Development and Assessment of a Body Condition Score Scheme for European Bison (Bison bonasus)

Resettlement projects of the strongly threatened European bison (Bison bonasus) require a monitoring phase to assess both population status and habitat quality. Schemes of animal body condition scores (BCS) are robust tools to meet this requirement in practice. However, so far, no BCS scheme has been designed for European bison. Here, we suggest a body condition score scheme based on the extent of soft tissue around bony structures. The scoring system was developed with scores ranging from 1 (emaciated) to 5 (obese). Condition scores can be deduced after visually assessing the European bison both from the side and behind. Robustness of the scheme was evaluated: Unbiased people from different professional backgrounds were asked to assess the BCS of photographed semiwild European bison under field conditions and results were compared. Results demonstrate the suitability of the method. Nevertheless, variability of the results among assessors illustrates the necessity for training as well as for further research to validate the scheme as a true measure of physiological condition. We discuss the prospects and limits of a broad use of this scheme within the European bison community, and recommend the BCS scheme as a management tool.