Threat-induced behavioural inhibition in Japanese quail genetically selected for contrasting adrenocortical response to mechanical restraint.

1. Behavioural and adrenocortical responses to brief mechanical restraint were examined in 28-d-old female Japanese quail of two lines which had been genetically selected over several generations for either reduced (LS, low stress) or exaggerated (HS, high stress) plasma corticosterone response to brief immobilisation in a metal box. 2. As expected, quail of the LS line showed lower adrenocortical responses to restraint than did their HS line counterparts. The LS quail also struggled much sooner and more often during the 5 min restraint period than did the HS ones. Collectively, these and previously reported line differences in behavioural, catecholamine and adrenocortical responsiveness are consistent with an interpretation based on the adoption of active and passive coping strategies respectively by LS and HS quail upon their exposure to alarming stimuli.