The activity pattern of the forebrain of male zebra finches was investigated by the [14C]2-deoxyglucose (2-DG) method in 4 different behavioral situations. Sitting alone in the cage (control); courtship by experienced birds; first courtship of inexperienced birds (100 days of age), and chasing the birds around the cage. The primary sensory areas (ectostriatum, field L) were active above background in each experiment. Vocal-motor control areas were at background activity (RA, HVc, MAN), or below background (area X), all unaffected by the type of experiment. In contrast, 4 different areas were active in Expts. 3 and 4, but not in 1 and 2: part of the neostriatum intermedium; part of the lateral neostriatum, both with adjacent parts of the hyperstriatum ventrale, hyperstriatum accessorium and hyperstriatum dorsale, a portion of the caudal neo/archistriatum. It is concluded that the enhanced activity of these areas is not due to distinct external stimulation or enhanced motor activity, but correlates with high arousal levels of the animals.