Behavioural and adrenocortical coping strategies and the effect on eosinophil leucocyte level and heterophil/lymphocyte-ratio in beech marten (Martes foina)

Adaptation to captivity was examined in 18 female beech marten (Martes foina), all captured and kept in the experimental cage systems for 9 months prior to the study. The behaviour of the animals was recorded over 24 h and feed intake measured in two periods over 5 days. Plasma cortisol concentration, number of eosinophil leucocytes and the heterophil/lymphocyte-ratio were measured by repeated blood sampling in the day and night hours. The purpose of the investigation was to evaluate the adaptation to captivity by establishing on the individual level the association between total activity, stereotypic activity and plasma cortisol. On the basis of the possible association, eosinophil leucocytes and heterophil/lymphocyte-ratio were indicators of welfare, demonstrating the applicability of the physiological variables. The results made it possible to conclude that the population can be divided into two types with regard to coping strategy. An active type characterized by a high activity level (A), in which the majority of activities is of stereotypic nature, and a passive type with a low activity level (B) not showing any stereotypic behaviour. Active beech marten are furthermore characterized by a considerably larger feed intake than passive beech marten. Active beech marten react to acute stress by increased stereotypic behaviour and a faster and larger cortisol response than passive beech marten which react by a generally reduced activity. Type A has a higher basic level of eosinophil leucocytes and a longer lasting reduction of the level as a response to repeated acute stress than B. At repeated acute stress, A reacts with a quicker and more constant increase in the heterophil/lymphocyte-ratio than B. At the same time a circadian variation in plasma cortisol concentration and number of eosinophil leucocytes was demonstrated, showing that the levels were higher in the morning than in the evening.