Behaviour of newly hatched and adult Japanese quail was analyzed using videorecordings from two experiments conducted aboard the MIR orbital station. Weightlessness caused problems in motor behaviour of unrestricted quail. Especially in newly hatched quail (their entire embryogenesis proceeded under microgravity conditions) bodily rotations and bouncing against the walls of the rearing device ''Nest'' did not allow them to feed. The problems with movement and spontaneous feeding were not so serious in adult, unrestricted birds. Although some signs of adaptation to microgravity could be seen, further data are necessary for estimating possibilities of behavioural adaptation to microgravity.