions and countries. Owing to the absence of harmonisation among the different hunting bag collecting schemes in Europe and the lack of methodological metadata, adaptive management at the flyway scale is currently extremely challenging for a number of species. For improving the current state of affairs, we expose statistical concepts, terminology and issues inherent to hunting bag data collection schemes; identify the multiplicity of error sources for being able to judge the quality of hunting bag statistics; call for a harmonisation process; discuss the origin of the hurdles in the production of standardised hunting bag statistics at the European scale; and suggest some potential avenues for future actions for overcoming them.